### Conveners

#### Black Hole Thermodynamics: Block 1

- Hernando Quevedo (National Autonomous University of Mexico)

#### Black Hole Thermodynamics: Block 2

- Hernando Quevedo (National Autonomous University of Mexico)

### Description

This parallel session will be devoted to physical and mathematical aspects of black hole thermodynamics. Topics of interest include, but are not limited to, different definitions of entropy, fundamental equations, thermodynamic laws and variables, phase transitions, extended phase space, stability properties, and critical coefficients of black holes in any dimension. The session will cover also the development and application of different analytical and geometric methods in the study of black hole thermodynamics.

We reconsider the thermodynamics of AdS black holes in the context of gauge-gravity duality. In this new setting where both the cosmological constant $\Lambda$ and the gravitational Newton constant $G$ are varied in the bulk, we rewrite the first law in a new form containing both $\Lambda$ (associated with thermodynamic pressure) and the central charge $C$ of the dual CFT theory and their...

In this talk I will report an analytic solution describing asymptotically anti–de Sitter black holes with hyperbolic horizon, derived in the context of f(R) generalizations to the Holst action, endowed with a dynamical Immirzi field. These black holes exhibit scalar hair of the second kind, which ultimately depends on the Immirzi field radial behavior. In particular, the latter is reponsible...

We show that the apparent horizon and the region near r=0 of an evaporating charged, rotating black hole are timelike. It then follows that for black holes in nature, which invariably have some rotation, have a channel, via which classical or quantum information can escape to the outside, while the black hole shrinks in size. We discuss implications for the information loss problem.

A method will be presented which allows for the numerical computation of the stress-energy tensor for a quantized massless minimally coupled scalar field in the region outside the event horizon of a 4D Schwarzschild black hole that forms from the collapse of a null shell. This method involves taking the difference between the stress-energy tensor for the $in$ state in the collapsing null shell...

The two-point function for a massless minimally coupled scalar field in the Unruh state is computed for various examples of 1+1 dimensional black holes. It is found that for spacelike separations of the points the two-point function grows linearly in terms of a time coordinate that is well-defined on the future black hole horizon, and for Schwarzschild-de Sitter black holes is also...

I review the arguments supporting the idea that there is an information puzzle in black holes physics. Namely that unitarity is conflicting with local quantum field theory and the equivalence principle. I show that these arguments rely on speculative extra assumptions, justified only by faith in specific hypothesis on quantum gravity. Therefore the black hole information puzzle a problem only...

This talk investigates thermodynamics, quasi-normal modes, thermal fluctuations and phase transitions of Reissner-Nordstrom black hole with the effects of non-linear electrodynamics. We first compute the expressions for Hawking temperature, entropy and heat capacity of this black hole and then obtain a relation between Davies point and quasi-normal modes with non-linear electrodynamics. We...

Since its inception, the Bekenstein-Hawking area relation for black-hole entropy has been the primary testing ground for various theories of quantum gravity. However, a key challenge to such theories is identifying the microscopic structures and explaining the exponential growth of microstates, providing a fundamental understanding of thermodynamic quantities. Since entropy is a single number,...

Einstein equations projected on Black Hole horizons give rise to the equations of motion of a viscous fluid. This suggests a way to understand the microscopic degrees of freedom on the Black Holehorizon by focusing on the physics of this fluid. In this talk, we shall approach this problem by building a crude microscopic model for the Horizon-fluid(HF) corresponding to asymptotically flat Black...

Hawking radiation remains a crucial theoretical prediction of semi-classical gravity and is considered one of the critical tests for a model of quantum gravity. However, Hawking’s original derivation used quantum field theory on a fixed background. Efforts have been made to include the space-time fluctuations arising from the quantization of the dynamical degrees of freedom of gravity itself...

We investigate radial Rindler trajectories in a Schwarzschild spacetime. We assume the trajectory to remain linearly uniformly accelerated (LUA) throughout its motion, in the sense of the curved spacetime generalisation of the Letaw-Frenet equations. For the Schwarzschild spacetime, we arrive at a bound on the magnitude of the acceleration $|a|$ for radially inward moving trajectories, in...

We describe an action principle, within the framework of the Eddington gravity, which incorporates the matter fields in a simple manner. Interestingly, the gravitational field equations derived from this action is identical to Einstein’s equations, in contrast with the earlier attempts in the literature. The cosmological constant arises as an integration constant in this approach. In fact, the...

We derive Smarr-type mass formulas for black holes solutions with non-connected horizons, represented by their rod structure, in the framework of the EMDA theory, generalizing the results of the recent paper “On the Smarr formulas for electrovac spacetimes with line singularities - ScienceDirect”. Our formalism covers such configurations as aligned multiple black holes joined by struts and...