Gravity and Cosmology

In this paper, we probe in 4D Einstein–Gauss–Bonnet black hole and its thermodynamics. We illustrate the three asymptotically 4D EGB spacetime as an asymptotically flat, de Sitter, and Anti-de Sitter. Also, we apply the tunneling of the massless particles from the horizon of 4D EGB gravity and we investigate the correlation between the emission modes and temperature of the horizon. In asymptotically flat spacetime, the existence of the coupling constant alone constructs the regular spacetime, the radiation deviates from the pure thermal, and the temperature of the black hole horizon would be zero in the final stage of the black hole evaporation. In Asymptotically de Sitter spacetime, results illustrate that the evolution of the temperatures is in direction of the remaining rest mass with the probably same temperature for the black hole and the cosmological horizon. In addition, the exciting result is that temperature behaviors exactly match with the temperature behaviors of a regula...

We study radiation of a quantum deformed Schwarzschild black hole surrounded by a quintessence field, through a tunneling process. When the background spacetime of a black hole is covered by a scalar field, such as a quintessence field, metric of the black hole changes for a particular range of the mass. Then, the geometry of the Schwarzschild black hole with one black hole horizon converts to geometry with two horizons: a black hole horizon and a cosmological horizon. In the presence of the quintessence as a background field, we study the tunneling process for massless and massive particles and we obtain the temperature of the black hole. We calculate and compare particles' tunneling rate from both of the black hole horizon and the cosmological horizon. The obtained temperature is regular, radiation modes encompass correlations and there is the Planck scale remnant with the quintessence contents. As an important result, thermodynamics of the Schwarzschild black hole surrounded by the quintessence field has a significant difference in the range − 2 3 < w q < − 1 3 relative to the ordinary case. Also, the behavior of temperatures in our case becomes similar to the Schwarzschild de-Sitter black hole temperatures. Furthermore, we show that quantum correction of the black hole in an embrace of the quintessence field changes the location of horizons but the quintessence field is more effective in this change. Eventually, while the quantum correction prevents to reach the singularity at r = 0 in the final stage of the evaporation of the quantum deformed Schwarzschild black hole surrounded by quintessence, there is a Planck scale remnant with quintessence content.

Inspired by string theory, Heisenberg's uncertainty principle can be generalized to include the photon-electron gravitational interaction, which leads to the Generalized Uncertainty Principle (GUP). Although GUP considers gravitational uncertainty at the minimum fundamental length scale in physics, it does not consider the effects of spacetime curvature on quantum mechanical uncertainty relations. The Extended Uncertainty Principle (EUP) is a generalization of Heisenberg's Uncertainty Principle that, unlike the GUP, applies to large length scales. GEUP is also a linear combination of EUP and GUP that creates minimal uncertainty on large length scales. The Einstein-Gauss-Bonnet theory (EGB) can be considered as one of the most promising candidates for modified gravity. In this paper, by using GUP, EUP, and GEUP, we intend to obtain the Hawking temperature of a four-dimensional EGB black hole in the asymptotically flat and (Anti)-de Sitter spacetime. We show that coupling constant, cosmological constant, mass, and radius significantly affect Hawking temperature and decrease or increase Hawking temperature depending on the chosen horizons.

Inspired by string theory, Heisenberg's uncertainty principle can be generalized to include the photon-electron gravitational interaction, which leads to the Generalized Uncertainty Principle (GUP). Although GUP considers gravitational uncertainty at the minimum fundamental length scale in physics, it does not consider the effects of spacetime curvature on quantum mechanical uncertainty relations. The Extended Uncertainty Principle (EUP) is a generalization of Heisenberg's Uncertainty Principle that, unlike the GUP, applies to large length scales. GEUP is also a linear combination of EUP and GUP that creates minimal uncertainty on large length scales. The Einstein-Gauss-Bonnet theory (EGB) can be considered as one of the most promising candidates for modified gravity. In this paper, by using GUP, EUP, and GEUP, we intend to obtain the Hawking temperature of a four-dimensional EGB black hole in the asymptotically flat and (Anti)-de Sitter spacetime. We show that coupling constant, cosmological constant, mass, and radius significantly affect Hawking temperature and decrease or increase Hawking temperature depending on the chosen horizons.

In this paper, we probe in 4D Einstein-Gauss-Bonnet black hole and its thermodynamics. We illustrate the three asymptotically 4D EGB spacetime as an asymptotically flat, de Sitter, and Anti-de Sitter. Also, we apply the tunneling of the massless particles from the horizon of 4D EGB gravity and we investigate the correlation between the emission modes and temperature of the horizon. In asymptotically flat spacetime, the existence of the coupling constant alone constructs the regular spacetime, the radiation deviates from the pure thermal, and the temperature of the black hole horizon would be zero in the final stage of the black hole evaporation. In Asymptotically de Sitter spacetime, results illustrate that the evolution of the temperatures is in direction of the remaining rest mass with the probably same temperature for the black hole and the cosmological horizon. In addition, the exciting result is that temperature behaviors exactly match with the temperature behaviors of a regular black hole in Lovelock gravity in a higher dimension.

We study radiation of a quantum deformed Schwarzschild black hole surrounded by a quintessence field, through a tunneling process. When the background spacetime of a black hole is covered by a scalar field, such as a quintessence field, metric of the black hole changes for a particular range of the mass. Then, the geometry of the Schwarzschild black hole with one black hole horizon converts to geometry with two horizons: a black hole horizon and a cosmological horizon. In the presence of the quintessence as a background field, we study the tunneling process for massless and massive particles and we obtain the temperature of the black hole. We calculate and compare particles' tunneling rate from both of the black hole horizon and the cosmological horizon. The obtained temperature is regular, radiation modes encompass correlations and there is the Planck scale remnant with the quintessence contents. As an important result, thermodynamics of the Schwarzschild black hole surrounded by the quintessence field has a significant difference in the range − 2 3 < w q < − 1 3 relative to the ordinary case. Also, the behavior of temperatures in our case becomes similar to the Schwarzschild de-Sitter black hole temperatures. Furthermore, we show that quantum correction of the black hole in an embrace of the quintessence field changes the location of horizons but the quintessence field is more effective in this change. Eventually, while the quantum correction prevents to reach the singularity at r = 0 in the final stage of the evaporation of the quantum deformed Schwarzschild black hole surrounded by quintessence, there is a Planck scale remnant with quintessence content.

We study cosmological Lemaitre-Tolman-Bondi (LTB) black hole thermodynamics immersed in a quintom universe. We investigate some thermodynamic aspects of such a black hole in detail. We apply two methods of treating particles' tunneling from the apparent horizons and calculate the black hole's temperature in each method; the results of which are the same. In addition, by considering specific time slices in the cosmic history, we study the thermodynamic features of this black hole in these specific cosmic epochs. Also, we discuss the information loss problem and the remnant content of the cosmological black hole in different cosmic epochs in this context. We show that approximately in all the cosmic history, the temperature of the black hole's apparent horizon is more than the temperature of the cosmological apparent horizon.

We study cosmological Lemaitre-Tolman-Bondi (LTB) black hole thermodynamics immersed in a quintom universe. We investigate some thermodynamic aspects of such a black hole in detail. We apply two methods of treating particles' tunneling from the apparent horizons and calculate the black hole's temperature in each method; the results of which are the same. In addition, by considering specific time slices in the cosmic history, we study the thermodynamic features of this black hole in these specific cosmic epochs. Also, we discuss the information loss problem and the remnant content of the cosmological black hole in different cosmic epochs in this context. We show that approximately in all the cosmic history, the temperature of the black hole's apparent horizon is more than the temperature of the cosmological apparent horizon.