We delve into the first-order thermodynamics of Horndeski gravity, focusing on spatially flat,
homogeneous, and isotropic cosmologies. Our exploration begins with a comprehensive …

We extend to the Horndeski realm the irreversible thermodynamics description of gravity
previously studied in “first generation” scalar-tensor theories. We identify a subclass of …

A new thermodynamics of scalar-tensor gravity is applied to spatially homogeneous and
isotropic cosmologies in this class of theories and tested on analytical solutions. A forever …

We revisit the analogy between a minimally coupled scalar field in general relativity and a
perfect fluid, correcting previous identifications of effective temperature and chemical …

Two issues in the first-order thermodynamics of scalar-tensor (including “viable” Horndeski)
gravity are elucidated. The application of this new formalism to FLRW cosmology is shown to …

We investigate a puzzle in the recent thermodynamics of scalar-tensor gravity, in which
general relativity is a zero-temperature state of equilibrium and scalar-tensor gravity is the …

In the context of the recently proposed first-order thermodynamics of scalar-tensor gravity,
we discuss the possibility of zero-temperature states of equilibrium other than Einstein …

Stealth solutions of scalar-tensor gravity and less-known de Sitter spaces that generalize
them are analyzed regarding their possible role as thermal equilibria at non-zero …

Disformal transformations of Friedmann-Lemaître-Robertson-Walker and Bianchi
geometries are analyzed in the context of scalar-tensor gravity. Novel aspects discussed …

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 …