Quantum phenomenological gravitational dynamics: A general view from thermodynamics of spacetime

Abstract

In this work we derive general quantum phenomenological equations of gravitational dynamics and analyse its features. The derivation uses the formalism developed in thermodynamics of spacetime and introduces low energy quantum gravity modifications to it. Quantum gravity effects are considered via modification of Bekenstein entropy by an extra logarithmic term in the area. This modification is predicted by several approaches to quantum gravity, including loop quantum gravity, string theory, AdS/CFT correspondence and generalised uncertainty principle phenomenology, giving our result a general character. The derived equations generalise classical equations of motion of unimodular gravity, instead of the ones of general relativity, and they contain at most second derivatives of the metric. We provide two independent derivations of the equations based on thermodynamics of local causal diamonds. First one uses Jacobson's maximal vacuum entanglement hypothesis, the second one Clausius entropy flux. Furthermore, we consider questions of diffeomorphism and local Lorentz invariance of the resulting dynamics and discuss its application to a simple cosmological model, finding a resolution of the classical singularity.

arXiv commentExtended discussions, extra references added. 31 pages, 1 figure

References in corpus (11)

• Thermodynamics of Spacetime: The Einstein Equation of State
• Entropy and Area
• Quantum gravity and minimum length
• Thermodynamical Aspects of Gravity: New insights
• The Thermodynamics of Black Holes
• Black hole entropy in Loop Quantum Gravity
• Entanglement entropy of black holes
• When conceptual worlds collide: The GUP and the BH entropy
• Horizon Entropy
• Geometry of small causal diamonds
• Area deficits and the Bel-Robinson tensor

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• On the microstructure of higher-dimensional Reissner-Nordström black holes in quantum regime
• Friedmann equations and cosmic bounce in a modified cosmological scenario
• Thermodynamics as a tool for (quantum) gravitational dynamics
• Emergence of quadratic gravity from entanglement equilibrium
• Gravity from thermodynamics in vacuum: Lorentz invariance and the role of Bel-Robinson tensor
• Mass-to-Horizon Relation and Entropy Beyond the Bekenstein-Hawking Limit
• Thermodynamics of spacetime from minimal area