Thermodynamics of scalar-tensor gravity

  title={Thermodynamics of scalar-tensor gravity},
  author={Valerio Faraoni and Andrea Giusti},
Previously, the Einstein equation has been described as an equation of state, general relativity as the equilibrium state of gravity, and f(R) gravity as a non-equilibrium one. We apply Eckart’s first order thermodynamics to the effective dissipative fluid describing scalar-tensor gravity. Surprisingly, we obtain simple expressions for the effective heat flux, “temperature of gravity”, shear and bulk viscosity, and entropy density, plus a generalized Fourier law in a consistent Eckart… Expand
First-order thermodynamics of Horndeski gravity
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 Horndeski theoriesExpand
A new approach to the thermodynamics of scalar-tensor gravity
We further develop the recently proposed thermodynamics of scalar-tensor gravity and investigate its diffusion toward general relativity, seen as a thermal equilibrium state. Describing scalar-tensorExpand
Microphysical manifestations of viscosity and consequences for anisotropies in the very early universe
It has been known that a non-perfect fluid that accounts for dissipative viscous effects can evade a highly anisotropic chaotic mixmaster approach to a singularity. Viscosity is often simplyExpand


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