arXiv subjects

Behnam Pourhassan

Publications and source records attributed to Behnam Pourhassan.

At least 73 records · Page 4Linked to original sources

arXiv2022

Quantum Thermodynamics of an $α^{\prime}$-Corrected Reissner-Nordström Black Hole

In this paper, we will analyze the effects of $α^{\prime} $ corrections on the behavior of a Reissner-Nordström black hole. We will calculate the effects of such corrections on the thermodynamics and thermodynamic stability of such a black hole. We will also derived a novel $α^{\prime}$-corrected first law. We will investigate the effect of such corrections on the Parikh-Wilczek formalism. This will be done using cross entropy and Kullback-Leibler divergence between the original probability distribution and the $α^{\prime}$-corrected probability distribution. We will then analyze the non-equilibrium quantum thermodynamics of this black hole. It will be observed that its quantum thermodynamics is corrected due to quantum gravitational corrections. We will use Ramsey scheme for emitted particles to calculate the quantum work distribution for this system. The average quantum work will be related to the difference of $α^{\prime}$-corrected free energies using the Jarzynski equality.

hep-th↗

arXiv2022

Non-perturbative correction to the Horava-Lifshitz black hole thermodynamics

In this paper, we consider non-perturbative quantum correction which appears as exponential term in the black hole entropy. We study consequence thermodynamics of the Hořava-Lifshitz black hole at quantum scales. We consider two cases of Kehagius-Sfetsos and Lu-Mei-Pop solutions and investigate black hole stability. We find that non-perturbative quantum correction yields to an instability at infinitesimal horizon radius of Kehagius-Sfetsos solution. On the other hand, non-perturbative quantum correction yields to the stability of Lu-Mei-Pop solution. Hence, we find that holographic dual of Lu-Mei-Pop black hole (in absence of non-perturbative quantum correction) is the interacting gas of point like particles, while it is Van der Waals fluid in presence of non-perturbative quantum correction.

hep-th↗

arXiv2022

Weak Gravity Conjecture of Charged-Rotating-AdS Black Hole Surrounded by Quintessence and String Cloud

A series of corrections to general relativity have recently been applied to find the relationship between entropy and extremality-bound black holes. This relationship has been investigated for many black holes, such as charged AdS, rotating, and massive gravity black holes. We give a minor constant correction to the action and confirm these universal relations for a charged-rotating-AdS black hole. We then examine these calculations for the black hole, surrounded by the quintessence and the cloud of string. In this paper, we evaluate a new universal relation. It means that we find the relation between the extremal mass of the black hole and the factor of cloud string and observe that the corresponding universal relation is well established. We find that the quintessence terms play a very effective role in calculating the mass-charge ratio and concept of weak gravity conjecture of black holes. We note here that the added constant correction is inversely related to the entropy of the black hole. It leads us to see that the mass-to-charge ratio decreases and fully confirms the black hole's weak gravity conjecture (WGC).

gr-qc↗

arXiv2022

Quantum Thermodynamics of a Quantum Sized AdS Black Hole

In this paper, we investigate the effects of non-perturbative quantum gravitational corrections on a quantum sized AdS black hole. It will be observed that these non-perturbative quantum gravitational corrections modify the stability of this black hole. We will use the non-equilibrium quantum thermodynamics to investigate the evaporation of this black hole between two states. We will analyze the effects of non-perturbative quantum gravitational corrections on this non-equilibrium quantum thermodynamics. We will explicitly obtain the quantum work distribution for this black hole, as it evaporates between two states. It will be observed that this quantum work distribution is modified due to non-perturbative quantum gravitational corrections.

gr-qc↗

arXiv2022

Modified Cosmic Chaplygin AdS Black Hole

In this paper, we construct a new charged AdS black hole with modified cosmic Chaplygin gas (MCCG). In comparison to the previous model (modified Chaplygin AdS black hole) existed in the literature, we now have two new parameters: the cosmic parameter and the black hole's electric charge. We examine the asymptotically charged AdS black hole thermodynamics with MCCG under the assumption of a negative cosmological constant as a thermodynamics pressure. Using MCCG, we developed a new solution to Einstein's AdS black hole field equations.The mass parameter, volume, electric potential, entropy, and temperature of the charged AdS black hole have all been computed. We also study the various energy conditions for the MCCG as a source fluid of AdS black hole. For some restrictions on the involved parameters, we show that these conditions are met. Then, we study the thermodynamical stability, critical points, and Joule-Thompson expansion for the back hole obtained. We reveal that while the existence of cosmic parameter yields to a complete stable mode, its absence gives rise to some unstable regions. Then, using MCCG, we treat the obtained black hole's thermodynamics as a heat engine and calculate the work done as well as the heat engine's maximum efficiency in the Carnot cycle. The work done, the efficiency, and the Rankine cycle's efficiency are also investigated. All of the findings are graphically depicted and discussed.

gr-qc↗

arXiv2022

Quantum Thermodynamics of an M2-M5 Brane System

We will investigate a system of M2-M5 branes as a black M2-M5 bound state. The behavior of this system will be investigated at short distances. At such scales, we will have to incorporate quantum gravitational corrections to the supergravity solutions. We will study the non-equilibrium quantum thermodynamics of this black M2-M5 bound state. The quantum work for this solution will be obtained using the Jarzynski equality. We will also study the corrections to the thermodynamic stability of this system from quantum gravitational corrections. We will use the concept of a novel quantum mass to analyze the quantum gravitational corrections to the information geometry of this system. This will be done using effective quantum metrics for this system.

hep-th↗

arXiv2022

Resolving the information loss paradox from the five-dimensional minimal supergravity black hole

In this paper, we study the Hawking tunneling radiation of the charged rotating black hole in five-dimensional minimal supergravity theory by using the semiclassical Hamilton-Jacobi equation. By using two separated ways we obtain the corrected entropy of the black hole. Equality of results gives us a special condition that may solve the information loss paradox. Then, we focus on the phase transitions, and the results show that if the effects of thermal fluctuations are incorporated in the entropy, the black hole is unstable, while there are phase transitions according to the sign-changing behavior of the black hole specific heat. We find that, in presence of thermal fluctuations, the black holes of five-dimensional minimal supergravity behave like the black holes in Horava-Lifshitz gravity hence the second-order phase transition is possible.

hep-th↗

arXiv2021

A Quantum Informational Approach to the Problem of Time

Several novel approaches have been proposed to resolve the problem of time by relating it to change. We argue using quantum information theory that the Hamiltonian constraint in quantum gravity cannot probe change, so it cannot be used to obtain a meaningful notion of time. This is due to the absence of quantum Fisher information with respect to the quantum Hamiltonian of a time-reparametization invariant system. We also observe that the inability of this Hamiltonian to probe change can be related to its inability to discriminate between states of such a system. However, if the time-reparametization symmetry is spontaneously broken due to the formation of quantum cosmological time crystals, these problems can be resolved, and it is possible for time to emerge in quantum gravity.

gr-qc↗

arXiv2021

Quantum Work and Information Geometry of a Quantum Myers-Perry Black Hole

In this paper, we will obtain quantum work for a quantum scale five dimensional Myers-Perry black hole. Unlike heat represented by Hawking radiation, the quantum work is represented by a unitary information preserving process, and becomes important for black holes only at small quantum scales. It will be observed that at such short distances, the quantum work will be corrected by non-perturbative quantum gravitational corrections. We will use the Jarzynski equality to obtain this quantum work modified by non-perturbative quantum gravitational corrections. These non-perturbative corrections will also modify the stability of a quantum Myers-Perry black hole. We will define a quantum corrected information geometry by incorporating the non-perturbative quantum corrections in the information geometry of a Myers-Perry black hole. We will use several different quantum corrected effective information metrics to analyze the stability of a quantum Myers-Perry black hole.

hep-th↗

arXiv2021

Quantum Corrections to the Thermodynamics of Black Branes

In this paper we study the thermodynamics of black branes at quantum scales. We analyze both perturbative and non-perturbative corrections to the thermodynamics of such black branes. It will be observed that these corrections will modify the relation between the entropy and area of these black branes. This will in turn modify their specific heat, and thus their stability. So, such corrections can have important consequences for the stability of black branes at quantum scales. We also analyze the effect of these perturbative and non-perturbative quantum corrections on various other thermodynamic quantities. Then, we obtain the metric for the quantum corrected geometry for black branes.

hep-th↗

arXiv2021

The large scale structure formation in an expanding universe

In this paper, we analyze the effects of expansion on large scale structure formation in our Universe. We do that by incorporating a cosmological constant term in the gravitational partition function. This gravitational partition function with a cosmological constant is used for analyzing the thermodynamics of this system. We analyze the virial expansion for this system, and obtain its equation of state. It is observed that the generalization of this equation of state is like the Van der Waals equation. We also analyze a gravitational phase transition in this system using the mean field theory. We construct the cosmic energy equation for this system of galaxies, and discuss its consequences. We obtain and analyze the distribution function for this system, using the gravitational partition function. We also compare the results obtained in this paper with the observational data.

physics.gen-ph↗

arXiv2021

Thermodynamics of the apparent horizon in the generalized energy-momentum-squared cosmology

In this note, we explore the thermodynamic properties of the universe in the background of the generalized energy-momentum-squared gravity. We derive the energy density of matter from the non-standard continuity equation and use it in our analysis. We consider two types of models depending on the nature of coupling between curvature and matter and perform thermodynamic analysis on them using the cosmic apparent horizon. The models are kept as generic as possible from the mathematical point of view in order to gain a wide applicability of the work. In this work we have considered power law and exponential form of models. All the thermodynamic parameters are expressed in terms of the cosmic apparent horizon radius and its time derivatives and their time evolution are studied. By using temperature, heat capacity analysis and the evolution trend of Helmholtz free energy the conditions for thermodynamic stability of the models are derived. It is seen that our stability analysis considerably constrain the parameter space of the model.

gr-qc↗

arXiv2021

Exponential corrected thermodynamics of black holes

Recently, it is reported that thermal fluctuations, which are interpreted as quantum effects, modify the black holes entropy by an exponential term. We now find the effect of such modification on the black hole mass and other thermodynamics quantities. We find that the Schwarzschild black hole mass decreased by thermal fluctuations. Hence, we study exponential corrected thermodynamics and statistics of black holes by computing the partition function. We obtain the special condition on the event horizon radius to satisfy Smarr-Gibbs-Duhem relation in the presence of quantum correction. As we know, the Schwarzschild black hole is unstable, while the effect of exponential correction is the stability of $4D$ Schwarzschild black hole as well as the Schwarzschild-AdS black hole at a small area. On the other hand, a $5D$ Schwarzschild black hole is completely unstable. The effect of the quantum correction on the Reissner-Nordström black hole is instability at quantum scales. Finally, we consider the most general case of charged AdS black hole and study the corrected thermodynamics.

gr-qc↗

arXiv2021

Logarithmic corrections to Newtonian gravity and Large Scale Structure

Effects from nonstandard corrections to Newtonian gravity, at large scale, can be investigated using the cosmological structure formation. In particular, it is possible to show if and how a logarithmic correction (as that induced from nonlocal gravity) modifies the clustering properties of galaxies and of clusters of galaxies. The thermodynamics of such systems can be used to obtain important information about the effects of such modification on clustering. We will compare its effects with observational data and it will be demonstrated that the observations seem to point to a characteristic scale where such a logarithmic correction might be in play at galactic scales. However, at larger scales such statistical inferences are much weaker, so that a fully reliable statistical evidence for this kind of corrections cannot be stated without further investigations and the use of more varied and precise cosmological and astrophysical probes.

gr-qc↗

arXiv2021

Finite Tsallis Gravitational Partition Function for a System of Galaxies

In this paper, we will study the large scale structure formation using the gravitational partition function. We will assertively argue that the system of gravitating galaxies can be analyzed using the Tsallis statistical mechanics. The divergences in the Tsallis gravitational partition function can be removed using the mathematical riches of the generalization of the dimensional regularization (GDR). The finite gravitational partition function thus obtained will be used to evaluate the thermodynamics of the system of galaxies and thus, to understand the clustering of galaxies in the universe. The correlation function which is believed to contain the information of clustering of galaxies will also be discussed in this formalism.

gr-qc↗

arXiv2021

Note on the thermodynamic stability of a black ring at quantum scales

In this paper, the thermodynamic properties of a thin black ring in AdS space-time is explored when the size of the ring is comparable to quantum scales. The angular momentum to mass ratio of this system has an upper limit, which is the cosmological radius of the black ring. It is found that the small black ring will be thermodynamically stable due to the effects introduced by thermal fluctuations. However, we find that the black ring is less stable than thermal AdS. Thermodynamic analysis indicates that there is no critical point, but there is Hawking-Page transition to radiation, which is confirmed by the Gibbs free energy analysis.

gr-qc↗

arXiv2021

Perturbed thermodynamics of charged black hole solution in Rastall theory

We study the thermodynamics of a charged black hole surrounded by a perfect fluid in Rastall theory and investigate three different cases of quintessence, dust and radiation fields. By considering thermal fluctuations, we study the corrected thermodynamics of the system. We investigate the effects of thermal fluctuations on the black hole stability, phase transition and critical points. We show that the thermal fluctuations increase instability of the black hole and may yield to the second order phase transition. We also compare our result with uncharged cases to find the effects of the black hole charge on the thermodynamics quantities. We find that large black holes behave like a Van der Waals fluid, while for the small black hole where thermal fluctuations become important, there is no Van der Waals behaviour. Finally, we briefly discuss about geometric thermodynamics to obtain corrected scalar curvature.

gr-qc↗

arXiv2021

Non-Pertubative Quantum Corrections to a Born-Infeld Black Hole and its Information Geometry

We study the non-perturbative quantum corrections to a Born-Infeld black hole in a spherical cavity. These quantum corrections produce a non-trivial short distances modification to the relation between the entropy and area of this black hole. The non-perturbative quantum correction appears as an exponential term in the black hole entropy. This in turn modifies the thermodynamics of a given system, for example reduced value of the Helmholtz free energy. Moreover, the first law of black hole thermodynamics modified due to quantum corrections. We also investigate the effect of such non-perturbative corrections on the information geometry of this system. This is done using some famous information metrics.

gr-qc↗