# Equilibrium Thermodynamics and Neutrino Decoupling in Quasi-Metric Cosmology

## TL;DR

This paper examines thermodynamics and neutrino decoupling in quasi-metric cosmology, revealing conflicts with observed neutrino backgrounds and questioning the viability of the framework without exotic neutrino physics.

## Contribution

It formulates thermodynamics within the quasi-metric framework and analyzes neutrino decoupling, highlighting fundamental differences from standard cosmology and experimental inconsistencies.

## Key findings

- Quasi-metric cosmology predicts identical neutrino energies today and after decoupling.
- Predicted relic neutrino background conflicts with solar neutrino detection data.
- Without exotic neutrino decay, quasi-metric cosmology is incompatible with observations.

## Abstract

The laws of thermodynamics in the expanding universe are formulated within the quasi-metric framework. Since the quasi-metric cosmic expansion does not directly influence momenta of material particles, so that the expansion directly cools null particles only (e.g., photons), these laws differ substantially from their counterparts in standard cosmology. In particular, all non-null neutrino mass eigenstates are predicted to have the same energy today as they had just after neutrino decoupling in the early universe. As a result, the predicted relic neutrino background is strongly inconsistent with detection rates measured in solar neutrino detectors (Borexino in particular). Thus quasi-metric cosmology is in violent conflict with experiment unless some exotic property of neutrinos makes the relic neutrino background essentially undetectable (e.g., if all massive neutrino mass eigenstates decay into "invisible" particles over cosmic time scales). But in the absence of experimental confirmation of the necessary exotic neutrino physics needed to resolve said conflict, the current status of quasi-metric relativity has been changed to non-viable.