New phenomenology in the first-order thermodynamics of scalar-tensor gravity for Bianchi universes

TL;DR

This paper explores the phase space of Bianchi I universes in vacuum Brans-Dicke gravity, revealing new phenomenological behaviors near Einstein solutions through a thermodynamic perspective.

Contribution

It introduces a novel analysis of the phase space in scalar-tensor gravity, connecting fixed points with thermodynamic ideas to uncover new phenomenology.

Findings

Identification of new behaviors near Einstein solutions

Comparison of solution dynamics with thermodynamic concepts

Enhanced understanding of scalar-tensor gravity in anisotropic universes

Abstract

The phase space of Bianchi I universes in vacuum Brans-Dicke gravity is analyzed in terms of physical variables. The behaviour of the solutions of the field equations near the fixed points (which are solutions of Einstein gravity) is compared with basic ideas of the recent first-order thermodynamics of scalar-tensor gravity, elucidating new phenomenology.