Thermodynamics of scalar-tensor gravity

Abstract

Previously, the Einstein equation has been described as an equation of state, general relativity as the equilibrium state of gravity, and $f(\mathcal{R})$ 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 thermodynamical picture. Well-defined notions of temperature and approach to equilibrium, missing in the current thermodynamics of spacetime scenarios, naturally emerge.

arXiv comment5 pages. Corrected Eq. (26) describing the approach to equilibrium and one typographical error. Matches Letter to appear in Physical Review D

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Cited by in corpus (22)

• First-order thermodynamics of Horndeski gravity
• First-order thermodynamics of scalar-tensor cosmology
• Scalar field as a perfect fluid: thermodynamics of minimally coupled scalars and Einstein frame scalar-tensor gravity
• Microphysical manifestations of viscosity and consequences for anisotropies in the very early universe
• More on the first-order thermodynamics of scalar-tensor and Horndeski gravity
• Fluid nature constrains Horndeski gravity
• Peculiar thermal states in the first-order thermodynamics of gravity
• Thermal stability of stealth and de Sitter spacetimes in scalar-tensor gravity
• Past-directed scalar field gradients and scalar-tensor thermodynamics
• Thermal origin of the attractor-to-general-relativity in scalar-tensor gravity
• First-order thermodynamics of scalar-tensor gravity
• First-order thermodynamics of Horndeski cosmology
• Generalized McVittie geometry in Horndeski gravity with matter
• Alternative formulations of the thermodynamics of scalar-tensor theories
• General analysis of Noether symmetries in Horndeski gravity
• Scalar fluid in scalar-tensor gravity from an equivalent picture of thermodynamic and fluid descriptions of gravitational dynamics
• Eckart heat-flux applicability in $F(\Phi ,X)R$ theories and the existence of temperature gradients
• Thermal channels of scalar and tensor waves in Jordan-frame scalar--tensor gravity
• Thermal description of braneworld effective theories
• A new approach to the thermodynamics of scalar-tensor gravity
• Dynamics of a nonminimally coupled scalar field in asymptotically $Ad{S}_4$ spacetime
• Stealth metastable state of scalar-tensor thermodynamics