A thermodynamics revision of Rastall gravity

Abstract

In this work we study some aspects of the Rastall gravity, being the thermodynamics consistency of the model the core of this paper, for this purpose we will consider the dynamical equations of Rastall model in a flat FLRW geometry. Under a holographic description can be seen that this scenario for gravity contributes to the energy density of the fluid with an extra term that can be related to the deceleration parameter, providing a way to estimate the value of the Rastall parameter, termed as $\xi \lambda$, at present time. By adopting a specific Ansatz for the $\xi \lambda$ term it is possible to determine that the behaviour of the Hubble parameter in Rastall gravity has a similar aspect to the $\Lambda$CDM model at late times, but at thermodynamics level differs from the standard cosmology since the adiabatic behaviour for the entropy depends on the value of the parameter state, $\omega$. However, the entropy has a positive growth and simultaneously its convexity condition can be guaranteed; when other contributions are considered such as matter production and chemical potential, the adiabatic expansion can not be achieved, but the theory keeps its thermodynamics consistency. The chemical potential seems to have an interesting role since at effective level we could have a cosmological constant or phantom expansion in the model.

11 pages, 2 figures, accepted version in CQG

References in corpus (12)

• f(R,T) gravity
• f(R,L_m) gravity
• Einstein and Rastall Theories of Gravitation in Comparison
• Unified dark energy thermodynamics: varying w and the -1-crossing
• Thermodynamics in Rastall Gravity with Entropy Corrections
• Cosmological consequences in the framework of generalized Rastall theory of gravity
• Chemical Potential and the Nature of the Dark Energy: The case of phantom
• Crossing the phantom divide with dissipative normal matter in the Israel-Stewart-Hiscock formalism
• Dark energy and Dark matter interaction in light of the second law of thermodynamics
• Thermodynamically allowed phantom cosmology with viscous fluid
• Does the second law hold at cosmic scales?
• A holographic cut-off inspired in the apparent horizon

Cited by in corpus (8)

• Horizon-scale tests of gravity theories and fundamental physics from the Event Horizon Telescope image of Sagittarius A${}^{\ast }$
• Non-trivial class of anisotropic compact stellar model in Rastall gravity
• Challenging matter creation models in the phantom divide
• Quasinormal Modes and Greybody factors of de Sitter Black holes surrounded by Quintessence in Rastall gravity
• Cosmic expansion with matter creation and bulk viscosity
• Quadratic Rastall Gravity: from low-mass HESS J1731-347 to high-mass PSR J0952-0607 pulsars
• Generalized Misner-Sharp energy in the generalized Rastall theory
• Exploring thermodynamics inconsistencies in unimodular gravity: a comparative study of two energy diffusion functions