Narrow Results

We study (3+1) Morris–Thorne wormhole to investigate its thermodynamic properties. It is shown that the wormhole temperature can be evaluated by exploiting Unruh effects. We also propose a possibility of negative temperature originated from exotic matter distribution of the wormhole.

Recent research on Hawking radiations of the Rindler spacetime and spherically symmetric uncharged spacetime shows that the Hawking temperature can be obtained by fermions tunnelling method. In this paper, we extend this work to the charged rotating spacetime and review the Hawking radiation of the Kerr–Sen dilaton–axion black hole by fermions tunnelling. The Hawking temperature is recovered and is exactly the same as that obtained by other methods.

We consider a freely falling holographic screen for the Schwarzschild and Reissner–Nordström black holes and evaluate the entropic force à la Verlinde. When the screen crosses the event horizon, the temperature of the screen agrees to the Hawking temperature and the entropic force gives rise to the surface gravity for both of the black holes.

We established the equivalence between the local Hawking temperature measured by the time-like Killing observer located at some positions r with finite distances from the outer horizon r₊ in the five-dimensional spinning black hole space with both negative and positive constant curvature, and the Unruh temperature measured by the Rindler observer with constant acceleration in the six-dimensional flat space by employing the globally embedding approach.

In this paper, we calculate the heat flux passing through the horizon TS|_rh and the difference of energy between the Einstein and Møller prescription within the region , in which is the region between outer horizon and inner horizon , for the modified GHS solution, KLOPP solution and CLH solution. The formula TS is obeyed for the mGHS solution and the KLOPP solution, but not for the CLH solution. Also, we suggest a RN-like stringy dyonic black hole solution, which comes from the KLOPP solution under a dual transformation, and its thermodynamical properties are the same as the KLOPP solution.

In this work we have studied the scattering of scalar field around an extended black hole in F(R) gravity using WKB method. We have obtained the wave function in different regions such as near the horizon region, away from horizon and far away from horizon and the absorption cross-section are calculated. We find that the absorption cross-section is inversely proportional to the cube of Hawking temperature. We have also evaluated the Hawking temperature of the black hole via tunneling method.

We calculate the heat transfer passing through two horizons of charged dilaton–axion black hole and the quasi-localized energy in the patch ℳ between two horizons. The result E_Einstein|_ℳ = E _Møller|_ℳ-∑_∂ℳTS is a Legendre transformation. So that the quasi-localized energy E_Einstein and E_Møller in the patch ℳ could be considered as thermodynamic potentials.

The radiation of vector particles by black holes in (1+2) dimensions is investigated within the WKB approximation. We consider the process of quantum tunneling of bosons through an event horizon of the black hole. The emission temperature for the Schwarzschild background geometry coincides with the Hawking temperature and for the Rindler spacetime the temperature is the Unruh temperature. We also obtain the radiation temperature for the de Sitter spacetime.

Adopting the Hamilton–Jacobi method, we investigated the tunneling radiation of a deform Hořava–Lifshitz black hole, and the original tunneling rate and Hawking temperature are obtained. Based on the generalized uncertainty principle, recent researches imply that the quantum gravity corrected the Dirac equation exactly. Hence, the corrected Dirac equation can express the tunneling behavior of fermions may be more suitable, and meanwhile, the corrected Hawking temperature of the Hořava–Lifshitz black hole is obtained. Comparing with previous results, we find that the Hawking temperature is not only related to the mass of black hole, but also related to the mass and energy of outgoing fermions. Finally, we inferred that the Hawking radiation would stop by the reason of the quantum gravity, and the remnant of the black hole exists naturally, also the singularity of the black hole is avoided.

Using a single particle density distribution for the self-gravitating quantum particles that form an interacting N-particle system which ultimately forms a black hole, we from a condensed matter point of view derive the expressions of the Schwarzschild radius and the Hawking temperature. Including the quantum mechanical exchange correlation energy for the particles, we find small corrections to the above two physical quantities. The approximate expression of ground state energy and the numerical coefficient of the formula for Hawking temperature provide the hint to enable us to propose an exact expression for the ground state energy of the system.

According to the dispersion relation that stems from the string theory and the quantum gravitational theory, we study the dynamic equation of fermions, that is Rarita–Schwinger equation. Based on the Lorentz dispersion relation modified in the high-energy case, the dynamic equation of arbitrary spin fermions is accurately corrected in the Kerr Anti-de Sitter black hole, then the action of fermions with arbitrary spin is computed. To do so, we obtain the new expressions for tunneling rate, Hawking temperature and entropy of the black hole. At last, some comments are made on the results of our work.

The expressions for the corrected radius and the Hawking temperature of a Schwarzschild black hole are derived by calculating the total energy of a self-gravitating system of N fermions when the corrections to gravitational interaction due to post-Newtonian-like self-energy due to two graviton exchange- and one-loop contribution of quantum gravity effect are included. Since the particles are fermions, the exchange-correlation energy is also included consistently. It is found that though the three corrections are small, the correction due to the exchange-correlation is much more than the other two. The configuration of the many-particle system that we study is possible since it has no Buchdahl limit in the post-Newtonian approximation.

In this work, we study the RVB method for calculating the Hawking temperature of different black holes and find that there is an undetermined integral constant in the temperature expression. We use this method to calculate the Hawking temperature of the black hole in Einstein gravity, and massive gravity, Einstein–Gauss–Bonnet gravity, Scalar–Tensor–Vector modified gravity and $f(R)$ gravity, respectively. By comparing with the temperature obtained by the Hawking temperature formula, we find that regardless of the gravitational theory from which the black hole solution is obtained, after the black hole metric is reduced to two dimensions, if there is no first-order term of $r$ in $g_{00}$, the integral constant is 0. If there is a first-order term of $r$ in $g_{00}$, the integral constant is determined by the coefficient in front of the first-order term of $r$.

For black holes with more than one horizon, the existence of a global temperature is not fully understood. This can affect the thermodynamics of these black holes to be unclear. In this paper, using the method of quantum tunneling, we find a global temperature for asymptotically AdS multi-horizon black holes appeared in three-dimensional quasitopological gravities given by $T_H={\kappa }_{\mathrm{\text{eff}}}/2\pi$, in which the effective surface gravity is related to the surface gravity of each horizon. We also find a global temperature for the asymptotically warped AdS₃ black holes, having the same expression as the AdS multi-horizon black holes. In all of the cases the global temperature differs from the conventional Hawking temperature.

We investigate the radiation of spin-1 particles by black holes in (1+1) dimensions within the Proca equation. The process is considered as quantum tunneling of bosons through an event horizon. It is shown that the emission temperature for the Schwarzschild background geometry is the same as the Hawking temperature corresponding to scalar particles emission. We also obtain the radiation temperatures for the de Sitter, Rindler and Schwarzschild–de Sitter space–times. In a particular case when two horizons in Schwarzschild–de Sitter space–time coincides, the Nariai temperature is recovered. The thermodynamical entropy of a black hole is calculated for Schwarzschild–de Sitter space–time having two horizons.

We study the cascade of Hawking emission spectrum from the event horizon in the presence of one loop backreaction effect in a black hole background. The space–time taken here is the modified Schwarzschild one. The analysis shows that it is possible to decrease the sparsity with the decrease in black hole mass. Moreover, at some particular value of mass, one has a continuous radiation cascade. This result is completely new and quite different from the usual one. An estimation of the mass for continuous one is also found. We see that the value is of the Planck mass order. In this process, it is observed that under a physical background, below a particular value of the mass, the Hawking radiation must stop and we have a remnant. This was absent in the earlier analysis.

Motivated by the study of soluble models of quantum field theory, we illustrate a new type of topological effect by comparing the constructions of canonical Klein–Gordon quantum fields on the two-dimensional de Sitter spacetime as opposed to its double covering. We show that while the commutators of the two fields coincide locally, the global topological differences make the theories drastically different. Many of the well-known features of de Sitter quantum field theory disappear. In particular, there is nothing like a Bunch–Davies vacuum. Correspondingly, even though the local horizon structure is the same for the two universes, there is no Hawking–Gibbons thermal state. Finally, there is no complementary series of fields.

The motivation behind this study is to enumerate the leading order corrections to the thermodynamics of BTZ black hole (named after three scientists; Banados, Teitelboim, and Zanelli). We first analyze the effect of quantum corrections (motivated from string theory and loop quantum gravity) on various thermodynamic variables for uncharged and stationary BTZ black hole. We, later on, endow charges and rotations to the same black hole and rederive all the expressions once again. The comparative analysis is done between the corrected and uncorrected thermodynamics via plots.

Our aim, in this paper, is to study the generalized second law by considering the dynamical apparent horizon to be endowed with the Hawking temperature and the Viaggiu entropy introduced in a pioneering work in 2014. We have devoted our attention to a flat FLRW universe filled with a perfect fluid having a constant equation of state $p=w\rho$. It is worthwhile to note that we have considered both forms of the Hawking temperature, the original one as well as the truncated version. The latter one is generally used during calculations, however, several arguments have been put forward against it. Our analysis yields a startling result. The Viaggiu entropy naturally forbids the phantom era. In other words, the Viaggiu entropy will never allow the EoS parameter to go beyond the Cosmological Constant. This result is in strong agreement with recent observations and we have deduced it purely by thermodynamic means. This is in striking contrast with the results obtained with the Bekenstein–Hawking formalism.

We explore the interplay between quantization, local commutativity and the analyticity properties of the two-point functions of a quantum field in a non trivial topological cosmological background in the example of the two-dimensional de Sitter manifold and its double covering. The global topological differences make the many of the well-known features of de Sitter quantum field theory disappear. In particular there is nothing like a Bunch-Davies vacuum and there are no $SL(2,R)$-invariant fields whose mass is less than 1/2.