More on the first-order thermodynamics of scalar-tensor and Horndeski gravity
Valerio Faraoni, Julien Houle
Abstract
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 be fully legitimate and then extended to all Bianchi universes. It is shown that the formalism holds thanks to the almost miraculous fact that the constitutive relations of Eckart's thermodynamics are satisfied, while writing the field equations as effective Einstein equations with an effective dissipative fluid does not contain new physics.
Topics & Concepts
Friedmann–Lemaître–Robertson–Walker metricDissipative systemPhysicsCosmologyFormalism (music)Scalar fieldMathematical physicsField equationClassical mechanicsExtended irreversible thermodynamicsGravitationTheoretical physicsThermodynamicsNon-equilibrium thermodynamicsQuantum mechanicsMusicalVisual artsArtCosmology and Gravitation TheoriesBlack Holes and Theoretical PhysicsRelativity and Gravitational Theory