Past-directed scalar field gradients and scalar-tensor thermodynamics

TL;DR

This paper extends the thermodynamics framework of scalar-tensor gravity to include scalar fields with past-directed gradients, analyzing implications and revisiting an exact cosmological solution within this context.

Contribution

It introduces a refined thermodynamics approach for scalar-tensor gravity accommodating past-directed scalar gradients, enhancing understanding of cosmological solutions.

Findings

Inclusion of past-directed scalar gradients in thermodynamics

Discussion of implications and subtleties in scalar-tensor theories

Revisiting an exact cosmological solution with new insights

Abstract

We refine and slightly enlarge the recently proposed first-order thermodynamics of scalar-tensor gravity to include gravitational scalar fields with timelike and past-directed gradients. The implications and subtleties arising in this situation are discussed and an exact cosmological solution of scalar-tensor theory in first-order thermodynamics is revisited in light of these results.