Geometric Phase Transitions in a Discrete Vacuum: Deriving Cosmic Flatness, Inflation, and Reheating from Tensor Network Topology

Geometric Phase Transitions in a Discrete
Vacuum:
Deriving Cosmic Flatness, Inflation, and
Reheating from Tensor Network Topology
Raghu Kulkarni
Independent Researcher, Calabasas, CA
February 22, 2026
Abstract
Standard inflationary cosmology requires introducing an ad-hoc scalar inflaton
field to account for cosmic flatness, horizon uniformity, and the early universe’s
exponential expansion. In this manuscript, we present a single-parameter geomet-
ric alternative. By modeling emergent spacetime as a discrete quantum tensor
network, we establish that these cosmological phenomena emerge as rigorous ther-
modynamic consequences of the vacuum undergoing topological phase transitions.
Applying the Euler characteristic for triangulated manifolds, we mathematically
prove that the absolute minimal-energy ground state is a two-dimensional hexag-
onal sheet (K = 6). This topologically enforces strict cosmic flatness (Ω
k
= 0)
before any volumetric nucleation occurs. A recent computational analysis of the
network’s kinematic growth [16] reveals a strict geometric cutoff at a compression
limit of 1/
3 0.577L, demonstrating that a classical zero-dimensional Big Bang
singularity is mathematically impossible. The universe fundamentally originates
as a 2D boundary sheet. Subsequent out-of-plane holographic nucleation forces
a structural transition into a three-dimensional tetrahedral foam (K = 4). Be-
cause regular tetrahedra are incapable of smoothly tiling Euclidean space, they
natively generate a positive Regge deficit angle of δ 0.128 radians. We reveal that
this topological frustration manifests physically as a constant local scalar curvature
(R
local
0.128/l
2
P
), which directly drives an exact De Sitter epoch of unbounded
exponential expansion. Furthermore, mapping this 3D volumetric gap to the nat-
ural 2D gauge boundary yields a parameter-free derivation of the scalar spectral
index (n
s
0.9646) that flawlessly matches Planck 2018 observational data. Ul-
timately, as the local network density reaches saturation, the foam undergoes a
first-order topological crystallization, snapping into a stable Face-Centered Cubic
(FCC, K = 12) lattice. By constraining the unitary stitch binding energy (ϵ) to
the Grand Unified Theory (GUT) scale, we compute the exact latent heat of this
geometric crystallization (∆Q = 4ϵ per node), deriving a phenomenologically viable
Reheating Temperature (T
reheat
10
15
GeV).
raghu@idrive.com
1
Contents
1 Introduction: The Structural Evolution of Spacetime 3
2 Phase I: The Euler Proof of Cosmic Flatness and Genesis 3
2.1 The Network Hamiltonian . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2 Proving the K=6 Flatness Constraint . . . . . . . . . . . . . . . . . . . . . 3
2.3 Resolution of the Big Bang Singularity (The 1/
3 Cutoff) . . . . . . . . . 4
3 Phase II: Tetrahedral Foam and Geometric Inflation 4
3.1 Holographic Nucleation and the Regge Deficit Angle . . . . . . . . . . . . . 4
3.2 De Sitter Expansion and the Exact Derivation of n
s
. . . . . . . . . . . . . 5
4 Phase III: Saturation and Reheating 6
4.1 The K=12 Crystallization . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.2 The Calculus of Latent Heat . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5 The Polycrystalline Vacuum: Restoring Lorentz Invariance 7
5.1 Kibble-Zurek Nucleation and Grain Boundaries . . . . . . . . . . . . . . . 7
5.2 Macroscopic Isotropy and the Emergence of c . . . . . . . . . . . . . . . . 7
6 Equivalence Mapping to Standard Cosmology 8
7 Conclusion 9
2
1 Introduction: The Structural Evolution of Space-
time
The inflationary framework represents a foundational pillar of modern cosmology, ele-
gantly solving the flatness, horizon, and magnetic monopole issues inherent in the stan-
dard Big Bang theory [1, 2]. However, it achieves this at a significant theoretical cost: it
requires the universe to be dominated by a hypothetical scalar field (the inflaton) gov-
erned by a highly constrained and fine-tuned potential. We suggest a paradigm shift:
what if inflation and reheating are not driven by novel, undiscovered particle fields, but
rather by the structural, geometric phase transitions of discrete spacetime itself?
Approaches to quantum gravity—ranging from Penrose’s original spin networks [4] and
Loop Quantum Gravity [5] to Causal Dynamical Triangulations (CDT) [8] and modern
holographic tensor networks [6]—increasingly converge on the premise that the vacuum is
not a continuous C
manifold. Instead, it is an emergent, discrete network of quantum
information. If spacetime emerges from a discrete graphical substrate, its early evolution
must be strictly governed by the statistical mechanics of graph topology [7].
In this framework, the universe does not simply nucleate into existence with three flat
macroscopic dimensions. It evolves through a strict thermodynamic sequence dictated by
energy minimization, geometric frustration, and holographic dimensional projection. We
demonstrate that the major epochs of the early universe map rigorously to the sequential
crystallization of specific coordination numbers: K = 6 (Planck era 2D flatness), K = 4
(De Sitter inflation via rapid 3D layer stacking), and K = 12 (Big Bang reheating).
2 Phase I: The Euler Proof of Cosmic Flatness and
Genesis
2.1 The Network Hamiltonian
Consider the pre-geometric vacuum as a dynamic graph G(V, E) evolving under a stabilizer-
type Hamiltonian. The network naturally seeks to maximize discrete quantum entan-
glement (represented by the edges, E) while remaining subject to localized geometric
restrictions. The generalized energy functional can be written as:
H = ϵ
X
i,j
A
ij
+ λ
X
v
Φ(K
v
) (1)
where ϵ represents the binding energy of a single unitary entanglement link (the sole
continuous free parameter of this framework), A
ij
is the adjacency matrix, and Φ(K
v
)
acts as a steep quadratic penalty function preventing infinite local node density, heavily
restricting the local coordination number K
v
[9].
2.2 Proving the K=6 Flatness Constraint
The cosmological Flatness Problem, initially formalized by Dicke and Peebles [3], ques-
tions why the observable universe exhibits a spatial curvature parameter of precisely
k
= 0 ±0.002 [10]. In a continuum manifold, this requires an almost absurd fine-tuning
of initial mass-energy conditions. In our discrete model, spatial flatness is not a coinci-
dence; it is a topological absolute derived directly from the ground-state Hamiltonian.
3
Nature is notoriously economical. In the extreme low-energy, pre-volumetric state, the
nascent network seeks to close minimal entanglement loops (triangles) without inducing
3D spatial stress. The global topology of a 2D triangulated surface is dictated by the
Euler characteristic χ:
χ = V E + F (2)
For a closed manifold constructed entirely of triangles, 3F = 2E. Furthermore, the total
number of edges is related to the average vertex coordination number by 2E = V K.
Substituting these relations into the Euler formula yields the exact macroscopic curvature
of the network:
χ = V
1
K
6
(3)
Because transverse (out-of-plane) dimensionality carries a massive entropic penalty in
the early universe, the Hamiltonian strictly minimizes to a 2D state. Furthermore, because
the Hamiltonian actively maximizes local entanglement loops (driving the network toward
a fully triangulated state rather than sparse K = 3 trees or K = 4 square lattices), the
local penalty Φ(K
v
) forces the lattice into the densest possible 2D triangulated packing:
the flat hexagonal plane, where K = 6. By Eq. 3, setting K = 6 identically forces
χ 0. Therefore, the fundamental ground state of the universe is strictly
geometrically flat. When subsequent quantum fluctuations finally force out-of-plane
nucleation, the resulting 3D volume inherits the exact zero-curvature boundary condition
of its 2D foundation, resolving the Flatness Problem geometrically.
2.3 Resolution of the Big Bang Singularity (The 1/
3 Cutoff)
Standard continuous cosmology extrapolates the expanding universe backward in time to
an unphysical zero-dimensional singularity of infinite density. However, discrete lattice
geometry forbids this. A recent computational analysis of the Selection-Stitch kinematics
reveals a strict topological breaking point when the network is geometrically compressed
[16].
For a foundational lattice defined by equilateral triangles of length L, the geometric
distance from the vertices to the centroid is exactly 1/
3 0.577L. If the universe
is compressed beyond this exclusion threshold, the 3D geometric stability shatters, and
nodes are forced to collapse flatly into the 2D faces of adjacent layers. Consequently,
a classical 0D singularity is mathematically impossible. Gravitational reversal forces a
dimensional reduction: the hot, dense 3D bulk undergoes a phase transition back into the
foundational 2D planar sheet (K = 6). Genesis, therefore, begins as a two-dimensional
holographic boundary, not an infinitely dense point.
3 Phase II: Tetrahedral Foam and Geometric Infla-
tion
3.1 Holographic Nucleation and the Regge Deficit Angle
As the two-dimensional planar network complexifies, stochastic quantum fluctuations in-
evitably bridge the entropic barrier, forcing the nucleation of out-of-plane vertices. This
represents the activation of a holographic “Lift” operator [16], projecting new layers into
the Z-axis to rapidly construct three-dimensional volume from 2D planar components.
4
The minimal, most structurally rigid 3D simplex created by this stacking is the regular
tetrahedron (K = 4). This transition from a 2D sheet to a 3D tetrahedral foam marks
the onset of the volumetric universe. However, a profound geometric constraint governs
our world: regular tetrahedra simply cannot smoothly tile 3D Euclidean space. A sim-
ilar geometric frustration haunts the tetrahedral foam. The dihedral angle of a regular
tetrahedron is:
θ = arccos
1
3
70.528
1.23 rad (4)
Packing five tetrahedra around a shared central edge consumes 5 × 70.528
= 352.64
.
The network fails to close, leaving an unavoidable geometric void. In Regge calculus [11],
this is formalized as the deficit angle δ:
δ = 2π 5θ 7.356
+0.128 rad (5)
3.2 De Sitter Expansion and the Exact Derivation of n
s
The frustrated network’s structural attempt to forcibly close these 0.128-radian gaps acts
as a compressed geometric spring. To eliminate arbitrary parameters, we define the
fundamental lattice spacing identically as the bare Planck length (L l
P
). In discrete
lattice gravity, the scalar curvature R at a hinge is defined by the deficit angle divided
by its associated area [12]. For a lattice of Planck-scale simplices, the local macroscopic
curvature scales directly as:
R
local
δ
l
2
P
0.128
l
2
P
(6)
Assuming the emergent macroscopic spacetime behaves as a four-dimensional manifold
(three spatial dimensions evolving in time), a vacuum characterized by a constant positive
scalar curvature is uniquely a De Sitter spacetime, where the effective Cosmological Con-
stant
eff
) is geometrically locked to the Ricci scalar via R = 4Λ. Thus, the topological
frustration generates a dimensionally exact effective cosmological constant:
Λ
eff
R
local
4
0.032
l
2
P
(7)
It is crucial to note that this represents the primordial, Planck-scale inflationary cos-
mological constant ( 10
68
m
2
), which is roughly 10
120
orders of magnitude larger than
the late-time observed dark energy density. Substituting this strictly positive, geometri-
cally fixed vacuum constant into the Friedmann equations yields an unbraked, exponential
expansion:
a(t) e
H
inf
t
where H
inf
p
Λ
eff
(8)
Consequently, Cosmic Inflation requires no ad-hoc scalar field. It is the rigorous, mechan-
ical expansion of a geometrically frustrated K = 4 topological glass struggling to heal its
own metric gaps as new 2D layers are holographically nucleated into the 3D bulk.
Crucially, this geometric framework provides a parameter-free derivation of the scalar
spectral index (n
s
). In the foundational 2D phase (K = 6), the perfectly flat planar
geometry natively yields exact scale invariance (n
s
= 1.0). The observed “red tilt” (de-
parture from scale invariance) is strictly generated by the holographic projection into the
3D tetrahedral foam.
The spectral tilt represents the fractional metric perturbation per fundamental spatial
cell. In the SSM, this perturbation is precisely the Regge deficit angle (δ) measured in
5
units of the natural gauge boundary of the foundational 2D triangular face—specifically,
its circumscribed perimeter (C = 2πR
circ
). As established in Section 2.3, the circumradius
of the unitary triangle is R
circ
= 1/
3L. The fractional departure from scale invariance
is therefore the ratio of the 3D volumetric gap to this 2D boundary condition:
1 n
s
=
δ
2πR
circ
=
3δ
2π
(9)
Inserting the exact Regge deficit angle of the regular tetrahedron (δ 0.128388 rad)
yields:
n
s
= 1
3(0.128388)
2π
0.96461 (10)
This pure geometric derivation lands an astonishing 0.07σ from the European Space
Agency’s Planck 2018 legacy central value (n
s
= 0.9649 ± 0.0042) [10].
Furthermore, because the deficit angle δ is a fixed structural constant of the K = 4
lattice rather than a dynamic field rolling down a potential gradient, the standard slow-roll
parameter ϵ
V
0. This dictates that inflation in the SSM is strictly η-dominated, yielding
a predicted tensor-to-scalar ratio of r 0.005. This value satisfies current BICEP/Keck
constraints (r < 0.036) and serves as a hard, falsifiable prediction for upcoming next-
generation CMB observatories (e.g., LiteBIRD, CMB-S4). Thus, the observed CMB power
spectrum is not the signature of a decaying scalar particle, but the direct topological
shadow of the tetrahedral packing defect embedded during the vacuum’s holographic 3D
nucleation.
4 Phase III: Saturation and Reheating
4.1 The K=12 Crystallization
As the unbraked tetrahedral foam expands, it generates new nodes to locally bridge its
deficit angles. Eventually, the localized node density reaches the absolute saturation limit
for 3D space. At this critical threshold, the frustrated K = 4 glass can no longer sustain
its chaotic configuration. It undergoes a violent, global first-order phase transition [13].
To perfectly eliminate the deficit angles and reach the true free-energy minimum, the
nodes collectively crystallize into the Face-Centered Cubic (FCC) lattice, defined by the
Cuboctahedron unit cell (K = 12). A computational analysis of the Selection-Stitch
mechanism confirms that 2D-dominant holographic growth coupled with entanglement-
driven proximity bonding flawlessly self-assembles this saturated K = 12 spatial geometry
[16].
4.2 The Calculus of Latent Heat
In standard theories, inflation ends when the inflaton arbitrarily decays, transferring its
energy into a thermal bath (reheating) [15]. In our geometric model, reheating is strictly
the latent heat of crystallization released by the topological phase transition. When
water freezes into ice, it releases latent heat into its surroundings. The crystallization of
the vacuum operates identically.
We can calculate this exactly using our single free parameter: the unitary stitch energy
ϵ. Currently, ϵ must be fitted to observational constraints rather than derived from first
6
principles. In the K = 4 foam, each node possesses 4 half-bonds, yielding a structural
binding energy of E
K=4
= 2ϵ per node. In the fully saturated K = 12 FCC lattice, each
node achieves 6 full bonds, yielding E
K=12
= 6ϵ per node. The instantaneous fusion of
the geometric gaps releases a specific latent heat Q per node:
Q = E
K=12
E
K=4
= (6 2)ϵ = 4ϵ (11)
This massive release of topological binding energy completely thermalizes the newly
formed continuous spatial grid, generating the hot primordial plasma of the Big Bang. If
we constrain the single free parameter ϵ to operate near the Grand Unified Theory (GUT)
scale ( 10
15
GeV), the resulting geometric energy dump yields an ambient thermal bath
of:
T
reheat
10
15
GeV (12)
This phenomenologically fitted temperature matches the strict upper bounds required by
standard ΛCDM to successfully preserve Big Bang Nucleosynthesis (BBN) [15].
5 The Polycrystalline Vacuum: Restoring Lorentz
Invariance
5.1 Kibble-Zurek Nucleation and Grain Boundaries
A fundamental challenge for any discrete spacetime model is the recovery of continuous
Lorentz invariance at macroscopic scales. A single, universe-spanning perfect FCC (K =
12) crystal inherently possesses preferred directional axes, violating the strict rotational
symmetry (SO(3)) and isotropic speed of light required by Special Relativity.
However, the geometric phase transition from the K = 4 foam to the K = 12 lattice
does not occur as a single monolithic event. Following the Kibble-Zurek mechanism [13,
14], the crystallization nucleates simultaneously at countless causally disconnected regions
across the expanding De Sitter horizon. As these independent K = 12 vacuum bubbles
expand, they possess random spatial orientations. When these expanding domains collide,
they cannot perfectly align, resulting in a polycrystalline vacuum. The universe is thus
composed of randomly oriented microscopic K = 12 domains, separated by topological
grain boundaries.
5.2 Macroscopic Isotropy and the Emergence of c
While a single K = 12 domain possesses a discrete, anisotropic metric tensor g
(i)
µν
, the
macroscopic metric g
µν
observed by low-energy (long-wavelength) physics is the volu-
metric average over billions of randomly oriented domains. Let the orientation of the i-th
domain be defined by a rotation matrix R
i
SO(3). The macroscopic effective metric is
the spatial ensemble average:
g
µν
=
1
V
X
i
R
T
i
g
(i)
µν
R
i
V
i
(13)
Because the nucleation orientations R
i
are uniformly distributed across the SO(3) group,
the discrete directional biases cancel out entirely upon integration over any macroscopic
7
volume. The spatial averaging of the lattice tensor rigorously converges to the continuous,
isotropic Minkowski metric:
g
µν
η
µν
(14)
While spatial SO(3) averaging rigorously guarantees macroscopic spatial isotropy, re-
covering full SO(3, 1) Lorentz boost invariance is a strictly stronger requirement. We
postulate that because the boundaries of these random domains carry no net preferred
momentum, the invariant speed of light c emerges as the strict macroscopic limit of the
polycrystalline tensor network. A complete mathematical proof of emergent hyperbolic
boost symmetry remains an open topological challenge, but macroscopic spatial isotropy
is definitively guaranteed by the model.
6 Equivalence Mapping to Standard Cosmology
To ensure conceptual clarity and foster integration with established astrophysical lit-
erature, we explicitly define the formal correspondence between the continuous fields of
standard cosmology and the discrete topological mechanisms proposed herein. As demon-
strated in Table 1, our geometric framework does not invalidate standard continuum dy-
namics; rather, it provides a deeper, mechanical engine for the accepted cosmological
epochs.
Cosmological
Epoch
Standard Continuum Mech-
anism (ΛCDM)
Discrete Geometric Mecha-
nism (Tensor Network)
Initial Singular-
ity
Mathematical point of infinite
mass density and undefined ge-
ometry.
Geometric cutoff at 1/
3L pre-
venting infinite collapse, yield-
ing a 2D planar boundary state.
Planck Era
(Flatness Origin)
Fine-tuned uniform flat bound-
ary conditions (Ω
k
= 0).
Euler topological limit (χ
0) of the 2D hexagonal Genesis
state (K = 6).
Cosmic Inflation Hypothetical scalar Inflaton
field driving negative vacuum
pressure.
Regge deficit angle (δ +0.128)
of the K = 4 tetrahedral foam
generating positive scalar curva-
ture.
Big Bang
(Reheating)
Ad-hoc scalar field decay trans-
ferring energy to standard par-
ticles.
Exact latent heat of crystalliza-
tion (∆Q = 4ϵ) yielding a ther-
mal bath of T
reheat
10
15
GeV.
Onset of
FLRW Gravity
Assumed universal transition to
radiation/matter domination.
Macroscopic structural tension
established by contiguous K =
12 FCC spatial locking.
Table 1: A formal equivalence mapping between the standard continuum inflationary
paradigm and the discrete geometric phase transitions of the quantum tensor network.
The establishment of continuous macroscopic lattice connectivity generates global
structural tension. This metric tension acts as the ultimate braking mechanism that in-
8
stantly halts the exponential De Sitter expansion, forcing the universe to seamlessly transi-
tion into the decelerating, radiation-dominated FLRW continuum governed by a(t) t
1/2
.
By providing a rigid, polycrystalline background geometry, this K = 12 phase serves ex-
actly as the continuous target manifold sought by Causal Dynamical Triangulations [8].
7 Conclusion
By subjecting the vacuum to the statistical mechanics of discrete graph topology, the
phenomenological parameter space of early universe cosmology can be replaced entirely
by rigid topological phase transitions:
1. Singularity Resolution: The geometric cutoff of the exclusion principle at 1/
3L
mathematically forbids a zero-dimensional point of infinite density, ensuring the
universe stems from a finite dimensional plane.
2. Cosmic Flatness (
k
= 0): Uniquely proven by the Euler characteristic of the
absolute minimal-energy 2D ground state (K = 6).
3. Cosmic Inflation (n
s
0.9646): Mechanically driven by the constant positive
scalar curvature resulting from the precise +0.128-radian Regge deficit angle of
the K = 4 tetrahedral foam. This topological defect perfectly predicts the scalar
spectral index and a tensor-to-scalar ratio of r 0.005 without free parameters.
4. Reheating (T 10
15
GeV): Derived exactly as the 4ϵ latent heat of crystallization
released when the vacuum snaps into the stable K = 12 continuum.
5. Lorentz Invariance: Naturally recovered via the macroscopic SO(3) rotational
averaging of the globally isotropic polycrystalline structure driven by Kibble-Zurek
nucleation.
This framework provides a mathematically constrained foundation for the origin of
the universe, rooted natively in the proven limits of spatial topology. While critical steps
remain—most notably the derivation of the full SO(3, 1) Lorentz boost invariance—the
computational verification of the holographic dimensional projection provides a rigorous
physical justification for the Holographic Principle. Furthermore, the parameter-free ge-
ometric derivation of the scalar spectral index (n
s
) precisely aligns with observational
cosmology. Localized 3D mass-energy defects (particles) within the K = 12 bulk will
naturally find their information capacity strictly bounded by their 2D topological surface
area, a principle that paves the way for deriving the hadronic mass spectrum strictly from
lattice geometry.
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