Face-Centered Cubic Vacuum from Discrete Entanglement Networks

Emergent Face-Centered Cubic Vacuum from
Discrete Entanglement Networks
Forced
K=12
Saturation and an Emergent Light Cone
Raghu Kulkarni
SSMTheory Group, IDrive Inc., Calabasas, CA 91302, USA
raghu@idrive.com
Abstract
We ask what large-scale geometry follows if the vacuum is a discrete entanglement
network instead of a continuum. Close packing, a causal signal cone, and approx-
imate isotropy all arise from the network's own growth and dynamics, rather than
being imposed. The treatment has two parts.
Part I: kinematic construction.
Two local operators build the network: a planar
stitch and a rare out-of-plane lift, suppressed by a factor
e
3
. Under this rule the
network passes through a frustrated tetrahedral foam (Regge decit
δ 7.36
) and
closes at the Kepler kissing bound [3]. We formulate the operators as a reversible
Markov process on bond complexes carrying no coordinates or metric, and prove
that it concentrates on maximally bonded complexes whenever the congurational
entropy of the decit sectors is bounded. Exhaustive enumeration through
N=8
conrms reversibility and stationarity to residuals below
7 × 10
18
, and shows that
the lift suppression shifts kinetics without moving the equilibrium. Because proxim-
ity bonding counts contacts, the physical energy lives on an embedded state space,
and we state which results transfer to it.
Maximizing contacts gives close packing at every size enumerated. Such a packing
carries the identity spatial metric as its local bond second moment, and an explicit
[[192, 130, 3]]
CSS code at
67.7%
rate on its edges [21].
Part II: dynamical foundations.
One bond Hamiltonian, coupled to a thermal bath,
supplies the dynamics beneath that growth. Its dissipative limit assembles the lattice
at the detailed-balance rate
q = 1/(1 + e)
. Its coherent limit propagates a ballistic
front at
c = 4
2 v
lat
. We prove that
K=12
is a
forced
terminus. The largest
cuboctahedral vacancy sits at
R
=
p
2
2 L
, so no thirteenth neighbor ts. The
lift rate factorizes into a free geometric acceptance and a xed thermal factor
e
3
.
The model must supply one further scale, a bond rigidity
κL
2
36 ε
, which a single-
scale vacuum cannot meet. Matching the signal cone to the elastic trace speed then
xes the stiness at
κ = 16
2
/
2
.
1
Part I
Kinematic Construction
1 Introduction
The constructive generation of three-dimensional macroscopic spaces from discrete, fun-
damental components is a central problem in statistical mechanics, network theory, and
discrete models of quantum gravity [1, 4].
The obstacle.
A persistent obstacle is geometric frustration. When discrete nodes
are assembled via purely randomized three-dimensional probabilistic rules, the resulting
structures typically resemble diusion-limited aggregation [2] or kinematically jammed,
fractal-like foams. These porous congurations fail to achieve the dense, uniform coor-
dination required to mimic a continuous, isotropic spatial bulk. For a discrete spatial
model to be physically viable, it must demonstrate a natural kinematic pathway to struc-
tural saturation. In three dimensions, optimal spatial saturation is formally dened by
the Kepler conjecture, which dictates a maximum coordination number of
K = 12
[3].
Achieving this state purely through local, bottom-up assembly rules without imposing a
global background coordinate system remains a signicant computational challenge.
The approach.
In this paper we explore a resolution to this geometric bottleneck by
altering the dimensional probabilities of the generative kinematics. Motivated by holo-
graphic models of boundary-volume correspondence [4, 5], we hypothesize that saturated
3D volumes can be deterministically generated if the underlying assembly process is over-
whelmingly two-dimensional.
The model.
We work with the Selection-Stitch Model (SSM), seeded by a Bell-pair
triangle, three unit-distance bonds joining three nodes, the minimal closed simplicial unit,
and extended by two topological operators: a 2D lateral expansion (the stitch) and a rare
out-of-plane 3D projection (the lift). The relative amplitude of these operators is taken
as
P
lift
= e
3
4.98%
, motivated by the codimension dierence between their solution
manifolds (Section 2.2) and consistent with the QEC survival ansatz of the
[[192, 130, 3]]
CSS code that the emergent lattice supports (Sections 2.3 and 5); Part II derives this value
as the thermal factor of the lift rate, the geometric prefactor remaining free (Section 17).
What follows.
Under these constraints the system traces a kinematic cascade
K = 1
K = 6 K = 4 K = 12
, escaping the geometrically frustrated
K = 4
tetrahedral
foam [9] and closing at the Kepler bound. Ref. [22] demonstrates that cascade by direct
simulation.
Part I asks the sharper question that a simulation cannot settle: what does this dynamics
select
, and can the answer be proved rather than sampled? We therefore give the operators
a stationary measure and study what it favors. Section 3 sets up that measure and the
conditions under which the chain converges to it; Section 3.6 veries those conditions
exactly on small state spaces; and Section 3.8 shows that the favored phase carries a at
isotropic spatial metric built from its own bond directions.
2
Relation to the companion papers.
The stitch and lift operators were introduced by
the author in Ref. [22], which reports a growth simulation of the resulting cascade and its
saturation statistics. This paper does not repeat that simulation. Part I instead formu-
lates the same operators as a reversible Markov process on pre-geometric bond complexes,
and establishes by exact enumeration the reversibility and concentration properties that
the growth picture assumes. The
[[192, 130, 3]]
CSS code of Section 5 is constructed in
Ref. [21]. Everything else is new: the selection-by-persistence motivation for the bond
and the operators, the error-correction reading of the lift amplitude, the nite-state veri-
cation, and the whole of Part II.
Interactive 3D Visualization.
A 31-frame animated WebGL application
showing step-by-step lattice growth, from the seed triangle through 2D sheet
expansion to
e
3
out-of-plane lift events, is available at:
https://raghu91302.github.io/ssmtheory/qec_spacetime_3d.html
Nodes are color-coded by coordination (
K = 12
green,
K = 10
11
orange,
K < 10
red). Controls: play/pause, frame stepping, drag to orbit, scroll to
zoom.
2 Methodology
This section denes the operators, the amplitude that weights them, and the parameters
they act on. Section 3 then embeds them in a dynamics and asks what that dynamics
selects.
Growth is unbounded. The complex extends freely from the seed triangle, with no periodic
wrapping, xed walls, or imposed cell. Its boundary is a free surface set by the kinematics
instead of by a container, so under-coordinated nodes sit at that surface. Ref. [22] exploits
this in its surface-to-volume analysis of the growth simulation.
2.1 Generative operators and proximity bonding
Motivation, not derivation.
The bond and the two operators below are posited, and
the construction takes them as given. The picture that motivates them is set out below,
as motivation rather than derivation.
Suppose the initial condition carries no structure: no geometry, no ordering, only a space
of possibilities. There what happens next has no content, because next is not yet
dened, and the only question with content is which congurations
persist
. Correlations
between pre-geometric degrees of freedom form and, in the overwhelming majority of
cases, do not last. Once a geometry exists, transient correlations of this kind are the
model's counterpart of vacuum uctuations, whose physical eects are well established.
Why entanglement.
We make no claim about what else was possible. Whatever failed
to produce persistent structure left nothing behind to be inventoried. The answerable
question is structural instead of historical. Classical correlation places no bound on how
many partners a node may hold at full strength, so a classically correlated network has
3
no kissing-number analog, no saturation, and no close packing. Entanglement is monoga-
mous, and that is what makes coordination a bounded quantity at all. Section 16 weighs
the same constraint against codeability.
Why the triangle.
An isolated correlation has no closure. An open link is not an
observable, and only closed loops are [6]. The minimal closed object on a bond complex is
the triangle, and closure is what gives it a survival advantage, since a closed loop supports
a consistency check that an open link does not. This is the redundancy argument of
Sections 2.3 and 2.4 in its most elementary form, and carries the same heuristic status.
Status of this motivation.
Nothing in the paper's results depends on it, and four caveats
apply. The argument is circular as given, since extend presupposes the sequencing it is
meant to explain. Part II does not implement the emergent-ordering reading. Its dynamics
evolves in an external Schdinger parameter
τ
0
=
(Section 10), so ordering there is
an input, exactly as position is (Section 14). The vacuum-uctuation comparison runs
one way only. Persisting correlations are what such uctuations
become
once a geometry
exists, not the substrate from which geometry is built. The monogamy appeal likewise
concerns which correlations
could
support a bounded coordination, not a reconstruction
of what occurred.
The Bell-pair primitive and the triangular seed.
We treat the unit Bell-pair
bond(two nodes joined at distance
L
, the discrete structural analog of a maximally en-
tangled pair)as the primitive entanglement element of the network. The construction
begins from three connected Bell-pair bonds forming an equilateral triangle of side
L
; this
Bell-pair triangle is the minimal closed simplicial unit that the kinematic operators below
can act on, and the FCC lattice grows from it. We use Bell pair here in a structural
rather than dynamical sense: Part I is a combinatorial model and does not implement
gauge elds, a Wilson action, or a Hamiltonian. The connection to lattice gauge theory
is purely geometric, the triangle is the minimal closed loop on a simplicial complex, and
we adopt this terminology to motivate the structural operators.
The vacuum lattice grows from this seed via two kinematic operators. Growth is ltered
by the same criterion as the seed. Each addition either creates new closure or does not.
Stitch (2D expansion):
In gauge theory, a single open link is not a physical observable;
only closed loops are gauge-invariant [6]. The minimal physical entanglement structure on
a simplicial complex is the triangle. The stitch operator generates these minimal closed
gauge-invariant loops by placing a new node at the equilateral apex of an existing edge,
growing planar
K = 6
hexagonal sheets. Geometrically, the stitch realizes the intersection
of two unit spheres centered on the existing edge endpoints, a 1-parameter (1D) solution
manifold in 3D.
Lift (3D volume generation):
Projects a new node orthogonally from an existing
triangular face at the strict tetrahedral height
h =
p
2/3 L
. This height is not a free
parameter; it is the unique altitude of a regular tetrahedron with edge length
L
, the only
distance at which all four inter-nodal separations equal
L
. Geometrically, the lift realizes
the intersection of three unit spheres centered on the triangle vertices, a 0-parameter (0D)
solution manifold consisting of exactly two points (one selected by orientation).
Minimal operator basis.
Under the stated assumptions, insertion of a single node at
a generic intersection of unit spheres, at xed unit bond length, stitch and lift form the
4
minimal local operator basis that strictly increases connectivity. Cooperative multi-node
insertions, bond rearrangements and swaps, non-generic four-anchor sites, and collective
registration moves lie outside this basis; no claim of exhaustiveness is made for them. The
stitch (2-sphere intersection) yields a 1D family; the lift (3-sphere intersection) yields a
0D pair; a four-sphere intersection in 3D is generically empty, so no third operator with
strictly greater connectivity can be dened. Together, stitch and lift form a complete
kinematic basis for
generic single-node insertion
in three-dimensional Euclidean space at
xed bond length, growth through two- or three-anchor sphere intersections; the multi-
node and rearrangement moves excluded above lie outside this basis.
Proximity Bonding:
As the network expands, any two nodes within a threshold radius
(
1.05 L
) automatically bind. This mechanism allows independent, adjacent 2D layers
to geometrically interlock, producing the
6(
in-plane
) + 3(
above
) + 3(
below
) = K = 12
cuboctahedral coordination of the FCC lattice .
The
K = 4 K = 12
cascade and its closure.
Acting on the Bell-pair triangle,
the two operators drive a kinematic cascade through the coordination phases
K = 1
(the
elementary Bell-pair entanglement bond, the per-node degree of an isolated pair)
K = 6
(stitched hexagonal sheet)
K = 4
(tetrahedral foam, the conguration produced by
lifts before proximity bonding closes the layers)
K = 12
(interlocked ABC-stacked
FCC). The
K = 4
tetrahedral foam is geometrically frustrated: regular tetrahedra cannot
tile three-dimensional Euclidean space because the dihedral angle of a regular tetrahedron
is
arccos(1/3) 70.528
, and packing ve tetrahedra around a shared edge consumes only
5 × 70.528
= 352.64
, leaving an irreducible Regge decit [9]
δ = 2π 5 arccos(1/3) 0.128
rad
7.36
.
(1)
This residual wedge is the geometric source of the
K = 4
instability and the driver that
pushes the system to
K = 12
. The cascade closes at
K = 12
because it saturates the
Kepler kissing-number bound [3]: no further operator at unit distance can act on an
already 12-coordinated node. The FCC unit cell [11, 12] hosts this saturated state via 8
tetrahedral and 4 octahedral interstitial voids per cell, with the 12 nearest neighbors of
each interior node arranged on a cuboctahedral shell .
Tolerance window from the Regge decit.
The exclusion radius
R
ex
= 0.95 L
and
proximity bond radius
R
b
= 1.05 L
are not independent free parameters: they form a
symmetric
±5%
tolerance window around the unit bond length, set directly by the Regge
decit. The wedge angle
δ 0.128
rad projects to a fractional bond-length jitter of
|sin(δ/2)| 0.064
at each node; the adopted symmetric window of half-width
5%
is of
this natural size (slightly tighter than the full jitter), and the wide plateau of Ref. [22]
shows that nothing depends on the precise width. The robustness of
K = 12
saturation
across the entire band
R
ex
[0.58, 0.99] L
(Ref. [22]) further conrms that the specic
value
R
ex
= 0.95 L
is not a tuned parameter.
2.2 Codimension suppression and the
e
3
lift probability
The stitch and lift operators dier in the dimension of their geometric solution manifolds.
The stitch is a 1-parameter family in 3D (intersection of two unit spheres), a continuous
classical path of least resistance. The lift is a 0-parameter family (intersection of three
5
unit spheres), requiring the simultaneous satisfaction of
S = 3
distinct unit-distance con-
straints. The relative amplitude
P
lift
/P
stitch
is exponentially suppressed in the codimension
dierence:
P
lift
= e
S
= e
3
0.04978,
(2)
where
S = 3
counts the independent codimensional constraints lifting the operator from
a continuous (1D) family to an isolated (0D) pair. The terminus itself does not select
this value:
K=12
is forced for any lift rate by the kissing bound (Part II, Section 17).
What the lift rate controls is the growth
morphology
: smaller
P
lift
produces at, poorly
interlocked sheet structures, while larger
P
lift
produces foams with poor crystalline order
(Table 2 of Ref. [22]). We treat equation (2) as a structural/kinematic motivation instead
of a derivation from a Euclidean tunneling action; the operating value
P
lift
= 0.05
is
taken from this codimension argument and tested against the volumetric-yield analysis of
Ref. [22].
2.3 Quantum error-correction interpretation of
e
3
The code the lattice supports.
The codimension-suppressed amplitude (2) receives a
second, independent motivation from the quantum error-correcting code that the emer-
gent lattice supports. The FCC lattice at the smallest system supporting this code (a
4×4×4
unit-cell arrangement, 192 edges) carries a
[[192, 130, 3]]
CSS quantum error-
correcting code [13, 21], with 192 physical qubits (edges), 130 logical qubits, encoding
rate
k/n = 67.7%
, and code distance
d = 3
. Its stabilizers are the weight-12 octahedral
X
-checks and vertex
Z
-checks dened in Section 5. The minimal closed gauge-invariant
loops on the simplicial complex, the triangular faces of the local coordination cluster [6],
underlie the compound error-detection argument that follows.
The survival ansatz.
A
node participating in
t
triangular stabilizer checks is protected by
t
independent error-
detection circuits. Below the correction threshold, the error suppression scales exponen-
tially with the decit. This motivates the survival ansatz below. It is a heuristic, not
a consequence of code distance. The distance
d = 3
guarantees correction of arbitrary
weight-one errors, and we claim no decoding model, noise channel, syndrome dynamics,
or threshold calculation behind Eq. (3):
P (
survive
|t) =
(
1
if
t d + 1
e
(d+1t)
if
t < d + 1
(3)
The exponential form is qualitatively consistent with threshold behavior in topological
codes [14], where logical errors below threshold are suppressed exponentially in the syn-
drome decit by direct analogy with thermal activation across a free-energy barrier in the
underlying random-bond Ising mapping of the toric code. The unit-coupling exponential
e
(d+1t)
is the minimal one-parameter form meeting three requirements. It saturates to
unity at the protection threshold
t = d + 1
. It decays monotonically with the decit
d + 1 t
. And it recovers the textbook below-threshold scaling
P e
in the large-
decit limit. It also places the structural prediction
P
lift
= e
d
, for the worst-case
t = 1
peninsula, at a value directly testable against simulation. The unit coupling is an ansatz
whose consequences we test computationally; the compound-QEC argument of Section 2.4
below is structurally robust to the specic functional form, depending only on the mono-
tonic increase of eective protection with neighborhood depth. A node produced by a
6
tetrahedral lift participates in exactly
t = 1
triangle. At code distance
d = 3
:
P
lift
= e
(d+11)
= e
d
= e
3
(4)
The same value as the codimension argument (2). The two routes are consistent rather
than independent. Both exponents count the same three simultaneous unit-distance con-
straints (the three anchoring bonds of the tetrahedral lift), read kinematically in one case
and as missing stabilizer protection in the other.
2.4 Compound QEC: why at growth dominates
The QEC framework explains why 2D growth dominates without being externally pre-
scribed. Throughout this argument the triangular plaquettes serve as
heuristic
local
checks: they are the closed gauge-invariant loops of the lattice, not stabilizer generators
of the
[[192, 130, 3]]
code itself, whose checks are the weight-12 vertex and octahedral op-
erators (Section 5). What follows is a motivation for the lift suppression, not a property
of the stated code.
The in-plane node.
A node in the interior of a hexagonal sheet has
K = 6
neighbors
and participates in 6 triangles. Each triangle shares 2 edges with neighboring triangles.
An error at the central node triggers a syndrome at all 6 surrounding stabilizer checks.
The error is also independently detectable through the triangles of the node's second-
nearest neighbors. Each of the 6 neighbors participates in 5 additional triangles beyond
the one shared with the central node, giving an additional set of compound detection
paths within 2 hops. The eective protection is well above the
d + 1 = 4
threshold, and
sheet-interior nodes survive at eectively 100%.
The out-of-plane node.
A lift node sits at the tip of a topological peninsula: 1 triangle,
3 bonds to the parent face, zero neighboring triangles for redundant detection. An error
at this node can be detected only through its single parent triangle. There is no second
independent check. The eective triangle count is
t
eff
1
.
The asymmetry.
The ratio of eective protection is much larger than the raw triangle-
count ratio of
6:1
, because compound detection paths grow with distance from the bound-
ary. A node
n
hops into the sheet interior accumulates compound detection paths from all
triangles within
n
-hop neighborhoods, while the out-of-plane peninsula remains capped
at 1. This makes any threshold-based selection rule, not just the specic formula (3),
preferentially destroy out-of-plane protrusions while preserving the sheet. The compound
QEC argument is structurally stable. It does not depend on the exact functional form of
the survival probability.
2.5 Informational driver of dimensional projection
The construction admits an information-theoretic reading of dimensional emergence. Ev-
ery bond represents a unit of entanglement. A 2D triangular lattice caps at
K = 6
,
yielding
3N
total bonds. A 3D FCC lattice reaches
K = 12
, yielding
6N
bonds. The
2D sheet possesses the potential for 12 connections per node but lacks the geometric
room. By projecting into a third dimension via the
e
3
codimension-suppression limit,
the system doubles its entanglement capacity.
7
The causal chain.
It runs as follows. Minimal gauge-invariant loops, the triangles [6],
assemble into
K = 6
sheets. Those sheets have unused bonding capacity. The codimension
dierence between stitch (1D solution manifold) and lift (0D solution manifold) suppresses
out-of-plane growth at
P = e
3
. Regge frustration of the intermediate
K = 4
tetrahedral
foam [9] then drives the cascade upward. Stacking to
K = 12
saturates the Kepler
bound [3]. Finally, the
[[192, 130, 3]]
CSS code supplies the error-correction framework,
and its distance
d = 3
is consistent with the same suppression amplitude under the
survival ansatz of Section 2.3.
2.6 Summary of kinematic parameters
Where each value comes from.
Every parameter of the construction comes from
foundational geometry. The lateral and lift heights are unique altitudes of regular triangles
and tetrahedra. The lift probability is motivated by codimension suppression and by the
QEC distance, and Part II obtains it as a thermal factor with a free geometric prefactor.
The proximity-bond and exclusion radii together form the symmetric
±5%
Regge-decit
tolerance window of Section 2.1. Table 1 provides the complete kinematic parameter
space. Ref. [22] conrms by sensitivity sweep that these operating values are not ne-
tuned.
Table 1: Kinematic parameters. All values are geometrically or thermodynamically de-
termined.
Parameter Value Derivation
Unitary metric (
L
) 1.0 Invariant relational distance
Lateral height
3
2
L 0.866 L
Equilateral triangle altitude
Lift height
q
2
3
L 0.816 L
Regular tetrahedron altitude
Lift probability
e
3
4.98%
Codimension suppression /
QEC (Sections 2.22.3)
Proximity bond (
R
b
)
1.05 L
Regge decit (
δ 7.36
,
Eq. (1))
Hard shell (
R
ex
)
0.95 L
Regge decit (Section 2.1);
plateau veried in Ref. [22]
Observed kinetic cuto
1
3
L 0.577 L
Circumradius of unit tri-
angle; operator-kinetic wall
(Ref. [22])
3 The assembly as a reversible Markov process
The operators of Section 2.1 dene which moves are possible. To ask which structures the
assembly
selects
, they must be embedded in a dynamics with a stationary measure. This
section does that, and the statements below are proved for the stated model or veried
by exhaustive enumeration instead of sampled.
8
3.1 Pre-geometric state space
A microscopic conguration is a nite object
C = (V, E, σ)
, where
V
is a set of nodes,
E
a
set of undirected bonds, and
σ
stores only the local combinatorial data needed to identify
admissible stitch and lift moves. No background coordinates, metric tensor, or curvature
eld appears in the fundamental state. Geometric realizations at unit bond length are
reconstructed
after
a move has been specied combinatorially.
Fix as seed
C
0
an oriented triangle. The smallest conguration on which both moves are
dened, and the minimal closed object of Section 2.1. The seed is not spacetime but a
nite relational boundary condition preventing the empty-state obstruction. For a node
cuto
N
, let
N
(C
0
)
be the set of congurations reachable from
C
0
by admissible stitch,
lift, and reverse moves without exceeding
N
nodes. The cuto makes the state space
nite, so the thermodynamic question becomes a sequence of nite problems followed by
N
.
3.2 Detailed balance and the stationary measure
Let
B(C) = |E(C)|
and assign the microscopic energy
E
0
(C) = εB(C)
. This count is the
construction
bond count
B
hist
, and the model it denes is written
M
hist
below; the physical
assembly uses a dierent count on a larger state space, and Section 3.9 denes both and
states what transfers between them. Kinetic suppression of the lift is placed in the
proposal
kernel rather than in the energy, which allows an informationally suppressed lift to remain
energetically downhill. For congurations connected by one elementary move let
Q(C, C
)
be the proposal probability, assumed only to satisfy
Q(C, C
) > 0 Q(C
, C) > 0
, and
take the MetropolisHastings acceptance rule [7, 8]
A(C, C
) = min
1, e
β(E
0
(C
)E
0
(C))
Q(C
, C)
Q(C, C
)
.
(5)
Proposition 1
(Detailed balance)
.
The kernel
P = QA
satises detailed balance with
respect to
π
N
(C) = Z
1
N
exp
βεB(C)
, Z
N
=
X
C
N
e
βεB(C)
.
(6)
For adjacent congurations this is the standard MetropolisHastings identity; for non-
adjacent pairs both sides vanish. The local logistic form
q/(1 q) = e
βε
of Section 14 is
the special case of symmetric proposals where a reverse move removes one bond; the full
kernel is needed when the numbers of eligible birth and deletion proposals dier.
Detailed balance identies a stationary measure but does not guarantee convergence to
it. Convergence needs the state space to be connected under the moves. If every non-seed
conguration contains at least one exposed non-seed node whose deletion is an admissible
reverse move, a precise form of the reversibility of construction histories, then repeated
deletion reaches
C
0
in nitely many steps, any two states communicate through the seed,
and a positive hold probability gives aperiodicity. The chain is then irreducible and
aperiodic, and
π
N
is its unique limit from every initial state. This condition is checkable
algorithmically, and we verify it below.
9
3.3 Entropy production and what selects the phase
For a transition
C C
the system and medium entropy changes satisfy
s
sys
+s
med
= 0
on an equilibrium trajectory pair, and during relaxation from a non-equilibrium distribu-
tion
ρ
t
the relative entropy
D(ρ
t
π
N
)
is non-increasing. Local bond order can therefore
increase while entropy is exported to the bath.
It is worth separating three roles that are often collapsed into entropy. Detailed balance
together with the bond energy determines the stationary measure
π
N
. Entropy production
drives relaxation toward it. And a free-energy competition between the bond energy and
the congurational entropy of the decit sectors determines which macrostate dominates
π
N
. In that competition the congurational entropy opposes concentration and the bond
energy drives it. Entropy production makes the relaxation irreversible and the equilibrium
phase attainable; it does not by itself supply the degrees of freedom, the scale
ε
, or the
direction of the selection.
3.4 Concentration on maximal bonding
Let
B
max
(N) = max
C
N
B(C)
and grade the state space by bond decit,
N,m
= {C :
B(C) = B
max
(N) m}
. Suppose the decit-sector counts obey
|
N,m
| a
N
|
N,0
|e
s
m
(7)
for constants
s
<
and
a
N
1
with
log a
N
= o(N)
. Then for
βε > s
,
π
N
B
max
(N) B(C) M
a
N
e
(βεs
)M
1 e
(βεs
)
,
(8)
which follows by summing the geometric series
π
N
(Ω
N,m
)
N
(Ω
N,0
) a
N
e
(βεs
)m
over
m M
. The tail is exponentially suppressed in the decit threshold at each nite
N
; a
thermodynamic statement additionally requires control of
a
N
and of how
M
scales with
N
.
The structure of the result is what matters here. Bond energy alone is not sucient,
because congurational entropy must also be controlled. The argument is generic, needing
only a graded state space and a bound of the form (7). But the space
N
and the bound
itself are those of the history-resolved model, and Section 3.9 states what does and does
not carry over to the embedded one. For nite systems the bound is measurable by
exhaustive enumeration, which is what we do next.
3.5 Exact bond bookkeeping
A history with
n
nodes built from the triangular seed by
s
stitches and
lifts satises
n = 3 + s + ℓ, B = 3 + 2s + 3 = 3n 6 s,
(9)
since the seed carries three bonds and each stitch adds two bonds and each lift three, while
either adds one node. Hence
B
max
(N) = 3N 6
, attained exactly by all-lift histories at
the node cuto, and the decit is
m = 3(N n) + s
. Restricted to the cuto layer the
decit is simply the stitch count: the low-temperature measure suppresses histories by
how many planar stitch events they contain relative to the all-lift sector.
10
3.6 Exact nite-state verication
We implemented the above for a history-resolved simplicial realization of the rules. The
seed is one oriented triangle, a stitch adds a vertex to a boundary edge forming two bonds
and one triangle, a lift adds a vertex to a boundary triangle forming three bonds and one
tetrahedron, and reverse moves remove the most recently exposed non-seed vertex. States
are deduplicated up to colored incidence-graph isomorphism with the seed preserved.
For
N = 4, . . . , 8
the complete reachable state spaces contain
3
,
9
,
30
,
124
and
588
congurations. In every case the transition graph is connected, every non-seed state has
an admissible reverse move, and detailed balance and stationarity hold to residuals below
7 × 10
18
. The stationary weight of the maximally bonded sector rises monotonically
toward unity as
βε
grows. The enumeration closes three gaps at nite size: proposal
asymmetry is handled exactly, irreducibility is checked on the actual reachable graph
instead of assumed, and the decit-sector entropy is measured rather than posited.
Limits of the entropy evidence.
The empirical slopes
ˆs
N
=
max
m>0
m
1
log(|
N,m
|/|
N,0
|)
come out as
0.000
,
0.000
,
0.405
,
0.172
,
0.186
for
N = 4, . . . , 8
. They vanish identically at
N = 4, 5
, so only three of the ve sizes are
informative; the sequence is not monotone, its largest value falling at
N = 6
; and the
prefactor
a
N
of Eq. (7) remains uncontrolled. This is direct model-specic evidence for
the bound at the sizes enumerated, not a proof of its thermodynamic-limit form, and no
trend in
N
should be read from these points.
Kinetic suppression does not move the equilibrium.
Give forward lift proposals a
relative weight
ρ > 0
while stitch and reverse proposals keep unit weight, then normalize
each proposal row. Because the acceptance factor (5) contains the reverse-to-forward pro-
posal ratio, Proposition 1 holds for every
ρ > 0
and the stationary measure is unchanged.
Only relaxation times and path statistics move. We veried this exhaustively at
ρ = 1
,
0.1
and
e
3
on every enumerated state space; at
βε = 1.5
the maximal-sector probabilities
agree to machine precision across all three kernels, with residuals below
6 × 10
17
. This
is the exact form of a distinction the rest of the paper relies on: the lift suppression is
kinetics, and the bond energy is what xes equilibrium (Section 17).
3.7 Which bond count is being maximized
The concentration result concerns whatever bond count enters the energy, and two dis-
tinct counts appear in this paper. The
construction
count
B
hist
is the number of bonds
introduced by the moves of a history. The
contact
count
B
cont
is the number of unit-
distance pairs in the embedded conguration, whether or not a move joined them. Close
packing is dened by the second. These are dierent functionals, and the relation between
their maximizers is computable instead of a matter of interpretation.
Exhaustive enumeration of embedded stitchlift congurations gives the answer. For
n 9
the two maxima coincide at
3n 6
and every construction maximizer is also a
contact maximizer. From
n = 10
they separate, and the maximizer sets become disjoint:
the contact maxima are
3n 5
,
3n 4
,
3n 3
at
n = 10, 11, 12
, reproducing the known
maximal contact numbers of hard-sphere clusters with short-range attraction [10], while
the degeneracy of the contact maximum collapses from 31 at
n = 9
to a unique maximizer
11
from
n = 11
onward.
The separation comes with a change of cell type. Every contact maximizer from
n = 10
onward contains octahedral cells, while no construction maximizer contains one at any
n
: by Eq. (9) the maximal-bond sector consists of all-lift histories, and a lift produces
only tetrahedra. Such all-tetrahedral complexes are geometrically strained, since a pure
tetrahedral fan around an edge cannot close and leaves the residual decit of Eq. (1). The
octahedral cell is precisely what the at close packing requires (Section 16) and what the
construction-bond sector cannot supply.
The stitchlift moves do reach the known optima, so the operator basis of Section 2.1 is
not too impoverished to construct the contact-maximizing congurations. The separation
reects the two counting conventions, not a limitation of the dynamics. The history-
resolved verication therefore tests the physical object at the sizes where it is performed,
and ceases to beyond them, in a way whose onset and mechanism are now known rather
than assumed. Section 3.9 sets out which of the two counts the energy carries and what
follows.
Contact maximization does not select FCC.
The small-
n
maximal-contact clusters
are reported as subsets of close packing, and at a dozen spheres a cluster is far too small to
distinguish FCC from HCP: both are Barlow packings and small fragments are common
to the two. Contact maximization therefore delivers close packing but does not by itself
select FCC. That selection is a separate question, answered by the stacking argument of
Section 16 instead of by any bond count.
3.8 The metric of the close-packed phase
The metric is not fundamental in the microscopic state; it is reconstructed from the bond
geometry once an embedding compatible with unit bonds is given. The lemma below is
a property of the close-packed conguration; Section 3.9 sets out the evidence that the
assembly reaches it. For a node
x
with bond directions
ˆn
j
(x)
, dene the local second-
moment tensor and its normalization
S
µν
(x) =
z(x)
X
j=1
ˆn
jµ
ˆn
jν
, g
eff
µν
(x) =
3
z(x)
S
µν
(x),
(10)
so that
g
eff
=
for an isotropic set of
z
unit directions. For the twelve nearest-neighbor
directions of the close-packed lattice, obtained as permutations of
(±1, ±1, 0)/
2
, the
o-diagonal contributions cancel by sign symmetry and each coordinate is non-zero in
eight directions with squared component
1/2
, giving
S
µν
= 4 δ
µν
, g
eff
µν
= δ
µν
.
(11)
A close packing therefore realizes the identity spatial metric through a local bond moment
rather than by stipulation. This is exact geometry, holding for any conguration whose
coordination shell is the cuboctahedron. Section 4 develops what the same bond set does
and does not establish about Lorentz invariance.
12
3.9 Two models, and what transfers between them
The construction and contact counts are not two labels for one model. They live on
dierent state spaces, so we dene both.
The history-resolved model.
M
hist
is the model of Sections 3.13.6: states are abstract
complexes
C = (V, E, σ)
with no coordinates, and the energy is
E
hist
(C) = ε B
hist
(C), B
hist
= |E(C)|.
(12)
This is what the enumeration veries. Its state space is nite and coordinate-free, which is
what makes exhaustive enumeration and entry-by-entry detailed-balance checking possible
at all.
The embedded model.
The physical assembly is not coordinate-free: proximity bond-
ing (Section 2.1) binds
any
two nodes within
R
b
= 1.05 L
, whether or not a move joined
them. That is a statement about positions, so the physical state is the pair
X = (C, x)
of
a complex and an embedding, and the physical energy is
E
phys
(X) = ε B
cont
(x), B
cont
= #{{i, j} : |x
i
x
j
| = L}.
(13)
Call this model
M
emb
. It is the model whose maximizers Section 3.7 enumerates.
What transfers, and what does not.
Detailed balance is algebraic: given a state
space, a proposal kernel obeying
Q(X, X
) > 0 Q(X
, X) > 0
, and any energy,
the MetropolisHastings rule (5) is reversible with respect to
π e
βE
. Proposition 1
therefore holds for
M
emb
as it does for
M
hist
.
Nothing else transfers automatically. Ergodicity was established through the removable-
exposed-node condition on
N
, and deleting a node from an embedded state also removes
proximity contacts, so irreducibility of the embedded transition graph has to be checked
instead of inherited. The decit-sector counts and the empirical slopes
ˆs
N
were measured
on
N
, and the embedded state space is a dierent set with a dierent grading. Con-
structing
M
emb
properly requires a rule for identifying geometrically congruent histories,
contact updates after each move, and reverse moves that remove contacts consistently.
We do not carry that out.
Table 2: What is established for each model. Detailed balance is algebraic and holds for
both; the remaining properties were veried on the history-resolved state space and are
not inherited by the embedded one.
M
hist
M
emb
Detailed balance, Prop. 1 exact exact
Irreducibility and aperiodicity veried,
N 8
open
Decit-entropy bound, Eq. (7) measured,
N 8
not measured
Concentration, Eq. (8) conditional,
N 8
open
Maximizers identied all-lift,
3n 6
close packing,
n 12
Where the two agree.
Section 3.7 xes the overlap:
B
hist
and
B
cont
share their maxi-
mizers through
n = 9
and separate at
n = 10
. The enumeration of
M
hist
runs to
N = 8
,
inside that range, so within the sizes actually veried the two models select the same
13
congurations. The verication is not testing the wrong object; it is testing the right one
over a range whose upper end is known.
Where the physical model leads.
Under
E
phys
the maximally bonded sector is the
close-packed one. The contact maxima
3n 5
,
3n 4
,
3n 3
at
n = 10, 11, 12
exceed
the construction bound
3n 6
and reproduce the known maximal-contact clusters of
hard spheres with short-range attraction, which are subsets of close-packed crystals [10].
Concentration on maximal
B
cont
would therefore be concentration on close packing. What
is missing is not the identication of the maximizers, which is enumerated at every size
computed, but the decit-entropy bound in the embedded state space and its control as
n
.
Status of what follows.
The geometric results below, the identity metric of Section 3.8,
the exact isotropy of Section 4, the code of Section 5, and the whole of Part II, rest on the
close-packed phase. Three independent lines support the assembly reaching it: contact-
maximizing congurations are close packings wherever enumerated; the growth simulation
of Ref. [22] reaches a bulk of modal coordination
K=12
directly; and
K=12
is a forced
terminus of any growth history under the exclusion window, by the kissing bound (Part II,
Section 15), independently of any energy function. None of the three is a thermodynamic
concentration theorem for
M
emb
, and we do not claim one.
4 Exact spatial isotropy of the close-packed bond set
A persistent objection to discrete spacetime models is the apparent incompatibility be-
tween lattice regularity and continuous Lorentz invariance. If the 3D FCC lattice were
a foundational background, it would possess preferred directions (the crystallographic
axes), leaving the framework vulnerable to the Collins et al. naturalness objection [15],
which highlights that radiative corrections amplify even small tree-level Lorentz violations
into macroscopic, experimentally falsiable anomalies. We address this in three steps, an
exact algebraic isotropy of the FCC bond set at the lattice level, the resulting isotropy
of the scalar lattice dispersion at long wavelengths, and the conditions under which a
Lorentz-invariant continuum limit follows, confronted with experimental bounds.
Step 1: Exact spatial isotropy of the FCC bond set.
The
K = 12
FCC nearest-
neighbor bond vectors are
n
j
(±1, ±1, 0), (±1, 0, ±1), (0, ±1, ±1)
/
2, j = 1, . . . , 12.
(14)
Dene the rank-2 structure tensor
S
µν
P
12
j=1
n
µ
j
n
ν
j
. By direct enumeration:
S
xx
= 4 ×
1
2
|{z}
(±1,±1,0)
+ 4 ×
1
2
|{z}
(±1,0,±1)
+ 0
|{z}
(0,±1,±1)
= 4,
(15)
S
xy
=
1
2
(+1)(+1) + (+1)(1) + (1)(+1) + (1)(1)
+ 0 + 0 = 0,
(16)
and the three-fold permutation symmetry of the bond set gives
S
yy
= S
zz
= 4
and
S
xz
= S
yz
= 0
. Therefore
S
µν
= 4 δ
µν
(exact, by enumeration)
.
(17)
14
This algebraic identity guarantees equal propagation speed in every spatial direction for
the scalar sector at leading order in
k
. The odd-rank tensor
T
µνλ
P
j
n
µ
j
n
ν
j
n
λ
j
vanishes
exactly because the FCC bond set is centrosymmetric: every
n
j
has a partner
n
j
, so all
odd-power sums cancel,
T
µνλ
= 0
(exact, by inversion symmetry)
.
(18)
Equation (18) forbids any preferred direction and any linear-in-
k
term in the lattice dis-
persion.
Step 2: Isotropy of the dispersion relation.
For a scalar eld on the FCC lattice, the
dispersion relation is
ω(k)
2
= κ
P
12
j=1
1 cos(k · n
j
a)
. At long wavelengths (
|k|a 1
),
expanding the cosine,
ω(k)
2
κa
2
2
12
X
j=1
(k · n
j
)
2
=
κa
2
2
k
µ
k
ν
S
µν
= 2κa
2
|k|
2
,
(19)
so
ω = c
s
|k|
with
c
s
= a
p
2κ/m
, where
κ
is the bond stiness that xes rigidity in
Part II and
m
the node inertia. This scalar speed is the
trace
channel of the displace-
ment dynamics. The three acoustic branches of the full vector (phonon) problem satisfy
v
2
L
+ v
2
T
1
+ v
2
T
2
= c
2
s
in every propagation direction (Part II, Section 23), so
c
s
is the
quadrature sum of the branches rather than the speed of any single polarization. The
dispersion is exactly isotropic at leading order. This isotropy is an algebraic consequence
of equation (17), not an approximation. Anisotropic corrections to the scalar dispersion
enter at relative order
(|k|a)
2
, the
[111]
[100]
splitting of
ω
2
is
(|k|a)
2
/72
at leading
order, suppressed by
(E/M
P
)
2
for Planck-scale lattice spacing
a
P
.
Step 3: Emergence of Lorentz boosts.
The isotropy (17) guarantees equal prop-
agation speed in every direction for any
scalar
excitation on the bond set. That is the
geometric prerequisite for emergent Lorentz invariance. Vector (displacement) excitations
behave dierently. They are governed by the rank-four bond tensor and remain direction-
and polarization-split at the lattice scale (Part II, Section 23).
The causal cone itself is carried by the propagating bond excitation, whose signal speed
c
is derived in Part II. The elastic speed
c
s
above is a distinct, metric-perturbation mode. A
single light cone therefore requires
c
s
= c
. That equality is not a tuning but an observed
fact: gravitational-wave and photon speeds agree to one part in
10
15
. Part II shows that
imposing it on the elastic trace channel xes the stiness
κ
, while the sharper branch-level
statement remains an open target. Given one cone, an isotropic linear dispersion yields a
relativistic eective eld theory in the standard continuum limit [15].
Confronting the experimental bounds.
Lattice corrections at the cuto scale
1/a
are
suppressed by
(E/M
P
)
2
and lie far below all current experimental bounds on Lorentz vio-
lation [16, 17], which constrain departures at the level of
10
20
10
40
of the Planck scale.
Given a single propagation speed, spatial
SO(3)
isotropy and time-reversal symmetry
force the dimension-4 kinetic operators of the
scalar
sector into Lorentz-invariant form;
sectors with distinct speeds (the elastic branches of Part II) remain Lorentz-violating until
the branch-level cone closes, and protection of the invariance against radiatively gener-
ated lower-dimension Lorentz-violating operators [15] is an open requirement instead of
a result obtained here.
15
Residual
O
h
anisotropy is absent from the
scalar
sector at leading order by Eq. (17); in
the vector (elastic) sector it is physical, the rank-four bond tensor splits directions and
polarizations (Part II, Section 23), and is not a coordinate artifact.
Polycrystalline averaging as a complementary mechanism.
While equations (17)
(19) guarantee macroscopic isotropy from a single FCC domain, a secondary classical
mechanism reinforces it. Because the kinematic growth is probabilistic, the vacuum nu-
cleates multiple independent planar domains. As they expand and meet in 3D space, their
FCC registries misalign, creating a polycrystalline structure with randomly oriented grain
boundaries. Table 2 of Ref. [22] reports the macroscopic shape isotropy
λ
min
max
of the
spatial covariance matrix
C
ij
= (x
i
¯x
i
)(x
j
¯x
j
)
. The ratio rises steadily from 0.39 at
N = 250
to 0.54 at
N = 1000
(30 seeds), conrming that while individual stochastically
grown grains possess shape bias, the ensemble rapidly spherizes, a classical bulk-averaging
mechanism that complements the exact algebraic isotropy of equation (17).
5 The
[[192, 130, 3]]
CSS Code
An ideal bulk patch of the emergent FCC lattice carries a mathematically veriable quan-
tum error-correcting code. The code is dened on a defect-free
4×4×4
unit-cell arrange-
ment with periodic boundaries, the single-crystal idealization of the polycrystalline clus-
ters grown here, whose grain boundaries and free surfaces host unclosed stabilizers, with
192 edges, each treated as a physical qubit. In the CSS construction of [13], X-stabilizers
act on octahedral voids (each touching the 12 edges connecting its 6 surrounding vertices)
and Z-stabilizers act on vertices (each touching the 12 incident edges); both families have
uniform weight 12. The code parameters, veried computationally in [21], are:
Physical qubits (
n
) 192 (edges of the FCC lattice)
Logical qubits (
k
) 130
Code distance (
d
) 3
Encoding rate (
k/n
) 67.7%
Vertices (
V
) 13 per coordination cluster
Edges (
E
) 36 per coordination cluster
Faces (
F
) 38 (
= 32
triangles
+6
squares)
The coordination cluster.
The 13-node coordination cluster, the central node together
with its 12 cuboctahedrally arranged neighbors, decomposes as a simplicial complex into
32 triangular 2-cells and 6 square 2-cells: 8 of the triangles are the cuboctahedron's surface
faces, and the remaining 24 are spoke triangles formed by each cuboctahedral edge with
the central node. The 32 triangles are the minimal closed gauge-invariant loops [6] that
underlie the compound-QEC argument of Section 2.4; the 6 squares, representing the
absence of a diagonal bond, are topologically distinct.
Why the rate is high.
The encoding rate
k/n = 67.7%
means two-thirds of the lattice
degrees of freedom carry logical information. By comparison, 2D topological codes on
planar or toroidal geometries encode a xed number of logical qubits regardless of system
size, so their rate
k/n 0
as
n
.
16
A triple coincidence at 3.
The 3D projection, rare as it is at
5%
per frontier site,
is what enables an extensive encoding rate. Three quantities coincide at the value 3: the
code distance
d = 3
, the number of independent distance constraints
S = 3
for the tetra-
hedral lift, and the ambient spatial dimension. Whether this triple coincidence reects
a structural identity or is accidental remains an open question that may be addressable
through a generalized construction at other values of
d
.
6 Conclusion
Summary.
Part I has taken the two local operators of the Selection-Stitch Model and
asked what structure they select. The stitch and lift are motivated as the minimal ways to
create new closure at xed bond length, and closure is what allows a correlation to persist
at all. Their relative amplitude
e
3
is motivated by the codimension dierence between
their solution manifolds and by the error-correction reading of Section 2.3; Part II derives
it as a thermal factor with a free geometric prefactor.
Principal results.
1. The assembly is a reversible Markov process on pre-geometric bond complexes, with
stationary measure
π
N
e
βεB
and, under a removable-node condition, a unique limit
from any initial state (Section 3.2).
2. Where the decit-sector counts obey an exponential bound and
βε > s
, that mea-
sure concentrates exponentially on maximally bonded complexes (Section 3.4).
3. Exhaustive enumeration through
N = 8
conrms connectivity, reversibility, detailed
balance and stationarity to residuals below
7×10
18
, and measures the decit-sector
entropy rather than assuming it (Section 3.6).
4. Kinetic suppression of the lift leaves the stationary measure unchanged, veried at
ρ = 1
,
0.1
and
e
3
. The lift amplitude is kinetics; the bond energy xes equilibrium.
5. The construction and contact bond counts share their maximizers through
n = 9
and separate from
n = 10
, where contact maximizers acquire the octahedral cells
that all-lift histories cannot produce and reproduce the known maximal contact
numbers of hard-sphere clusters (Section 3.7).
6. The local bond second moment of a close packing is
S
µν
= 4δ
µν
, so the reconstructed
spatial metric is the identity (Section 3.8); the same bond set is exactly isotropic
at rank two and centrosymmetric at rank three (Section 4). These are statements
about the close-packed conguration, not consequences of the measure above.
Limits of these results.
The results above are established for the history-resolved model
M
hist
. Detailed balance carries over algebraically to the embedded model
M
emb
that the
physical energy denes; ergodicity, the decit-entropy bound, and hence concentration
do not, because they were veried on a dierent state space (Table 2). The two models
share their maximizers over the range enumerated, and maximal contact bonding is close
packing at every size computed, but a thermodynamic concentration theorem for
M
emb
is open (Section 3.9). Contact maximization selects close packing but not the stacking
17
isomer: FCC versus HCP is settled in Part II (Section 16), by an argument that needs no
energy function. And the construction is positional throughout, a limitation taken up in
Part II (Section 26).
The emergent lattice supports the
[[192, 130, 3]]
CSS code of Ref. [21], whose distance
d = 3
matches the suppression exponent under the survival ansatz of Section 2.3. Part II
supplies the dynamics: a bond Hamiltonian whose dissipative limit assembles the lattice
and whose coherent limit propagates a signal cone on it.
Part II
Dynamical Foundations
7 The dynamical framework: an overview
The SSM posits that the vacuum is a close-packed network of entanglement bonds that
crystallizes from a frustrated tetrahedral foam (
K=4
) into a face-centered cubic (FCC)
close packing (
K=12
). Part I formulates the stitchlift rules as a reversible Markov process
and shows that its stationary measure concentrates on maximally bonded structures,
veried exactly on the history-resolved state space. It also shows that a close packing
carries a at isotropic spatial metric and an explicit quantum error-correcting code, the
[[192, 130, 3]]
CSS code, and that maximal contact bonding is close packing at every size
enumerated (Section 3.9). Part II takes the close-packed lattice as given, except where
noted.
The contribution of Part II is the dynamical law beneath that assembly; the branching-
growth material in Section 20 is a structural outlook, clearly secondary to the forced-
K=12
assembly that is the main result.
Part I xes the
kinematics
: which moves occur, and what they build. It does not supply
the
dynamical law
. That law requires a Hamiltonian whose evolution generates both the
growth and the propagation of signals, a physical clock and ruler, a
derivation
of the
stability that holds the crystal, and an account of what is forced, what is free, and what
scale the model must supply. Part II supplies all of these in one place.
The organizing result.
One open-system equation (Figure 1) governs the vacuum:
its coherent limit propagates an emergent light cone and its dissipative limit assembles
the lattice, with the kinematic growth represented by a geometry-conditioned trajectory
picture.
Three features settled.
Along the way we settle three implicit features of the simu-
lation. The
K=12
terminus is forced by the kissing-number bound (Section 15). The
lift rate factorizes into a free geometric acceptance and a thermal factor
e
3
xed by
T
0
= ε
(Section 17). And the parameter the model requires is a rigidity scale, derived
self-consistently from the phonon spectrum (Section 18). Sections 2416 give the energy
ladder, the code, and the FCC-over-HCP selection. The stitchlift construction and the
[[192, 130, 3]]
code are set out in Part I; the geometric maxima use the kissing-number [18]
18
and Kepler [3] theorems.
An emergent-geometry reading.
The results assemble, step by step, the features
we associate with physical space on a single self-organizing substrate: spatial isotropy
from the close-packed coordination and a causal signal cone from the local Hamiltonian
(Section 12), and a transient constant Regge curvature carried by the two-sheet foam
(Section 9).
The program, and its boundary.
In this sense Part II is a program for
emergent
geometry
: the lattice does not sit in space, it
is
the space, and its geometric, causal,
and cosmological properties are consequences of the assembly dynamics instead of inputs.
The boundary of the program is that the dynamics is still
positional
, it presupposes that
the nodes carry positions in a metric, with a hard-core exclusion, so the deepest step,
deriving those positions from the entanglement data themselves, is not yet taken. Part II
establishes the geometric and cosmological
features
of emergent space and leaves the
emergence of the positional substrate as the frontier.
Status of the claims.
The results below sit at dierent condence levels, and they are
labeled throughout.
(T) Theorem-level
: the forced
K=12
terminus and
R
=
p
2
2 L
(Section 15), which depend only on geometry.
(D) Derived and robustly tested
: the
detailed-balance stability
q = 1/(1 + e)
and the end-to-end coherence of the assembly,
which we conrm reaches bulk
K=12
generically across temperature (Section 21).
(C) Consistent but separately grounded
: the light cone and the relation
c = 4
2 v
lat
,
which follow from the posited Hamiltonian and are mutually consistent but are not inde-
pendently tested here.
(C/D) Numerically derived, conditional on the posited dynamics
:
the rigidity bounds of Section 18, obtained by Brillouin-zone integration of the FCC
phonon spectrum.
(S) Speculative
: the exponential branching-growth phase (Section 20).
Contributions.
Part II develops the close-packed vacuum from its dynamical law: the
open-system Hamiltonian and master equation; the single-excitation signal cone and
c =
4
2 v
lat
; the detailed-balance derivation of
q = 1/(1 + e)
; the forced
K=12
terminus and
the exact threshold
R
; the factorization of the lift rate into a free geometric acceptance
and a xed thermal factor
e
3
; the rigidity scale
κ 36 ε/L
2
; the end-to-end single-rule
assembly and its temperature robustness; the two-sheet tetrahedral foam and the code
selection of its regular registration; and the exponential branching-growth phase.
The conceptual starting point, the stitchlift picture of the vacuum as an incompletely
crystallized close packing, together with the
[[192, 130, 3]]
code construction, is developed
in Part I; the contact maxima rest on the kissing and Kepler theorems [18, 3].
19
Lindblad master equation
˙
ρ
=
i
[
H, ρ
] +
X
b
(
γ
D
[
σ
+
b
] +
γ
D
[
σ
b
])
ρ
coherent limit
bath off:
˙
ρ
=
i
[
H, ρ
]
unitary evolution
light cone,
v
= 2
`
lat
ε/
dissipative limit
thermal jumps at
T
0
=
ε/k
B
quantum-trajectory assembly
growth,
q
=
1
1 +
e
one dynamics, two limits
Figure 1: One open-system Hamiltonian, several sectors: Eq. (21) coupled to a thermal
bath at
T
0
= ε/k
B
. Coherent limit
ballistic signal front and the collective sectors of
Table 5; dissipative limit
constructive assembly with detailed-balance rate
q = 1/(1+e)
.
8 Foundational assumptions
Foundational assumptions.
Before the dynamics, we state the premises the construc-
tion rests on, so that what is assumed is separated from what is derived.
(A1) A pre-
geometric substrate.
The starting arena is not space but a structureless set of pre-spatial
degrees of freedom carrying entanglement; metric notions (distance, direction) are not
assumed to pre-exist but are intended to emerge from the bond network. In Part II the
substrate is treated
positionally
, the admissible congurations already carry a length
L
(Section 14, Eq. (31)), and a fully pre-positional formulation, in which
L
itself emerges,
is left as the frontier (Section 26).
(A2) Bell-pair nucleation at a unit rate.
The elementary event is the formation of a
maximally entangled bond (a Bell pair) between two substrate elements, occurring at a
xed nucleation rate that sets the unit of time and a xed bond length
L
that sets the
unit of length. All rates and lengths in Part II are expressed in these units; the model
xes their dimensionless ratios, not their absolute values (Section 22).
(A3) Stability selected by error correction.
A nucleated structure persists only if it is
stabilized, a conguration survives in proportion to how well its bonds close into the
stabilizer cells of the emergent code, and decays otherwise. This is the principle behind
the dissolution ratio
q = 1/(1+e)
(Section 13) and the selection of the regular registration
(Section 9): among competing local structures, those whose stabilizers are satisable are
the ones that live. The structural lattice carries the
[[192, 130, 3]]
CSS code on its edges.
(A4) One binding scale.
Every bond has the same binding depth
ε
, the single energy
parameter of the Hamiltonian (Section 10).
What follows from them.
From these
four premises, a pre-geometric entangled substrate, unit-rate Bell-pair nucleation, code-
selected stability, and one binding scale, the rest of Part II is a consequence.
Part I establishes the kinematics on which these premises act. They are the stitch and lift
operators, the cascade
K=1 6 4 12
through a frustrated
K=4
foam with Regge
decit
δ = 2π 5 arccos
1
3
7.36
(Eq. (1)), and the
K=12
saturation at the Kepler
20
bound. We treat them here as the classical limit of the dynamics and do not repeat them.
One further premise is inherited and should be stated with the others. Most of Part II
works on the close-packed lattice: the acoustic spectrum, the rigidity bound, the code, the
metric, and the FCC-over-HCP selection all take that lattice as given. Part I supports it
three ways, maximal contact bonding is close packing at every size enumerated, the growth
simulation of Ref. [22] reaches a modal
K=12
bulk directly, and the thermodynamic-limit
concentration statement remains open (Section 3.9).
Section 15 is the exception and does not inherit this premise. It bounds coordination for
any
unit-bond conguration under the exclusion window, by the kissing-number theorem,
so it constrains the close packing rather than presupposing it.
9 Code-selected registration and the two-sheet foam
The dynamics below need two features of the close packing that Part I does not address:
how the layer-by-layer arrival of sheets produces a transient, spatially homogeneous cur-
vature, and why the code selects the regular FCC registration over its competitors. Both
are developed here.
The two-sheet tetrahedral foam.
A structural question worth settling is
where
the
tetrahedral decit lives during crystallization. Sheets arrive one at a time: a sheet is
seeded by a lift and grows laterally, and the next sheet is independently seeded and
grows, so there is always a nite delay between the arrival of consecutive sheets. During
that delay the structure is in a
two-sheet
state, and the two-sheet state is tetrahedral.
Verifying the two-sheet geometry.
We check this directly. Stack two at
K=6
sheets
at the close-packed oset and spacing
h =
p
2/3 L
. Every interior node of the lower
sheet then bonds to its six in-plane neighbors and to three nodes of the sheet above,
giving coordination
K=9
. That node, together with the triangle above it, forms a
regular
tetrahedron
, with all six edges equal to
L
. This holds for
100%
of interior nodes in a nite
patch. The frustrated tetrahedral bonding here is the same that denes the
K=4
foam of
the cascade (Section 2.1). The count
K=9
simply includes the six in-plane sheet bonds
alongside the four-coordinated tetrahedral motif. The two-sheet contact therefore realizes
the tetrahedral foam as an extended, registered layer instead of a disordered bulk.
Why the decit takes a xed value.
A new sheet can be seeded only where the
lifted apexes project to
equidistant
points, since those apexes must themselves form the
next
K=6
sheet. We verify that the apexes of the lifted up-triangles do form a regular
triangular lattice, at nearest-neighbor spacing
1.00 L
.
This seeding constraint, together with the code stabilizers that hold the sheets rigid
(Section 25), forces the tetrahedra to remain
regular
rather than relax to an irregular
packing. The frustration is paid as curvature, not absorbed by distorting the bond angles.
That the code prefers this registration is computed, not assumed. Table 3 compares
three candidate stackings of the second sheet: the regular close packing, the eclipsed
(AA) stacking, and a relaxed irregular packing. The measure is the fraction of triangular
plaquettes that are genuine cell faces, that is, the fraction of
Z
-stabilizers that can be
21
Table 3: Comparative code metrics for three registrations of the second sheet onto the
rst (a
50
-node patch). Faced is the fraction of triangles that are faces of a tetrahedral
cell, the fraction of plaquette (
Z
) stabilizers that can be consistently satised. Only the
regular close packing forms tetrahedra and closes its stabilizers, so the code selects it.
registration tetrahedra faced fraction edge irregularity stabilizers satisable
regular (FCC)
32 0.73 0.000
maximal
eclipsed (AA)
0 0.00 0.000
frustrated
relaxed (irregular)
0 0.00 0.068
frustrated
consistently satised. (Note that at the close-packed spacing
p
2/3 L
an eclipsed second
sheet is excluded outright by the hard core, aligned nodes sitting at
0.8165 L < R
ex
; the
eclipsed row is therefore meaningful only at unit vertical spacing.)
FCC versus HCP: what selects the stacking.
Local
K=12
packing admits two reg-
istrations: cuboctahedral (FCC, ABC) and anticuboctahedral (HCP, ABAB). At nearest-
neighbor level they are
exactly
degenerate. Direct enumeration shows both coordination
shells contain 24 unit-distance pairs and 8 unit triangles. The pair energy is therefore
blind to the dierence, and so is any three-body triangle term
H
3
= J
3
P
n
ij
n
jk
n
ki
.
Selection must come from structure the shells do not share. There are three candidates.
(i) Couplings at second-neighbor range and beyond, where the two stackings' distance
spectra rst dier. (ii) The void geometry: HCP's octahedral voids share faces along
the
c
axis, while FCC's share only edges, so the octahedral
X
-stabilizers of the emergent
code see inequivalent environments. This makes the code term itself a candidate selection
energy. (iii) The vibrational free-energy split
F = E T S
vib
, known to be minute
for central-force packings.
Computing the code-term split is a dened target calculation. A fourth possibility, which
does not appear in this list because it is not an energy at all, is that the stacking is
xed kinematically by an orientation the growth front transports; that is the argument of
Section 16. Pending the code-term calculation and the classier follow-up noted in Part I,
the result stands as close packing with a candidate selection mechanism. Only the regular
registration forms tetrahedral cells at all (
32
versus none) and closes its plaquettes (
73%
faced versus
0%
); the alternatives are stabilizer-frustrated.
What the comparison establishes.
Among the candidates compared, the regular
close-packed registration maximizes the satisable stabilizers, which is what selection by
the code means operationally, with the caveat that FCC and HCP are
both
regular close
packings, and Table 3 does not compare them against each other; the table establishes
close-packed over eclipsed or irregular registration, and the FCC/HCP split is the separate
question addressed below. (This is a stabilizer-satisability comparison across the physical
competitors, a structural proxy for code distance instead of a full distance calculation;
the margin is wide enough that the conclusion is insensitive to the proxy.)
The decit is homogeneous.
Five regular tetrahedra about a hinge subtend
5 arccos
1
3
= 352.64
, leaving exactly the Regge decit
δ = 2π5 arccos
1
3
= 7.36
(Eq. (1));
a relaxed, irregular foam would instead distribute a much larger and variable decit. Be-
cause the seeding-plus-code constraint enforces the
same
regular registration everywhere
22
δ
= 7
.
36
Five regular tetrahedra about a hinge:
frame held rigid, frustration
=
δ
= 7
.
36
apexes are equidistant
next regular sheet
each apex caps one triangle
(3 bonds, regular tetra)
Seeding: one apex per up-triangle; the apexes,
being equidistant, form the next regular sheet
Figure 2: Left: the xed value of the decit. Five
regular
tetrahedra about a shared
hinge subtend
5 arccos
1
3
= 352.64
, leaving exactly the Regge gap
δ = 7.36
. The code
stabilizers forbid the tetrahedra from relaxing to an irregular packing (which would give
a larger, variable decit), so the frustration is paid as curvature at this single value.
Right: why the registration is regular. A new sheet seeds only where the lifted apexes
(red) are equidistant, forming the next
K=6
sheet; the apexes of the lifted up-triangles
do form a regular lattice (spacing
1.00 L
), so seeding plus code-enforced rigidity hold
the same regular tetrahedral registration everywhere along the contact. The decit is
therefore spatially homogeneous and xed at
δ
, and vanishes when the third sheet closes
the cuboctahedral shell (
K=9 12
).
along the contact, the decit is spatially homogeneous and takes this single xed value
(Figure 2). The third sheet converts
K=9 12
and the decit vanishes exactly, the
cuboctahedral shell tiling space without frustration. The cancellation is not approximate.
The completed packing is the tetrahedraloctahedral honeycomb, in which two tetrahe-
dra and two octahedra meet at every edge with supplementary dihedral angles, so the
angles about an edge sum to
2π
identically (Section 16). The frustration of the two-sheet
stage is precisely the absence of the octahedral cells that supply the complementary angle.
The crystallization therefore passes through a genuine, spatially extended, nite-duration
tetrahedral foam:
at sheet
(K=6, δ=0)
two-sheet foam
(K=9, δ>0,
homogeneous
)
FCC
(K=12, δ=0).
(20)
The foam is therefore not an assumption: it is the two-sheet stage that layer-by-layer
arrival necessarily produces, and it carries a homogeneous decit for a nite interval
before the third sheet closes the shell.
Claim ledger.
Table 4 summarizes the principal claims of both parts and their status,
so that the results proved for the stated model can be separated at a glance from those
conditional on it. Tiers:
(T)
theorem-level;
(D)
derived and numerically tested;
(C)
consistent within the posited dynamics;
(S)
speculative. A slash denotes intermediate
standing:
(C/D)
is numerically derived but conditional on the posited dynamics, and
(D/S)
is derived but with speculative interpretation.
23
Table 4: Claim ledger. Upper block: Part I. Lower block: Part II. The reversibility of
the chain and the forced
K=12
terminus are the theorem-level results; everything below
them is conditional on the posited dynamics or on a bound veried only at small size.
Claim Status Basis
detailed balance,
π
e
βεB
T MetropolisHastings; algebraic,
holds for
M
hist
and
M
emb
alike
ergodicity, unique sta-
tionary limit
D removable-node condition; veried
for
M
hist
,
N 8
lift suppression is kinet-
ics, not equilibrium
D exact, veried at
ρ = 1, 0.1, e
3
on
every enumerated state space
concentration,
M
hist
C/D exact given the decit-entropy
bound; bound measured only for
N 8
maximal
B
cont
= close
packing
D enumerated for
n 12
; matches
maximal-contact hard-sphere clus-
ters [10]
concentration,
M
emb
S open. Ergodicity and decit en-
tropy not established on the em-
bedded space
K=12
forced for
R
<
R
ex
< L
T cuboctahedral square-face vacancy
+ kissing bound
q = 1/(1 + e)
D detailed balance at
T
0
= ε/k
B
robust modal
K=12
as-
sembly
D end-to-end stochastic rule,
temperature-generic
e
3
lift suppression C thermal factor at the operating
point
βε = 1
; geometric prefactor
free; QEC reading heuristic
κL
2
36 ε
rigidity C/D FCC harmonic phonon estimate
10 The dynamical Hamiltonian and its scales
Let each potential bond
b
be a qubit,
|1
b
entangled (energy
ε
) or
|0
b
failed (
0
),
n
b
=
|1⟩⟨1|
b
:
H = ε
X
b
n
b
Γ
X
b,b
1
2
(X
b
X
b
+ Y
b
Y
b
) ε
h
X
v
A
v
+
X
o
B
o
i
, Γ = ε.
(21)
The
binding
term rewards each entangled bond; the
kinetic
term lets entanglement hop
between bonds sharing a node and makes
H
generate motion; the
code
term is the CSS
stabilizer Hamiltonian (Section 25),
A
v
=
Q
bv
Z
b
,
B
o
=
Q
bo
X
b
. The bond-state Hamil-
tonian has a single binding depth
ε
(and we set the kinetic coupling
Γ = ε
); as Section 18
shows, the
positional
realization of the bond requires in addition a curvature scale
κ
,
distinct from the depth. The constants
ε
and
L
yield
τ
0
=
ε
, v
lat
=
L ε
, T
0
=
ε
k
B
.
(22)
24
11 The open-system dynamics
An entangled bond decoheres against its environment, and that decoherence
is
bond
failure; the dynamics is Eq. (21) coupled to a thermal bath at
T
0
= ε/k
B
:
˙ρ =
i
[H, ρ] +
X
b
γ
D[σ
+
b
] + γ
D[σ
b
]
ρ, D[L]ρ = LρL
1
2
{L
L, ρ}.
(23)
Two limits supply the two halves of the physics: bath o, unitary evolution gives the light
cone (Section 12); bath on, thermal jumps drive assembly (Sections 13, 14).
What the bath is, before geometry.
The bath requires explanation: if the lattice is
the vacuum, what constitutes a thermal environment when there is no space yet to host
one? We take the bath to be the reservoir of
unentangled, unregistered degrees of freedom
,
the bond qubits that have not (yet) joined the coherent network, i.e. the population in the
|0
(failed) state and the latent bonds of the surrounding foam. These are not external
to the vacuum; they are its own pre-crystalline part. Decoherence of an entangled bond
against this reservoir of un-joined bonds is precisely bond failure, and the temperature
T
0
= ε/k
B
is the statistical scale of that reservoir (one bond carries entropy
ln 2
).
A self-bath.
The crystallizing network and the foam it grows into are the system and
the environment for each other. It is therefore pre-geometric in the required sense, no
external spacetime is invoked, though a fully pre-positional formulation, in which even
the reservoir carries no presupposed positions, remains open (Section 26).
12 Coherent limit: a single-excitation signal cone and
lattice isotropy
The front speed.
In the single-excitation sector the kinetic term is tight binding on
the bond-adjacency (line) graph of the lattice. A localized excitation therefore spreads
ballistically (Figure 3). On a one-dimensional bond chain the front velocity is
2Lε/ =
2v
lat
, veried as
2.01 Lε/
on
401
bonds. On the FCC bond network the front is faster.
For a
K
-regular lattice the line-graph band is the node-graph band shifted by the constant
K 2
, so the maximum group velocity is that of tight binding on the FCC nodes:
v
front
= 4
2 v
lat
5.66 v
lat
,
(24)
attained for
k
along
[100]
, where the eight bonds with a
[100]
component give
|∇E|
max
=
4
2 ΓL
.
How to read this speed.
Being a band-structure extremum, the front speed is direction-
dependent at the lattice scale. The ballistic wavefront is not spherical; only the long-
wavelength scalar sector is isotropic (Section 4). We therefore give the bound its precise
name:
v
sig
4
2 v
lat
is the
maximum microscopic signal velocity
of the hopping sector.
It is a causal bound, not a low-energy propagation speed. The hopping band is quadratic
at long wavelength,
E(k) = E
0
+ A|k|
2
+ O(k
4
)
, so the group velocity of long-wavelength
25
Table 5: The three propagation sectors of the lattice. One symbol
c
hides three inequiv-
alent speeds; this table keeps them separate.
Sector Excitation Dispersion Status
Bond hopping
H
hop
localized bond
excitation
quadratic at low
k
; bal-
listic front bounded by
v
sig
= 4
2 v
lat
, direction-
dependent
derived
Scalar collective
H
ϕ
emergent scalar
eld
linear and isotropic as
k 0
, speed
c
ϕ
= c
s
identied here
(trace channel)
Elastic
H
u
displacement
modes
linear but polarization-
split,
v
L
= v
T
1
, v
T
2
derived; single cone
closed by no-go
(Section 23)
bond excitations vanishes as
k 0
. The genuinely
linear
low-energy cone belongs instead
to the scalar collective sector: a lattice eld with canonical pair
(ϕ
i
, Π
i
)
and Hamiltonian
H
ϕ
=
1
2
X
i
Π
2
i
+
K
ϕ
2
X
ij
(ϕ
i
ϕ
j
)
2
, ω
2
(k) =
K
ϕ
m
ϕ
X
j
1 cos(k · a
j
)
,
(25)
whose small-
k
dispersion is
ω
2
= c
2
ϕ
k
2
+ O(k
4
)
with
c
ϕ
= L
p
2K
ϕ
/m
ϕ
, exactly the trace-
channel speed
c
s
of the displacement dynamics when
K
ϕ
= κ
,
m
ϕ
= m
. The status of this
sector is as follows. The close-packed geometry
supports
an additional scalar collective
eld with an isotropic linear continuum limit. It does not yet derive one. Obtaining
ϕ
i
as a collective coordinate of the bond qubits, schematically
ϕ
i
P
bi
f(n
b
)
, with
H
ϕ
from coarse-graining Eq. (21), is the dened target that would make the sector emergent
rather than adjoined. Table 5 collects the three sectors and their status. The single-cone
problem is then exactly the question of whether
c
ϕ
= v
T
= v
L
can be arranged, which
Section 23 answers. A local Hamiltonian has a nite LiebRobinson velocity. Time and
length combine into a maximum signal speed for excitations on the lattice. This is a single-
excitation, LiebRobinson-type signal cone, not a derivation of the full relativistic causal
structure of a continuum eld theory (Section 26). This is the dynamical counterpart
of the structure-tensor isotropy: the twelve bond vectors give
S
µν
=
P
j
n
µ
j
n
ν
j
= 4δ
µν
and
T
µνλ
= 0
by centrosymmetry, so the long-wavelength scalar dispersion is isotropic,
with anisotropy entering only at relative order
O((|k|L)
2
)
(coecient
1/72
; Section 4).
The causal cone is the signal front itself:
c v
front
= 4
2 v
lat
= 4
2 Lε/
, the fastest
speed at which any inuence propagates on the lattice.
Notation and its limits:
we write
c
for this lattice signal bound throughout Part II. It is a bound internal to the model.
The model xes no absolute velocity, because
v
lat
= Lε/
depends on
L
and
ε
, which
assumption A2 leaves unxed; every speed below is a dimensionless ratio in which they
cancel. Reading
c
as the physical speed of light is a further identication, conditional on
the GW
=
light constraint below and unresolved at branch level (Section 23). Here the
clock is
τ
0
=
and the ruler
L
. This bond-excitation cone is the model's causal cone,
and is what we mean by the emergent light cone. It is distinct from the elastic phonon
speed
c
s
= L
p
2κ/m
, which propagates metric perturbations instead of signals.
Fixing the stiness.
A single, shared cone is not optional. The measured equality
of the gravitational-wave and photon speeds to one part in
10
15
[20] requires the elastic
26
and signal cones to coincide; imposing this on the elastic trace channel,
c
s
= c
(see the
mode-speeds paragraph below), xes the otherwise-free stiness,
κ =
mc
2
2L
2
=
16
2
2
(
GW
=
light, trace channel
: c
s
= c).
(26)
A oor on the binding scale.
The rigidity requirement
κL
2
36 ε
of Section 18
sharpens this. The two together impose a oor on the binding scale,
ε 2.3
2
/(mL
2
)
,
the bond energy cannot lie below the lattice kinetic scale
2
/(mL
2
)
. Equal cones, in this
trace sense, thus x a stiness that would otherwise be free; the branch-level statement
remains the open target recorded in Section 23.
Mode speeds and the single cone.
The cone
c = 4
2 v
lat
used here is the Lieb
Robinson front of the scalar bond excitation on the FCC bond network. It is a distinct
object from the elastic branch
c
s
= L
p
2κ/m
. The rst is a band-structure maximum of
the signal sector; the second is the long-wavelength sound speed of the displacement eld.
Section 4 established one necessary geometric ingredient of emergent
SO(3, 1)
invariance:
the exact bond-set isotropy
S
µν
= 4δ
µν
and centrosymmetry
T
µνλ
= 0
, which force a
rotationally isotropic scalar kinetic term at leading order. That result is conditional on
a common propagation speed. It is an ingredient, not the invariance itself. Part II asks
whether the common speed can be supplied dynamically.
The GW
=
light identication, Eq. (26), forces the elastic
trace
speed to coincide with
the signal front,
c
s
= c
. This is weaker than the branch-level statement the observation
constrains. The three elastic polarizations satisfy
v
2
L
+ v
2
T
1
+ v
2
T
2
= c
2
s
in every direction
(Section 23). Fixing
c
s
= c
therefore places the branches at
c
only in quadrature mean.
The individual polarizations remain sub-luminal and split:
v
L
[0.71, 0.82] c
and
v
T
[0.35, 0.50] c
.
The gap to a genuine single cone cannot be closed within the elastic sector at all, by
the no-go results of Section 23. Three-body angular terms can restore isotropy, but not
speed equality, which requires a distinct excitation sector. We therefore do not derive
the stronger statement that every sector and polarization shares this cone without the
GW
=
light input. We take
c 4
2 v
lat
as the causal cone of the signal sector, and state
the multi-speed structure explicitly rather than hiding it in a single symbol.
13 Dissipative limit: the assembly rate is derived
The entangled state lies
ε
below the failed state, so detailed balance requires
γ
=
e
ε/k
B
T
0
. In general
q(β) = 1/(1 + e
βε
)
, or
q = [1 + (g
1
/g
0
) e
βε
]
1
with bound and unbound
degeneracies
g
1
, g
0
, taken equal here.
We then set the operating point
βε = 1
. This is a stated identication of the bath
temperature with the bond scale, not a derived equality. Deriving the bath temperature
self-consistently from reservoir thermodynamics, via
T
1
= S
foam
/∂E
foam
, is the open
route to replacing this operating point with an equilibrium condition. At
βε = 1
the
27
200 150 100 50 0 50 100 150 200
position
x / `
lat
0
10
20
30
40
50
60
70
80
time
t /
(
/ε
)
v
= 2
`
lat
ε/
Emergent light cone from real-time evolution
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
log
10
|
ψ
|
2
Figure 3: Coherent limit: a bond excitation on a one-dimensional bond chain spreads with
front velocity
v = 2Lε/
; on the full FCC bond network the corresponding LiebRobinson
front is
4
2 Lε/
(see text).
single-bond rate equation has stationary failure probability
q =
γ
γ
+ γ
=
1
1 + e
0.2689,
(27)
with no free parameter beyond the chosen operating point
βε = 1
: the detailed-balance
ratio at
T
0
= ε/k
B
, where the only scale is the bond entropy
S = ln 2
. A node loses
rigidity when
K 2
of its
K
bonds fail, so its dissolution probability is the binomial tail
P
dissolve
(K) =
K
X
j=K2
K
j
q
j
(1q)
Kj
= {0.61, 0.29, 0.048, 7.5×10
5
}, K = {3, 4, 6, 12}.
(28)
Stability rises steeply with coordination. The foam turns over while the
K=12
core is
eectively immortal. This relative stability is the detailed-balance content of Eq. (23),
not an input.
Geometry-resolved cross-check.
The rule behind Eq. (28) is that a node fails on
losing
K 2
of its
K
bonds. We can test it against a criterion built from the actual bond
geometry. Form the local stiness matrix
M
αβ
= κ
P
aB
ˆn
a,α
ˆn
a,β
over the surviving bond
set
B
, and declare the node stable only if
M
has full rank, so that
λ
min
(M) > 0
and the
survivors span three dimensions.
Exhaustive enumeration over survival patterns at
q = 1/(1 + e)
gives three results.
The tetrahedral
K=4
node.
Here the two criteria coincide
exactly
, both giving
P =
0.294
. Any three of the four tetrahedral directions span
R
3
, so rank failure is precisely
the loss of
K 2
bonds.
The cuboctahedral
K=12
node.
The rank criterion gives
1.6 × 10
3
against the
binomial
7.5 × 10
5
. The dierence comes from coplanar survival patterns, the four
hexagonal and three square equatorial sections of the cuboctahedron, which keep many
bonds but no out-of-plane stiness. Both values are negligible against the foam's
0.29
.
28
The planar
K=6
sheet node.
This is rank-decient out of plane for
every
survival
pattern. That quanties why sheets are metastable waypoints of the cascade instead of
termini: they are two-dimensionally rigid, with in-plane rank-2 failure at
1.5 ×10
2
, and
three-dimensionally soft.
The stability hierarchy driving the cascade is therefore robust to the choice of criterion,
and the simple
K 2
rule is exact at the tetrahedral bottleneck, where it matters most.
Adding a physical stiness threshold.
The bare rank test
λ
min
> 0
classies ar-
bitrarily oppy congurations as stable. A physical threshold
λ
min
> λ
c
tied to the
Lindemann window is more realistic: soft-mode uctuations
kT
c
< (L R
)
2
give
λ
c
= 1/(0.0551 × 36) 0.50
at
T
0
. This
widens
the hierarchy rather than eroding it.
At
λ
c
= 0.50
the tetrahedral node dissolves at
P = 0.714
, since it now requires all four
bonds, any three give
λ
min
=
1
3
< 0.50
. The cuboctahedral node stays at
8.5 × 10
3
.
The full-shell stinesses are
λ
min
= 4
for
K=12
against
4
3
for
K=4
. This joins the
dissolution rule and the rigidity bound of Section 18 into a single mechanical stability
criterion.
14 The assembly as a quantum-trajectory representa-
tion
A quantum-trajectory unraveling of Eq. (23) replaces the density matrix by stochastic
paths with bond-creation (
σ
+
) and bond-destruction (
σ
) jumps; the stitchlift growth is
one such path (Algorithm 1). Births are
σ
+
jumps placing nodes at unit distance, accepted
under exclusion; deaths are
σ
jumps dissolving a node with probability
t P
dissolve
(K)
. A
nucleating triangle is the smallest rigid object and forms in a few
τ
0
; the core coordination
then climbs and
holds
(Figure 4), the derived stability holding the core where an imposed
death rate would erode it toward the foam.
Explicit mapping of the jump operators, and its status.
Strictly, Eq. (23) with
independent single-bond jumps does not by itself generate the composite events of the
growth rule: a stitch creates two bonds simultaneously, a lift three, each together with
a new node, its position, and a metric-exclusion test. The mapping below therefore
posits many-body birth jumps whose rates are xed by detailed balance on the bonds
they form, not derived from a microscopic systembath coupling; the assembly algorithm
is a geometry-conditioned Markov process consistent with this trajectory picture, not a
literal unraveling of the single-bond master equation. The generator whose trajectories
do
reproduce the rule can be written explicitly:
˙ρ =
i
[H, ρ] +
X
x∈S(C)
γ
s
(x) D[J
s
(x)]ρ +
X
x∈L(C)
γ
(x) D[J
(x)]ρ +
X
b
γ
D[σ
b
]ρ,
(29)
with composite birth jumps
J
s
(x) = P
adm
(x) a
x
σ
+
xi
σ
+
xj
, J
(x) = P
adm
(x) a
x
σ
+
xi
σ
+
xj
σ
+
xk
,
(30)
Here
a
x
creates the node degree of freedom at
x
, and
P
adm
(x)
projects onto congurations
satisfying the hard-core and proximity constraints. The sets
S(C)
and
L(C)
are the
admissible stitch and lift sites of the current conguration
C
.
29
Two features take this outside the ordinary Lindblad setting:
a
x
changes the particle
number, and the admissible jump set depends on
C
. Equation (29) is therefore a
hybrid
Fock-space quantum Markov process
. The state space is
H =
L
N=0
H
N
over
N
-node
embedded congurations, with
a
x
: H
N
H
N+1
, and
P
adm
encodes classical geometric
conditions on the embedding.
Equation (29) is the model's dynamical denition. It states how nodes are created, why
a stitch needs two anchors and a lift three, and where geometric admissibility enters.
What remains open is deriving the composite rates
γ
s
, γ
from a microscopic systembath
coupling; below they are xed by detailed balance on the bonds each jump creates.
The mapping requires a precise statement, because the Lindblad jumps act on
bond
states
while the moves are
node
placements.
How a node is born.
A
σ
+
b
jump sets a bond
b
from
|0
to
|1
. In the unraveling, a
node is
born
when a coincident set of such jumps simultaneously raises the bonds that tie
a new site to the existing network: two for a stitch (the apex of an equilateral triangle
on an edge) or three for a lift (the apex of a regular tetrahedron on a face). Concretely,
the birth of a node
x
is the joint jump
Q
i∈A(x)
σ
+
(x,i)
over the anchor set
A(x)
(
|A| = 2
stitch,
3
lift), accepted with Metropolis probability
min(1, e
βE
) = min(1, e
+βε|A(x)|
) = 1
(bond-forming births are downhill and always accepted; the thermal factor acts on the
reverse, dissolution channel through detailed balance); a
σ
b
jump lowers a bond, and
a node dissolves when its surviving bonds fall below rigidity, reproducing
P
dissolve
(K)
of
Eq. (28).
The continuous bond-ip rates
γ
, γ
thus generate the discrete moves through the
ad-
missible anchor sets
: the geometry enters by restricting which coincident
σ
+
patterns
correspond to a unit-distance registered site.
The conguration space, made precise.
To state the positional conditioning exactly
instead of informally, dene the conguration space
C =
n
(V, E, x) : |x
i
x
j
| R
ex
i = j, E
ij : |x
i
x
j
| R
b
o
,
(31)
the set of node embeddings
x : V R
3
obeying hard-core exclusion at
R
ex
together with
the bonds admissible within the proximity radius
R
b
. The Lindblad jump operators act
as maps between elements of
C
: a birth
Q
i∈A
σ
+
(x,i)
sends
(V, E, x) (V
, E
, x
)
with
V
= V {x}
for an apex
x
at unit distance from its anchor set
A
, admitted only if
x
satises the exclusion constraint in Eq. (31); a dissolution
σ
performs the reverse.
The dynamics is thus a Markov process on
C
, and the metric is explicit in the constraints
|x
i
x
j
| R
ex
and
R
b
that dene
C
. This makes precise the sense in which the model is
positional. The master equation evolves a state
on
C
, and
C
is built from a presupposed
metric. It does not construct
C
from metric-free data. A pre-positional theory would
derive
C
, the very notion of unit distance and exclusion, from the entanglement structure
itself; that derivation is the open problem of Section 26, and stating
C
explicitly here is
what makes the boundary between what the model does and does not do exact.
The limitation is explicit. Equation (23) is
not
yet a fully pre-positional theory in which
the Lindblad operators spontaneously generate geometry: it is a bond-state dynamics
con-
ditioned on the admissible geometric move set
. The jump operators do not by themselves
30
Algorithm 1
Quantum-trajectory assembly (a trajectory representation of Eq. (23); see
text for its status)
1:
seed a Bell pair / triangle nucleus (edge
L
)
2:
for
each step
t
(units of
τ
0
)
do
3:
births (
σ
+
):
stitch (in-plane apex) or lift (apex at
p
2/3 L
); reject on exclusion
R
ex
(R
, L)
; bond within
R
b
4:
deaths (
σ
):
dissolve each node with prob
t P
dissolve
(K)
5:
record core
K
6:
end for
0 10 20 30 40 50 60
time
t / τ
0
(
τ
0
=
/ε
4
t
Planck
)
4
6
8
10
12
core coordination
K
®
core
K
= 12
reached
foam
K
®
5
.
4
triangle
nucleates
Nucleation to
K
= 12
in physical time
derived stability
q
= 1
/
(1+
e
)
Figure 4: Dissipative limit: the core coordination climbs to
9
9.5
with
K=12
reached
and holds, far above the rigidity-only glass (
K 5.4
); one step is
τ
0
=
.
single out the stitch and lift placements; the set of unit-distance registered apices, supplied
by the presupposed metric and exclusion, does. Within that conditioning the mapping is
exact, each move is a specic coincident-jump pattern with the detailed-balance weight,
but the conditioning itself is the positional input agged as the deepest open problem
(Section 26).
15
K=12
is a forced terminus
The geometric bound.
The simulation reaches
K=12
; we show it cannot do otherwise.
The twelve nearest-neighbor directions form the cuboctahedral shell, mutually
L
apart
with nearest pairs at exactly
L
. A thirteenth node at unit distance from the center
must sit on the unit sphere outside the exclusion radius of all twelve; the best it can do
is the center of the largest vacancy, which is a
square face
of the cuboctahedron with
center-to-vertex chord
R
=
q
2
2 L 0.76537 L,
(32)
a closed-form constant conrmed by a global maximin search (Figure 5). Therefore
R
< R
ex
< L =
no thirteenth neighbor, all twelve admitted, (33)
and inside this window the kissing-number theorem [18] makes
K=12
a geometric terminus
for any growth history.
31
R
= (2
p
2
)
1
/
2
L
12-shell: largest hole is a square face
(no 13th neighbour fits for
R
ex
> R
)
Figure 5: The cuboctahedral shell (blue); its largest vacancy is a square face (red). A
thirteenth node at unit distance approaches no closer than
R
=
p
2
2 L
to an occu-
pied site, so any
R
ex
> R
forbids it
K=12
is forced.
Two distinct thresholds.
The upper edge
R
ex
= L
is the lattice-freezing transition,
observed directly in the simulation. The lower edge
R
is the
absolute geometric
threshold
below which a thirteenth-neighbor site exists. It is not the same as the
observed
lower
wall of the exclusion-radius sweep, which sits at the triangle circumradius
L/
3 0.577 L
(Ref. [22]).
The gap between the two is kinetic protection by the operator basis. The thirteenth-
neighbor site is the square-face vacancy, and it lies at unit distance from exactly one
existing node: the shell center. A stitch requires two unit-distance anchors and a lift
requires three. Neither operator can therefore ever propose it. So for
R
ex
(L/
3, R
)
the site is geometrically admissible but kinematically unreachable, and for
R
ex
> R
it is
excluded outright.
K=12
is thus geometrically forced inside the window (33) and kinetically protected below
it. It is not a value the kinematics must be tuned to reach.
16 The selection of FCC over HCP
FCC and HCP are stacking isomers, both close packings at
K=12
, and the selection is
invisible to local and code-theoretic measures. The local stabilizer groups are isomorphic,
the code rate (
4.02
/atom) and distance (
3
) coincide, and, we veried, the bulk-interior
diagnostic gives modal
K=12
for HCP as well, so the saturation data cannot distinguish
ABC from ABAB.
Contact counting cannot decide it either.
No renement of the bond count settles
the question. Maximizing unit-distance contacts selects Barlow close packing, of which
FCC and HCP are the two stacking isomers, and small maximal-contact clusters are
32
common fragments of both. A cluster of a dozen nodes cannot exhibit an FCC bulk node
at all, since that requires twelve neighbors together with populated second and third shells.
Any argument that terminates in maximal contacts therefore delivers close packing and
stops one step short of FCC. The selection has to come from somewhere else.
The stacking is selected by the growth operator, not by the energy.
Label the
lateral registry of the
n
th close-packed sheet by
s
n
Z
3
= {0, 1, 2}
, the conventional
A
,
B
,
C
positions. Close-packed attachment of the next sheet requires
s
n+1
s
n
χ
n
(mod 3), χ
n
{+1, 1},
(34)
since the new sheet must sit in one of the two hollow registries of the one below. The
two stacking isomers are then distinguished by a single discrete property of the sequence
χ
n
: FCC is
χ
n
constant, giving
ABCABC . . .
for
χ = +1
and its mirror
ACBACB . . .
for
χ = 1
, while HCP is
χ
n
alternating,
+1, 1, +1, 1, . . .
, giving
ABAB . . .
.
The lift of Section 2.1 places an apex above an oriented triangular face at the tetrahedral
height. The outward normal xes which
side
of the sheet grows. It does not x the sign
in Eq. (34): both continuations are geometrically admissible at unit bond length, and a
cyclic ordering of the face does not by itself select between the two nontrivial rotations
of
Z
3
. Selection therefore requires one additional bit, carried by the advancing frontier
rather than by the local geometry, a stacking chirality that the lift transports unchanged
from parent face to daughter face.
The consequence, if the frontier transports that bit.
Suppose the lift acts on an
oriented frontier state
(f, χ)
and returns a daughter frontier carrying the same
χ
. Then
χ
n
= χ
for every defect-free lift, and Eq. (34) integrates to
s
n
= s
0
+ (mod 3),
(35)
which is
ABCABC . . .
or
ACBACB . . .
: the two mirror orientations of FCC. HCP is
excluded, because an alternating increment would require the frontier to reverse its trans-
ported orientation at every single layer.
Limits of the argument.
It is a minimal-suciency statement, not a derivation of FCC
from geometry alone. Registry-increment conservation is built into the transport rule, so
the induction is not where the content lies. The content is the identication of exactly
what must be transported:
one
conserved binary frontier variable is enough to exclude
HCP; an oriented normal alone is not enough; and no stacking-dependent energy term is
required.
Whether the microscopic dynamics of Section 14 conserves that variable, and treats its
reversal as a stacking fault, is an implementation condition we have not veried. It is
at least consistent with what the simulation produces: the simulated clusters of Ref. [22]
are polycrystalline, with the shortfall from
K=12
concentrated at
K=10, 11
(Ref. [22]),
which is what a population of stacking faults and misoriented domains looks like.
Why the cell structure matters.
The two stackings also dier in their interstitial
geometry, and the dierence is exactly the one the atness of the close packing depends
on. In the regular tetrahedraloctahedral honeycomb of the FCC branch, two tetrahedra
and two octahedra meet at every edge. Their dihedral angles are supplementary,
θ
T
= arccos
1
3
, θ
O
= arccos
1
3
= π θ
T
,
(36)
33
so that
2θ
T
+ 2θ
O
= 2π
identically and every spatial Regge edge decit vanishes. This is
the exact statement behind the disappearance of the two-sheet frustration in Eq. (20): the
transient foam is all-tetrahedral and carries the irreducible decit
δ = 2π 5 arccos
1
3
7.36
of Eq. (1), because a pure tetrahedral fan around an edge cannot close. Octahedral
cells appear only when the third sheet completes the cuboctahedral shell, and it is their
supplementary dihedral angle that closes the fan exactly. The octahedral voids are also
where the code term could distinguish the two stackings, for the reason given in Section 9;
we have not computed that split.
Two static selectors.
Independently of the growth argument, two structural properties
distinguish the two lattices. (i) Bravais structure: FCC is a Bravais lattice (
Z
3
), HCP is
not. (ii) Rank-four isotropy: the HCP fourth-moment bond tensor carries a
c
-axis term
T
zzzz
= 2.667 = T
xxxx
= 2
, forbidden for an isotropic continuum, while FCC has only
cubic anisotropy.
The vibrational tiebreaker.
A third selector is vibrational entropy: the central-force
phonon entropy is marginally higher for FCC (we conrm the sign of the established
hard-sphere result of Bolhuis and Frenkel; the magnitude is small, of order
10
3
k
B
per
node, and convention-dependent, so we treat it as a consistent tiebreaker instead of the
decisive selector, with the computation in the accompanying scripts).
Cuboctahedron over icosahedron.
The codeable cuboctahedral order is in turn chosen
over the icosahedral glass that also realizes
K=12
. The relevant competition is between
two constraints. Monogamy, the property that makes a bounded coordination number
meaningful in the rst place (Section 2.1), marginally favors icosahedral packing, by
the Thomson comparison
49.165 < 49.342
. Codeability runs the other way. The code
term closes only with the cuboctahedron's square faces, which the icosahedron lacks.
Codeability overrides the sub-percent monogamy preference.
17 The lift rate factorizes
Because Eq. (33) makes the terminus history-independent, the lift rate cannot aect it.
An accretion simulation with hard-core exclusion, in which the stitch/lift choice sets only
the order of node addition, gives the same terminal coordination across
P
lift
[0.005, 0.5]
,
two orders of magnitude, no trend (Figure 6); varying
R
ex
reproduces the window. (The
terminal bulk
modal
value in these short unannealed runs is
10
11
, the grain-boundary
value of a polycrystal, matching the bulk mean
11.40
of Ref. [22] with the shortfall concen-
trated at
K=10, 11
; it reects quench rate, not the forcing.) Nor is there a parameter-free
lift rate: a birth captures a node into a registered apex, and the capture-volume ratio of
a lift (zero-parameter point target) to a stitch (one-parameter line target) carries exactly
one extra power of the bond-shell width
w
,
P
lift
P
stitch
C w, C = O(1),
(37)
veried numerically (the ratio falls monotonically
0.137 0.027
as
w : 0.15 0.03
, no
plateau). This geometric acceptance xes the form, never the value.
The full lift rate, however, factorizes into this geometric acceptance and a
thermal
survival
factor. In transition-state form, write the composite rates as
γ
s
= Γ
s
s
(w) e
βF
s
and
34
γ
= Γ
(w) e
βF
, with
Γ
the attempt frequencies,
Ω(w)
the geometric phase-space
(solution-manifold) factors at tolerance
w
, and
F
the activation free energies; then
γ
γ
s
=
Γ
Γ
s
(w)
s
(w)
e
β(∆F
F
s
)
.
(38)
This section's factorization corresponds to two identications. The rst is
/
s
w
: a
0D point set measured against a 1D circle, at tolerance
w
. The second is
F
F
s
= 3ε
,
the cost of the three exposed anchoring bonds. Together they give
γ
s
= C w e
3βε
,
which equals
C w e
3
at the operating point
βε = 1
.
The activation energy is a kinetic model, not a derivation.
The apex bonds at
the transition state are formed and energetically favorable. What distinguishes them is
their lack of in-plane redundancy: each is the node's only support in its direction, with no
closed triangle behind it. We take this to price the lift intermediate at
3ε
above the stitch
intermediate. In energy-landscape form,
E
stitch
= E
0
+
s
and
E
lift
= E
0
+
s
+ 3ε
. The
outstanding step is to obtain that extra
3ε
explicitly, from unsatised stabilizer terms,
missing closed loops, or transient bond strain. The present Hamiltonian rewards formed
bonds by
ε
and does not itself penalize them for being exposed.
A bookkeeping point.
The simulation parameter
P
lift
= e
3
0.05
is the
full
per-
proposal lift probability. Equating it to the thermal factor alone therefore amounts to
the normalization choice
Cw = 1
at the operating tolerance, which we adopt as a stated
convention.
The factorization nonetheless separates four ingredients: attempt-frequency ratio, phase-
space suppression, activation energy, and temperature. It also makes the claim testable.
The prefactor should scale linearly in a
w
sweep, and the exponent should steepen as
e
3βε
in a temperature sweep. A lift places an apex with three out-of-plane anchoring bonds
that are exposed, unstabilized by any in-plane neighbor, until the cooperative three-apex
seed of the next sheet closes around them; a stitch, lying in the plane, exposes none. At
the detailed-balance temperature
kT
0
= ε
that xes
q = 1/(1 + e)
(Section 13), each
exposed bond carries a Boltzmann factor
e
ε/kT
0
= e
1
, so the thermal ratio of lift to
stitch is
P
lift
P
stitch
thermal
= e
3
,
(39)
independent
of the tolerance
w
, with the exponent
3
set by the three exposed anchoring
bonds. The net rate is the product of the two factors: a tolerance-dependent geometric
acceptance
w
(Eq. (37), not derivable) times the thermal factor
e
3
(Eq. (39), xed by
the same
T
0
= ε
that gives
q
, conditional on one binding quantum per exposed bond). The
simulation's
e
3
therefore sits at the thermal factor. It is not a free constant: it follows
from the model's detailed-balance temperature. The model does not, however, predict
the absolute lift probability, which is this thermal factor times the tolerance-dependent
geometric prefactor. The lift rate is free in its geometric acceptance and xed in its
thermal factor; the two statements refer to the two factors and do not conict.
35
10
2
10
1
lift rate
P
lift
(free parameter)
8
9
10
11
12
terminal bulk modal
K
K
= 12
ceiling (kissing bound)
Terminus independent of lift rate over 2 decades
Figure 6: Terminal bulk coordination is independent of the lift rate across two orders of
magnitude of
P
lift
; the
K=12
ceiling is the kissing bound. The lift rate sets only the order
of node addition, not the terminus.
18 The parameter the model must supply: a rigidity
scale
If the lift rate factorizes and
K=12
is forced, what must the model x for the lattice to
exist? Here the one energy scale of the bond-state Hamiltonian is not sucient. The
positional realization of the bond requires a curvature scale
κ
in addition to the binding
depth
ε
, derived self-consistently from the phonon spectrum. Each bond is a central well
of curvature
κ
(units
ε/L
2
); the FCC dynamical matrix is
D(q) =
κ
m
12
X
j=1
1 cos(q·n
j
)
ˆn
j
ˆn
j
,
(40)
and the mean-square displacement, including zero-point and thermal motion, is
u
2
=
κm
D
1
2˜ω
coth
˜ω
2t
E
, t
kT
p
κ/m
,
(41)
averaged over the Brillouin zone.
The displacement convention.
We pin the constants by a converged Brillouin-zone
integration under the
relative-displacement
(Lindemann) convention,
p
⟨|u
i
u
j
|
2
<
L R
for nearest neighbors
ij
. This is the physically relevant choice, because it retains
the phonon correlations
u
i
· u
j
that independent-node conventions discard. Monkhorst
grids from
16
3
to
32
3
agree to four digits, and the shifted grid excludes the acoustic
zero mode. Independent-node conventions give
10.5
31.5
and
0.022
0.066
for the two
constants below, bracketing the pinned values. The qualitative conclusion is convention-
independent: a single-scale vacuum sits at its melting point.
Two rigidity conditions.
The forced lattice is rigid only if bond uctuations do not carry a neighbor across the
wall
R
:
L
p
2u
2
> R
, i.e.
2u
2
< (1 R
/L)
2
= 0.0551 L
2
. Two derived conditions
follow (Figure 7). A zero-point oor,
κm L
2
> 28.6,
(42)
36
10
2
10
1
10
0
10
1
reduced temperature
t
=
kT/
(
=
p
/m
)
0.6
0.7
0.8
0.9
1.0
nearest-neighbour separation
/L
t
c
Rigidity of the forced
K
= 12
lattice (two-scale)
min bond length
L
q
2
u
2
®
R
= (2
p
2
)
1
/
2
(K=12 wall)
Figure 7: Nearest-neighbor separation versus reduced temperature
t = kT/
(
=
p
κ/m
), from the FCC phonon spectrum. The lattice is rigid (green) while the uctuating
separation stays above the
K=12
wall
R
(red), and melts past
t
c
; rigidity xes the bound
Eq. (43).
so even at
T = 0
the lattice must be sti and heavy enough that quantum motion stays
inside the window; and a thermal separation,
kT
κL
2
< 0.031 κL
2
32 kT.
(43)
We round this bound up and quote
κL
2
36 ε
throughout, a slightly stronger requirement
than the integration strictly demands.
A single-scale vacuum, with
kT ε κL
2
, gives a ratio of order unity. That is an
order of magnitude above the bound. Such a vacuum sits at its melting point and cannot
crystallize. This also relieves the only tension in Section 13:
q = 1/(1 + e)
uses
T
0
= ε/k
B
with
ε
the binding
depth
, while rigidity constrains
kT/(κL
2
)
with
κL
2
the
curvature
; the
two coexist provided the bond well is deep-and-narrow,
κL
2
36 ε
. The
K=12
vacuum
exists precisely when the binding well is sti in that sense.
19 The construction velocity
The in-plane speed.
The dynamics xes the speed of the assembly. The front advances
by attachments net of detachments; with attempt frequency
1
0
and detailed balance,
the net forward rate per site is the same
q
that sets stability,
(γ
γ
) = (12q)
0
= (e
1)/(e + 1)
0
0.462
0
, with the normalization
γ
+ γ
1
0
dening the microscopic
attempt time (detailed balance xes only the ratio of the rates; their sum is a convention
absorbed into
τ
0
). The in-plane (stitch) growth is fast and the move is abundant, a stitch
needs only two equidistant anchors where a lift needs three, so a
K=6
sheet grows radially
at the speed
v
2D
= (1 2q)
3
2
v
lat
0.40 v
lat
0.07 v
sig
.
(44)
37
The construction is anisotropic.
The out-of-plane lift is rarer (one fewer solution
dimension, and the binding term favors the at
K=6
contact maximum over the buckled
foam), and its rate is the amplitude
P
lift
discussed in Section 17. The construction is
therefore
anisotropic
: fast in-plane at Eq. (44), and lift-limited in the stacking direction.
The naive estimate of a single dimension-independent build speed is incorrect, precisely
because it would equate the stitch and lift rates, which the geometry forbids. The phys-
ically meaningful parameter-free number is the in-plane speed
v
2D
; the stacking advance
inherits the lift-rate freedom.
The anisotropy is the same
e
3
that suppresses the lift.
Per frontier site, a lift is
attempted and accepted at
P
lift
times the stitch rate, and it advances the structure by the
interlayer spacing
p
2/3 L
rather than the in-plane step
3
2
L
. The two speeds therefore
stand in the ratio
v
2D
v
stack
=
1
P
lift
3/2
p
2/3
= e
3
× 1.06 21,
(45)
with the bare rate ratio
1/P
lift
= e
3
20
and the geometric step-length correction supply-
ing the remaining
6%
. Lateral growth thus outruns stacking by a factor of roughly twenty,
and that factor is not independent of the lift suppression: it
is
e
3
, the same exponential
that makes the lift rare. Numerically,
v
stack
0.019 v
lat
against
v
2D
0.40 v
lat
.
The ratio recurs on every new layer.
A lift does more than advance the stack by
one node. It seeds an entire new sheet, and that sheet then spreads at the same
v
2D
. The
anisotropy is therefore not a one-time property of a single frontier site but applies afresh
to each layer as it is born. In the time one layer of thickness
p
2/3 L
is added, the sheet
carrying it widens by roughly
21 × 0.82 L 17 L
. Growth is self-similar. Every sheet, at
every stage, outruns the stack it sits on by the same factor
e
3
.
Why the cluster is nonetheless compact.
This does
not
make the crystallite a
pancake of aspect
1/21
. If the structure grew as a single stacking column, the recurring
21:1
anisotropy would give a cluster aspect ratio
z/xy 0.047
; the sweep of Table 2 of
Ref. [22] measures
0.83
at
P
lift
= e
3
, larger by a factor of
18
. The discrepancy is the
branching channel. Sheets nucleate in parallel across the cluster instead of sequentially
up one column, so many layers advance at once.
The gap closes monotonically as lifts become common, the measured-to-single-column
ratio falls
63, 27, 18, 8.9, 6.4, 3.3, 2.0, 1.2
across
P
lift
= 0.01
to
0.85
, and reaches unity
only when lifts are so frequent that no branching advantage remains. That the two agree
at
P
lift
1
and diverge as
P
lift
0
is a quantitative check on the branching picture of
Section 20. Taken with the signal front
v
sig
= 4
2 v
lat
(Section 12), the construction front
runs at
v
2D
0.07 v
sig
: local assembly proceeds at roughly one-fourteenth of the fastest
speed the lattice can carry.
What is xed here is a ratio, not a speed.
Every velocity in this section is quoted
in units of
v
lat
= Lε/
, and the model does not x
L
or
ε
separately (assumption A2,
Section 8). The absolute construction speed is therefore unknown. What the dynamics
xes are the dimensionless ratios:
v
2D
/v
lat
= 0.40
,
v
2D
/v
sig
1/14
, and the lateral-to-
stacking anisotropy
21
of Eq. (45). These are parameter-free because
L
and
ε
cancel
in each.
Converting
1/14
into a statement about the physical speed of light requires the further
identication
v
sig
= c
. That identication is conditional, not established here. It rests
38
on the GW
=
light constraint of Eq. (26), which xes only the elastic
trace
speed, and the
no-go theorem of Section 23 shows that no stable elastic medium carries all polarizations
at a single speed. Until a sector is identied that does,
v
sig
is the lattice's own causal
bound, and
0.07 c
should be read as
0.07 v
sig
.
20 Exponential branching growth: an ination-shaped
geometric conversion
Sheets seed sheets.
A lift does more than advance the stacking front by one node. It
seeds an entire new plane, which then grows laterally at the fast in-plane speed
v
2D
. Each
growing sheet is itself a substrate for further lifts, so sheets seed sheets, a self-exciting
(branching) process. Writing the population in moments (sheet number
N
, total radius
R
, total area
A
, with seeding rate
σA
,
σ P
lift
), the chain closes as
...
A = 2πv
2
2D
σ A = V (t) e
Γt
, Γ
2πv
2
2D
σ
1/3
P
1/3
lift
,
(46)
an
exponential
growth of the crystallized volume (Figure 8), conrmed numerically over
many orders of magnitude in
V
. The cluster aspect ratios of Table 2 of Ref. [22] test this
independently: they exceed the single-column prediction of Section 19 by a factor that
falls from
63
to
1.2
as
P
lift
rises from
0.01
to
0.85
, which is the signature of parallel sheet
nucleation. The rate inherits the lift-rate freedom (as a cube root, the seedingradius
area chain being three steps), so it is not a xed number; the number of
e
-folds is set by
the foam reservoir,
ln(V
foam
/V
seed
)
, because new sheets nucleate only into the metastable
foam and growth halts exactly when the foam is consumed, a built-in graceful exit.
Why this is labeled speculative.
This exponential, self-terminating conversion of
metastable foam into crystal is a geometric analog of ination-with-reheating, accelerated
growth driven by a metastable phase, ending cleanly on reservoir depletion. It is an
analog
: it concerns the build-up of lattice volume, not the cosmological scale factor.
It is labeled speculative for two reasons. First, the spatial branching is scale-free. The
clustering spectrum follows a power law with
R
2
= 0.96
over the inertial range. That
is the prerequisite for an inationary spectrum, but not the spectrum itself. The raw
nucleation-clustering slope is steeply red (
n 3.3
), and we have not computed the
frozen, horizon-crossing curvature spectrum that would be compared to the observed
n
s
0.965
[19]. Second, identifying exponential growth of
lattice volume
with metric
ination requires the equation of physical space with the lattice, which remains unproven
(Section 26). The mechanism is genuine and ination-shaped; the claim that it
is
ination
is not established.
21 End-to-end coherence and robustness
One rule, end to end.
The preceding mechanisms were derived piecewise. We now test
whether they cohere under a
single
xed rule. We run one Metropolis-kinetic dynamics,
propose stitch and lift wherever geometrically available, accept a birth with Metropolis
probability
min(1, e
βE
) = 1
for
E = ε n < 0
(
n
the bonds it forms; births are
39
0 50 100 150 200
time
/τ
0
10
0
10
2
10
4
10
6
10
8
crystallized volume
V
(
t
)
Branching growth: exponential, self-terminating
lift amp
p
= 0
.
0050
lift amp
p
= 0
.
0005
foam reservoir (exit)
Figure 8: The branching phase: crystallized volume grows exponentially (note the log-
arithmic axis) and saturates exactly at the foam reservoir, an ination-shaped, self-
terminating conversion. The rate scales as
P
1/3
lift
and so inherits the lift-rate freedom.
always accepted, the thermal factor entering through dissolution), and dissolve each node
with probability
t P
dissolve
(K)
from the derived stability, starting from a bare Bell pair,
with no per-stage switches. The same rule nucleates a triangle, grows sheets, lifts, and
forms a
K=12
bulk: under the bulk-interior diagnostic the interior reaches modal
K=12
early and holds it, with the bulk node count rising monotonically. The pieces cohere; they
do not ght at the seams.
Robustness across temperature.
Robustness is conrmed by sweeping the bath tem-
perature over a factor of eight (
β = k
B
T
from
0.4
to
3.0
, i.e.
q
from
0.40
to
0.047
) at
four seeds each:
every
run reaches bulk modal
K=12
, with only one of four landing on a
grain-boundary
K=11
at the coldest point (Figure 9).
K=12
is the generic outcome of
the dynamics, not a ne-tuned one, and the derived operating point
q = 1/(1 +e)
(
β = 1
)
sits in the middle of the working range, not at its edge. The all-node mean coordination
plateaus near
9
(a nite, polycrystalline crystallite with modal
K=12
interior, match-
ing the bulk mean
11.40
of Ref. [22]); reaching single-crystal
K 12
is an annealing
question, not a missing parameter.
22 Derived scale relations
Several quantitative relations follow directly from the results above; we collect them here.
Each is labeled by what it rests on.
Node inertia bound (D).
The zero-point oor of Section 18,
κm L
2
/ > 28.6
,
rearranges to a lower bound on the node inertia,
m > 28.6
2
2
/(κL
4
)
. Using the rigidity
requirement
κL
2
36 ε
and
v
lat
= Lε/
gives
m 22.7 ε/v
2
lat
; with the light cone
c = 4
2 v
lat
,
m c
2
7.3 × 10
2
ε.
(47)
40
Figure 9: Robustness of the assembly: under one end-to-end rule, the bulk interior reaches
K=12
for every seed across a factor-of-eight temperature range (green), with
K
(blue)
plateauing at the polycrystalline crystallite value. The derived point
q = 1/(1 + e)
lies
mid-range, not at a cli.
A stable close-packed node must carry an eective inertia of order seven hundred times
the binding scale, a derived massenergy hierarchy, conditional on the
c = 4
2 v
lat
light
cone and the pinned Lindemann convention of Section 18.
Critical rigidity temperature (D).
The melting condition
kT/(κL
2
) < 0.031
of Sec-
tion 18 sets a critical temperature
T
c
0.031 κL
2
/k
B
. Imposing the derived stiness
κL
2
36 ε
,
T
c
0.031 × 36
ε
k
B
ε
k
B
= T
0
.
(48)
The melting threshold sits right at the bath scale
T
0
= ε/k
B
that drives assembly. This
explains why the model requires the factor
36
: it makes the close-packed phase just
rigid enough to survive the same thermal scale at which it is built.
A geometric small parameter (T).
The Regge decit supplies a genuine small di-
mensionless number,
ε
geom
δ
2π
=
2π 5 arccos
1
3
2π
2.0 × 10
2
,
(49)
geometric rather than tuned. It controls the residual anisotropy at
O(ε
2
geom
)
and the foam
instability strength at
O(ε
geom
)
.
Branching rate and exit time (S).
With the construction estimate
v
2D
0.40 v
lat
of Section 19, the branching rate of Section 20,
Γ (2πv
2
2D
σ)
1/3
with seeding density
σ = α
σ
P
lift
/(L
2
τ
0
)
, reduces to
Γτ
0
2π(0.40)
2
α
σ
P
lift
1/3
α
σ
P
lift
1/3
,
(50)
the
O(1)
prefactor collapsing to near unity, so the exponential rate is essentially the cube
root of the eective lift-seeding rate (and inherits its freedom). The exponential phase
41
then has a denite exit time,
t
exit
= Γ
1
ln
V
foam
V
seed
,
(51)
separating
how much
expansion (the reservoir ratio, the
e
-fold count) from
how long
it
lasts (the seeding rate). Growth halts when
V
crystal
= V
foam
and
Γ 0
, a graceful exit
requiring no added decay mechanism.
A polycrystallinity order parameter (C).
The all-node mean coordination plateaus
near
K 9
while the bulk interior is modal
K=12
, suggesting the order parameter
f
defect
1
K
12
0.25,
(52)
a measure of polycrystallinity (under-coordinated surface and grain-boundary nodes),
not a literal defective fraction. We note that this plateau is a grain-structure (nucleation)
eect: direct tests show post-growth relaxation does not drive
K
toward
12
, so reaching
single-crystal coordination is a nucleation/annealing question and not achieved by local
relaxation alone.
23 Further consequences. The acoustic spectrum and
the vacuum energy
Two quantities follow directly from the geometry and the GW-xed stiness
κ =
16
2
/
2
of Section 12. Both sharpen, instead of soften, the constraints the model
must meet, and we state them as such.
The acoustic spectrum and its anisotropy (T).
The FCC phonon spectrum of
Section 18 (the dynamical matrix (40)) is a nearest-neighbor central-force model; in the
long-wavelength limit it is governed by the
rank-four
bond tensor [11],
D
αβ
(q)
κL
2
2m
q
µ
q
ν
T
µναβ
, T
µναβ
=
12
X
j=1
ˆn
µ
j
ˆn
ν
j
ˆn
α
j
ˆn
β
j
= δ
µν
δ
αβ
+δ
µα
δ
νβ
+δ
µβ
δ
να
µναβ
,
(53)
with
µναβ
= 1
only when all four indices coincide. Unlike the rank-two
S
µν
= 4δ
µν
that
governs the scalar channel,
T
carries the cubic term
, so the three acoustic branches are
isotropic only in their trace. Diagonalizing along the symmetry directions gives, in units
of
L
p
κ/m
,
ˆ
q
longitudinal transverse transverse
[100] 1 1/
2 1/
2
[110]
5/2 1/
2 1/2
[111]
p
4/3 1/
3 1/
3
42
The longitudinal speed runs from
L
p
κ/m
along
[100]
to
p
4/3 L
p
κ/m
along
[111]
,
a parameter-free anisotropy of
p
4/3 1 15.5%
set entirely by the FCC bond ge-
ometry. With
κ
xed by GW
=
light (Eq. (26)) these become
v
L
[0.71, 0.82] c
and
v
T
[0.35, 0.50] c
. The three branch speeds obey the trace identity
v
2
L
+ v
2
T
1
+ v
2
T
2
= c
2
in every direction, which is the content of Eq. (26). The bare lattice therefore carries
sub-luminal, anisotropic
sound. The isotropic scalar speed
c
s
= L
p
2κ/m = c
of Sec-
tion 12 survives only in the trace channel. This is the concrete form of the residual cubic
anisotropy anticipated there. A nearest-neighbor central-force vacuum is thus Lorentz-
violating at the lattice scale, at the
p
4/31 15.5%
level in its longitudinal branch and
the
2 1 41%
level in its transverse branches (spread
[
1
2
,
1
2
] L
p
κ/m
across direc-
tions), the transverse sector being the one relevant to tensor (gravitational-wave) modes;
full continuum isotropy, with a single
c
shared by all polarizations, requires either angular
(bond-bending) couplings beyond nearest-neighbor central forces or a renormalization-
group ow to an isotropic xed point. We record the bare anisotropy as a sharp quanti-
tative target, not a solved problem.
Polycrystalline isotropization (D).
The
directional
anisotropy above (
15.5%
lon-
gitudinal,
41%
transverse) is a single-crystal property, and the bond tensor obeys the
Cauchy relation
C
12
= C
44
(Zener ratio
A = 2C
44
/(C
11
C
12
) = 2
) characteristic of
a central-force lattice. The vacuum described here, however, is a polycrystal of ran-
domly oriented grains. Averaging the cubic tensor over orientations removes the direc-
tional dependence entirely. We use the standard VoigtReussHill construction, in which
Voigt and Reuss give the uniform-strain and uniform-stress bounds and Hill takes their
mean. The result is an isotropic eective medium with
v
L
1.08 L
p
κ/m 0.76 c
and
v
T
0.62 L
p
κ/m 0.44 c
at the Hill average.
Two consequences.
Above the grain size, the misoriented-crystallite scale that produces
the coordination scatter
σ
K
0.99
reported in Ref. [22], the vacuum has no preferred di-
rection, so any directional gravitational-wave birefringence is conned to sub-grain scales,
a falsiable prediction. But isotropization does not merge the polarizations. The longi-
tudinal and transverse speeds remain split,
v
L
/v
T
1.76
. The polycrystal thus removes
the
directional
Lorentz violation while leaving the
polarization
splitting, which a single
shared cone must still close. The next paragraph shows what that closing can and cannot
look like.
No-go theorem for an elastic universal cone (D).
The theorem has two halves.
First: nearest-neighbor pair forces cannot produce a stable isotropic elastic
medium.
Take the general axially symmetric nearest-neighbor force matrix
Φ = α ˆnˆn
T
+
β ( ˆnˆn
T
)
, with radial stiness
α
and tangential stiness
β
. A direct computation of the
FCC elastic constants gives
C
11
α + β
,
C
12
(α 5β)/2
, and
C
44
(α + 3β)/2
. The
isotropy condition is then
C
11
C
12
2C
44
(β α)/2
, which vanishes
only
at
β = α
. At
that point the force matrix degenerates to a scalar spring
Φ = α
and all three acoustic
branches coincide. The constants stand in the ratio
C
11
: C
12
: C
44
= 2 : 2 : 2
, so
λ = µ
and the bulk modulus is
K
B
= λ +
2
3
µ =
µ
3
< 0
. The isotropic point is mechanically
unstable.
Second. No stable elastic medium carries all polarizations at one speed.
This
43
holds independently of any force model. Equality
v
L
= v
T
requires
λ + 2µ = µ
, hence
λ = µ
, hence
K
B
< 0
for any nonzero shear rigidity.
The two conditions meet at the same forbidden point. Within nearest-neighbor pair forces,
the unique isotropic conguration
is
the unique equal-speed conguration, and stability
excludes it.
The consequences are constructive.
Restoring isotropy
with
stability requires three-
body angular terms,
H
bend
=
κ
θ
2
P
ijk
(ˆr
ij
· ˆr
ik
cos θ
0
)
2
, or couplings beyond nearest
neighbors. Solving for the ratio
κ
θ
that cancels the cubic anisotropy is a dened target
calculation. Separately, a shared single speed across polarizations cannot be carried by the
displacement eld of
any
stable medium. The photon and gravitational sectors therefore
cannot both be elastic polarizations, and a distinct gauge-like sector is required. This
sharpens the open problem. The branch-level cone is closed to the elastic sector as a
matter of theorem, and open only to new sectors. If the framework contains a relativistic
tensor excitation, it must be a gauge-like, topological, or defect-based collective degree of
freedom of the bond network, not the displacement eld itself.
The vacuum energy density (D/S).
The FCC bond density is
6
2/L
3
(six bonds
per node, node density
2/L
3
), so the binding term contributes
u
bind
= ε
6
2
L
3
8.49
ε
L
3
,
(54)
negative, as a bound crystal requires. Phonon zero-point motion adds a positive
u
zp
9
8
ω
D
(
2/L
3
)
with
ω
D
4 ε
from the xed
κ
, i.e.
u
zp
+O(1) ε/L
3
, of the same order.
The net density is therefore
|ρ
vac
| ε/L
3
. With the binding oor
ε 2.3
2
/(mL
2
)
and a Planck-scale lattice (
L
P
) this is of order the Planck density, roughly
120
orders of magnitude above the observed cosmological constant: the model reproduces the
cosmological-constant problem [23] in its standard, unsolved form. The single structural
feature it oers is that
u
bind
< 0
and
u
zp
> 0
are of the same order and opposite sign,
so a cancellation is dimensionally available, though nothing in the present construction
enforces it to the observed level.
24 The cascade as a sphere-packing variational ladder
The binding term, over pairs, is
ε
times the contact number of a unit-sphere packing;
its minima, dimension by dimension, are the cascade's rungs (Table 6, Figure 10). The
K=6
sheet is the planar contact maximum; the
K=12
packing is the spatial contact
maximum, the kissing number [18] achieved everywhere only by the densest packing (Ke-
pler/Hales [3]); the
K=4
foam pays both a lower coordination and the Regge frustration,
sitting
1.37 ε
per node
above
the sheet, a barrier and, being rigid, a kinetic trap (the
glass). Registered lifts raise coordination monotonically
K : 6 9 12
; unregistered
buckling is trapped in the foam.
44
Table 6: Energy per node along the cascade, in units of the binding scale
ε
.
rung role
K
binding total
E/N (ε)
Bell pair / triangle rigid seed (nucleus) 2
1.00 1.00
hexagonal sheet 2D contact maximum 6
3.00 3.00
tetrahedral foam 3D frustration barrier (glass) 4
2.00 1.63
close packing 3D contact maximum
+
code 12
6.00 7.00
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
assembly coordinate
7
6
5
4
3
2
1
energy per node (
ε
)
triangle
K
= 2
hex sheet
K
= 6
(2D max)
foam
K
= 4
(barrier)
close pack
K
= 12
(3D min)
+1
.
37
ε
Energy ladder (units of the binding scale
ε
)
registered path:
K
6
9
12
, downhill
unregistered: through foam barrier (glass)
Figure 10: The cascade as an energy ladder (
ε
): the
K=6
sheet (2D maximum), the
K=4
foam (barrier
1.37ε
above, the glass), the
K=12
packing (
7ε
). Registered lifts (solid)
descend monotonically; unregistered buckling (dashed) is trapped.
25 The CSS code on the close-packed lattice
The code term of Eq. (21) is the stabilizer Hamiltonian of the
[[192, 130, 3]]
CSS code [21]
introduced in Section 5: vertex-star
Z
-checks and weight-12 octahedral
X
-checks that
commute over
GF(2)
, with weight-3 logical faces giving
d = 3
and rate
130/192 0.677
.
What matters for the dynamics is that this term is nonzero only where octahedral voids
exist, on the cuboctahedral close packing, which is why it appears at the top rung of the
variational ladder (Section 24) and selects that registration (Section 9).
26 Scope and open problems
Derived here:
the emergent light cone
c = 4
2 v
lat
and, from the GW
=
light (trace-
channel) constraint, the xed stiness
κ = 16
2
/
2
; the detailed-balance
q = 1/(1 + e)
and the dissolution ladder; the forced
K=12
terminus and
R
=
p
2
2 L
; the lift rate's
freedom and the non-existence of a derivable value; the rigidity bounds Eqs. (42)(43);
the energy ladder; the code parameters; and the FCC/HCP selectors, including the iden-
tication of the single transported frontier bit that suces to exclude HCP (Section 16).
Established in Part I:
the reversibility and stationary measure of the assembly, its
45
concentration on maximal
construction
bonding under a stated entropy bound, the exact
nite-state enumeration, and the structure-tensor isotropy of a close packing.
Imported as established mathematics:
the kissing and Kepler theorems [18, 3] un-
derlying the contact maxima, and the Regge decit-angle construction [9] used for the
frustrated foam.
Open:
1. Constructing the embedded model
M
emb
of Section 3.9 explicitly: a rule identifying
geometrically congruent histories, contact updates after each move, reverse moves
that remove contacts consistently, and then irreducibility of the resulting transition
graph and the decit-entropy bound on it. Detailed balance transfers algebraically;
ergodicity and concentration do not, and the thermodynamic statement for the
physical energy rests on them.
2. The registration bias of the births is motivated by the code term lowering registered-
conguration energy, but it is not proven quantitatively from BornMarkov rates.
3. The rigidity factor
36
and the zero-point oor
28.6
follow from the central-force
harmonic spectrum. A fully anharmonic well would sharpen them.
4. Reaching single-crystal
K 12
, rather than the polycrystalline modal-
12
crys-
tallite, is an annealing and quench-rate question, not a missing parameter.
5. The branching phase (Section 20) is exponential and self-terminating, but its frozen
perturbation spectrum is uncomputed and its raw clustering is steeply red. Its
identication with ination is therefore unestablished.
6. The light cone is computed in the single-excitation sector, whose band is quadratic at
long wavelength, while the linear relativistic cone belongs to the harmonic (elastic)
sector. Unifying the two, and closing the branch-level single-cone gap of Section 23,
is open.
7. The construction is positional. It presupposes node positions and a metric exclu-
sion. A fully pre-positional dynamics, and with it any genuine claim about metric
expansion, remains the deepest open problem.
27 Conclusion
The Selection-Stitch vacuum has a single dynamical origin: a Lindblad master equation
whose Hamiltonian carries one energy scale and one length. Its coherent limit propa-
gates an emergent light cone of speed
v
lat
= Lε/
, reproducing the lattice isotropy, with
LiebRobinson front
c = 4
2 v
lat
; its dissipative limit assembles the structure, its rate
q = 1/(1 + e)
derived by detailed balance and its quantum-trajectory representation
reproducing the cascade.
What turns out not to be an input.
Three apparent inputs to that cascade turn
out not to be inputs at all. First,
K=12
is a forced terminus. The kissing bound forbids
a thirteenth neighbor for any exclusion
R
ex
> R
=
p
2
2 L
. Second, the lift rate
46
factorizes into a free geometric acceptance and a thermal
e
3
xed by
T
0
= ε
, so no
single value is derivable. Third, the genuine parameter is a rigidity scale. The binding
curvature must exceed the thermal scale by a derived factor
36
, with a quantum oor on
the node inertia, so that the forced lattice resists its own zero-point and thermal motion.
A single-scale vacuum melts; a two-scale vacuum crystallizes.
Clock, ruler, and the assembled whole.
Time is the Schrödinger parameter and
length is
L
; their ratio sets the lattice signal scale, identied here with the emergent
light-cone velocity in the single-excitation sector. The journey from a single triangle
to the rigid
K=12
vacuum is one coupled dynamical framework, coherent, collective,
elastic, and dissipative sectors of a single open-system Hamiltonian, in real time and
space, with
K=12
forced, the lift rate free, and the rigidity scale derived. A single
end-to-end rule carries a bare Bell pair to a bulk
K=12
crystallite generically across
temperature, so the assembly is robust instead of ne-tuned. The lift-seeded branching
of sheets then makes the foam-to-crystal conversion exponential and self-terminating, an
ination-shaped geometric conversion.
The frontier.
The assembled lattice thus carries several of the features we associate
with physical space: spatial isotropy, a causal signal cone, and a transient homogeneous
curvature carried by the two-sheet foam. What it does not carry is the substrate itself.
The construction is positional throughout, presupposing node coordinates and a metric
exclusion, so the emergence of that positional substrate, from which a rst-principles
metric would follow, remains the frontier.
Data Availability Statement
The kinematic operators, the codimension suppression, and the compound-QEC argument
are specied in Sections 2.12.4; the Markov formulation, its acceptance rule, and the enu-
meration protocol are specied in Sections 33.6. The nite-state results are exhaustive
enumerations rather than samples, so they carry no random seed and any equivalent im-
plementation reproduces them exactly. Reference Python implementations are provided
as a verication aid.
finite_ssm_verification_v3.py
enumerates the reachable stitchlift com-
plexes of Section 3.1, deduplicates states by colored incidence-graph isomorphism,
builds the full MetropolisHastings transition matrix, and veries detailed balance,
stationarity, and the decit-sector counts of Section 3.6:
https://github.com/rag
hu91302/ssmtheory/blob/main/finite_ssm_verification_v3.py
.
run_finite_verification_v3.py
driver for the above, sweeping
βε
and the
forward lift proposal weight
ρ
to produce the concentration and
ρ
-independence
results of Section 3.6:
https://github.com/raghu91302/ssmtheory/blob/main/
run_finite_verification_v3.py
.
embedded_crossover_v1.py
exhaustive enumeration of embedded congura-
tions for
n 12
, giving the construction-bond and contact-bond maxima and their
crossover in Section 3.7:
https://github.com/raghu91302/ssmtheory/blob/mai
n/embedded_crossover_v1.py
.
47
verify_ssm_integrated.py
numerical verication of the analytic constants of
both parts. For Part I it checks the bond-set isotropy
S
µν
= 4δ
µν
, the vanishing rank-
three tensor, and the bond bookkeeping. For Part II it checks the LiebRobinson
front, the acoustic branch speeds, and the scalar-dispersion anisotropy. It also checks
the elastic constants and the isotropy no-go, the Lindemann constants, the disso-
lution probabilities, the FCC/HCP shell degeneracy, and the construction-velocity
anisotropy:
https://github.com/raghu91302/ssmtheory/blob/main/verify_s
sm_integrated.py
.
The history-resolved enumeration through
N = 8
runs in about ten seconds and the
embedded enumeration through
n = 11
in under two minutes on a current laptop; the
n = 12
level requires roughly twenty minutes and several gigabytes. Scripts for the growth
simulation of Ref. [22], which this paper cites but does not repeat, are listed in that paper's
data statement. The remaining results of Part II are analytic and are reproducible directly
from the equations as stated.
Declarations
Conict of interest:
The author declares that they have no conict of interest.
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