Alternative formulations of the thermodynamics of scalar-tensor theories
arXiv:2405.20865 · doi:10.1103/PhysRevD.110.064087
Abstract
We explore alternative formulations of the analogy between viable Horndeski gravity and Eckart's first-order thermodynamics. We single out a class of identifications for the effective stress-energy tensor of the scalar field fluid that, upon performing the imperfect fluid decomposition, yields constitutive relations that can be mapped onto Eckart's theory. We then investigate how different couplings to Einstein's gravity, at the level of the field equations, can affect the thermodynamic formalism overall. Last, we specialize the discussion to the case of ``traditional'' scalar-tensor theories and identify a specific choice of the coupling function that leads to a significant simplification of the formalism.
arXiv comment11 pages. Matches published version in Phys. Rev. D
References in corpus (12)
- Thermodynamics of Spacetime: The Einstein Equation of State
- Imperfect Dark Energy from Kinetic Gravity Braiding
- Non-equilibrium Thermodynamics of Spacetime
- Hawking Radiation and Black Hole Thermodynamics
- Imperfect fluid description of modified gravities
- First-order thermodynamics of Horndeski gravity
- Thermodynamics of scalar-tensor gravity
- More on the first-order thermodynamics of scalar-tensor and Horndeski gravity
- Fluid nature constrains Horndeski gravity
- Past-directed scalar field gradients and scalar-tensor thermodynamics
- Thermal stability of stealth and de Sitter spacetimes in scalar-tensor gravity
- First-order thermodynamics of Horndeski cosmology