
Late-Universe Dynamics from Vacuum Geometry:
Unifying Dark Energy and the Hubble Tension via a
Discrete Topological Phase Transition
Raghu Kulkarni
SSMTheory Group, IDrive Inc., Calabasas, CA 91302, USA
raghu@idrive.com
Abstract
Two stubborn problems sit at the heart of modern cosmology: the 10
120
-fold gap be-
tween the predicted and observed vacuum energy, and the 5σ Hubble tension between
early-universe (H
0
≈ 67.4 km s
−1
Mpc
−1
) [1] and late-universe (H
0
≈ 73.0 km s
−1
Mpc
−1
)
[2] measurements. We argue that both arise from one geometric phase transition
in a discrete Face-Centered Cubic (FCC) vacuum lattice with coordination number
K = 12. Computational lattice simulations confirm the internal bulk sheets are
exactly flat (σ
z
< 10
−10
L), meaning the bulk carries zero vacuum stress (Λ
bulk
= 0).
Dark energy is therefore confined to the elastic bending strain of the outermost holo-
graphic boundary shell, yielding a bare tension Ω
Λ,bare
≈ 0.623. Non-linear structure
formation in the late universe punches macroscopic voids through this lattice, break-
ing the local O
h
symmetry and unlocking one extra expansion channel—from 12 to
13 active nodes per unit cell. That single integer ratio amplifies the CMB base-
line to H
pred
0
= 67.4 ×13/12 ≈ 73.02 km s
−1
Mpc
−1
with no adjustable parameters,
and simultaneously renormalizes the boundary tension to Ω
Λ
≈ 0.675. The frame-
work predicts environmentally dependent H
0
values and a thawing equation of state
w(z) ≈ −1 + (1/12)(1 + z)
−3
, consistent with recent extended DESI DR2 BAO
evidence for dynamical dark energy at low redshift [19].
Keywords: cosmological parameters, dark energy, large-scale structure, tensor networks,
vacuum geometry
1 Introduction
ΛCDM works remarkably well as a bookkeeping device for the large-scale universe. It does
not, however, explain its own parameters. Two of those parameters have become genuine
crises. The Cosmological Constant Problem has been with us since Weinberg’s [3] seminal
analysis: quantum field theory predicts a vacuum energy density roughly 10
120
times larger
than what drives the observed accelerated expansion (Ω
Λ
≈ 0.685 [1]). Decades of effort
have not produced a convincing cancellation mechanism.
The Hubble Tension is younger but no less severe. The Planck CMB measurement
gives H
0
≈ 67.4 km s
−1
Mpc
−1
[1], while the SH0ES distance-ladder programme finds
H
0
= 73.04 ±1.04 km s
−1
Mpc
−1
[2]—a 5σ gap. Recent JWST TRGB measurements land
in between at H
0
≈ 69.8 ± 1.6 km s
−1
Mpc
−1
[4], sustaining rather than resolving the
debate. For a comprehensive review, see Verde et al. [5]. Proposed fixes typically involve
early dark energy, additional relativistic species, or modified recombination physics—each
introducing new free parameters without a clear physical motivation.
In this paper we take a different path. We treat the vacuum not as a featureless
continuum, but as a discrete crystalline lattice whose microstructure has macroscopic
1