Neutrino Cosmology in Lava-Void Theory
December 20, 2025
Entropy and the Arrow of Time in Lava-Void Cosmology
December 20, 2025
Lava-Void Cosmology and Cosmic Reionization
By C. Rich
Lava-Void Cosmology Cosmic Reionization provides a unified explanation for late, rapid ionization driven by viscous structure formation. To integrate cosmic reionization and post-recombination opacity into Lava-Void Cosmology while preserving the unified relativistic viscous fluid framework, the reionization process emerges from enhanced early formation of massive structures driven by viscous clustering in dense regions.
The model’s existing resolution of JWST-observed “universe-breaker” galaxies, through density-dependent fluid thickening acting as an effective cold dark matter analog, naturally produces abundant high-mass halos at \( z > 10 \). These structures host efficient star formation and UV photon escape, leading to patchy ionization bubbles that grow and merge, completing reionization rapidly at late times with midpoint \( z_{\rm re} \approx 7.5 \) and endpoint by \( z \approx 6 \).
This mechanism aligns with recent observational preferences for a late and rapid reionization scenario driven by massive galaxies, yielding a low electron scattering optical depth \( \tau \approx 0.052\text{–}0.06 \), consistent with constraints from Planck CMB, ACT/SPT polarization, JWST luminosity functions, and HERA/LOFAR 21 cm limits.
Mathematical Formulation
The volume filling factor of ionized regions \( Q(z) \) follows
\[
\frac{dQ}{dz} =
\frac{\dot{n}_{\rm ion}}{n_H}
– \alpha_B n_H (1+z)^3 Q x_e
\]
where the ionizing photon production rate is
\[
\dot{n}_{\rm ion}
= f_{\rm esc} \, \zeta \, \dot{\rho}_*
\]
In the viscous fluid paradigm, the ionization efficiency scales with clustered density as
\[
\zeta(\rho) \propto \rho_{\rm clustered}^{\gamma},
\quad \gamma > 0
\]
A flexible parametrization for the ionization fraction is
\[
x_e(z) =
\frac{1}{2}
\left[
1 + \tanh\left(\frac{z_{\rm re} – z}{\Delta_z}\right)
\right]
\]
The Thomson optical depth to reionization is
\[
\tau =
\int_0^{z_{\rm rec}}
\sigma_T \, n_e(z)
\frac{c \, dz}{H(z)(1+z)}
\]
with the electron density given by
\[
n_e(z) = x_e(z) \, n_H(z)
\]
The 21 cm differential brightness temperature offset is
\[
\delta T_b(\nu) \approx
27 \, x_{\rm HI} (1+\delta)
\left(\frac{\Omega_b h^2}{0.02}\right)
\left(\frac{1+z}{10}\right)^{1/2}
\left(1 – \frac{T_\gamma}{T_s}\right)
\, {\rm mK}
\]
The patchy kSZ contribution to CMB anisotropies scales as
\[
\Delta C_\ell^{\rm kSZ}
\propto \tau \, Q \, \Delta v^2
\]
Numerical extensions using semi-numeric simulations adapted to viscous halo catalogs can forward-model these observables, constraining parameters for consistency with low-\( \tau \) reionization while predicting enhanced fluctuation signals in 21 cm tomography.
C. Rich
