
on the lattice. The reasoning is as follows: the Cosserat lattice dispersion (Eq. (16)) carries
a correction
(kL)
2
. When this correction is evaluated at the wavenumber
k
c
= mc/ℏ
the
reduced Compton scale, the intrinsic rest-energy wavevector of the excitation it becomes
(m/m
soft
)
2
. The conjecture is that as this ratio crosses unity the excitation ceases to be
cleanly representable: a reversible deformation sets in, growing until representability fails
outright at the hard threshold. We emphasize that
this is a conjecture, not a derivation
: a
rst-principles treatment would have to derive the representability bound from the lattice
response itself the long-wavelength Green's function of the
K = 12
network evaluated at
the rest-energy scale which we do not do here. We treat Eq. (20) as a phenomenological
rate law motivated by the lattice geometry.
The central hypothesis: Compton representability.
The weakest step in this chain is
the choice of length scale, and we state it plainly. Because the lattice
is
the vacuum rather
than an environment external to the object, the relevant question is not how a center-of-
mass superposition couples to a bath. That would be an ordinary decoherence process, and
such processes are governed by the spatial
delocalization
∆x
between branches, which is set
by trap geometry and is orders of magnitude larger than any lattice scale. The question is
instead whether each branch, on its own, is coherently representable as a lattice excitation
and that single-branch question carries no
∆x
: branch separation says how far apart
two independently-representable copies are placed, not whether either is representable. We
posit that representability is controlled by the
reduced Compton wavelength
λ
c
= ℏ/(mc)
,
the intrinsic rest-energy wavelength of the excitation, and fails once
λ
c
is no longer resolv-
able by the FCC geometry: the soft threshold at
λ
c
= L
, the hard threshold at
λ
c
= L/
√
3
.
This is a hypothesis, not a theorem; it treats the macroscopic center-of-mass mode as a
single excitation characterized by its total rest energy, and it is what an experiment in the
13.1
22.6 µ
g window would test. We do not derive it, and the falsiable content (the
√
3
ratio and the two-step prole) stands or falls with it. Its distinctive, testable signature
is precisely the
absence
of
∆x
-dependence that an environmental-coupling model would
predict. The next subsection collects the physical motivations for this choice of scale and
addresses the natural objections to it.
7.1 Why the Compton scale and not the trap scale
The natural objection to P3 is best stated at once. In standard quantum mechanics
the spatial extent of a center-of-mass wavefunction is set by external potentials trap
frequencies and not by the Compton wavelength; the rest mass of a
10 µ
g object certainly
does not conne its wavepacket to a Planck-scale packet. If P3 claimed spatial pinching, it
would simply be wrong. It does not. Four observations locate the actual physical content
of the hypothesis; we present them as motivations, not derivations.
(i) The mass term is a clock, not a packet width.
Any excitation of mass
m
whatever its spatial envelope carries a rest-energy phase evolving at the Compton
frequency
Ω = mc
2
/ℏ
. This internal clock is standard quantum mechanics: it is the de
Broglie phase of the massive state, and interferometry has been performed directly against
it [10]. On the lattice, the update interval is
τ = 4L/c
(Section 3), so the dimensionless
product is
Ωτ = 4 (m/m
soft
)
: the soft threshold is the mass at which the center-of-mass
mode's phase clock reaches the lattice's temporal bandwidth (
Ωτ = 4
), and the hard
threshold corresponds to
Ωτ = 4
√
3
. A discrete network cannot faithfully track a phase
rotating faster than its refresh rate, in direct analogy with sampling above the Nyquist
limit. The reduced Compton wavelength enters as
c/Ω
the spatial period of this phase
10