Conformal Symmetry and Cosmological Entropy Production

TL;DR

This paper explores how conformal symmetry in an isotropic cosmic medium relates to viscous pressure and entropy production, proposing an exactly solvable model linking microscopic forces to cosmic expansion.

Contribution

It introduces a model connecting conformal symmetry, viscous pressure, and entropy production in cosmology, with a novel mechanism involving self-interacting particle forces.

Findings

Conformal symmetry allows negative viscous pressure and entropy production.

A high decay rate of the refraction index can drive inflation.

The model provides an exact solution linking microscopic forces to cosmic dynamics.

Abstract

Introducing an effective refraction index of an isotropic cosmic medium, we investigate the cosmological fluid dynamics which is consistent with a conformal, timelike symmetry of a corresponding ``optical'' metric. We demonstrate that this kind of symmetry is compatible with the existence of a negative viscous pressure and, consequently, with cosmological entropy production. We establish an exactly solvable model according to which the viscous pressure is a consequence of a self-interacting one-particle force which is self-consistently exerted on the microscopic particles of a relativistic gas. Furthermore, we show that a sufficiently high decay rate of the refraction index of an ultrarelativistic cosmic medium results in an inflationary expansion of the universe.