Generalized Tortoise Coordinate Transformation Research Articles

Tunneling radiation of fermions with 1/2 and 3/2 spins from a charged axisymmetric nonstationary black hole

In this paper, we derived Hamilton–Jacobi equation for spin 1/2 and 3/2 fermions from Dirac equation and Rarita–Schwinger equation. Then, by using the Hamilton–Jacobi equation and general tortoise coordinate transformation, the tunneling rate and Hawking temperatures of a nonstationary axisymmetric symmetry black hole are investigated. The result shows that the tunneling rate, temperature and surface gravity are all related to the properties of horizons of the black hole, the cosmological constant [Formula: see text], the charge [Formula: see text], mass of black hole [Formula: see text] and the Eddington time [Formula: see text].

Quantum Radiation Properties of General Nonstationary Black Hole

Using the generalized tortoise coordinate transformations the quantum radiation properties of Klein-Gordon scalar particles, Maxwell’s electromagnetic field equations, and Dirac equations are investigated in general nonstationary black hole. The locations of the event horizon and the Hawking temperature depend on both time and angles. A new extra coupling effect is observed in the thermal radiation spectrum of Maxwell’s equations and Dirac equations which is absent in the thermal radiation spectrum of scalar particles. We also observe that the chemical potential derived from scalar particles is equal to the highest energy of the negative-energy state of the scalar particle in the nonthermal radiation in general nonstationary black hole. Applying generalized tortoise coordinate transformation a constant termξis produced in the expression of thermal radiation in general nonstationary black hole. It indicates that generalized tortoise coordinate transformation is more accurate and reliable in the study of thermal radiation of black hole.

Hawking Radiation via Damour-Ruffini Method in Squashed Charged Rotating Kaluza-Klein Black Holes

Using the Damour-Ruffini method, Hawking radiation of charged particles from squashed charged rotating five-dimensional Kaluza-Klein black holes is investigated extensively. Under the generalized tortoise coordinate transformation, Hawking temperature of the black holes is calculated by using charged scalar particles and Dirac fermions respectively. We find that the obtained Hawking temperature for charged Dirac fermions is the same as for charged scalar particles. What’s more, the spectrum of Hawking radiation contains the information of the size of the extra dimension, which could provide insight for further investigation of large extra dimensions in the future.

Quantum radiation of Maxwell’s electromagnetic field in nonstationary Kerr–de Sitter black hole

Quantum radiation properties of nonstationary Kerr–de Sitter (KdS) black hole is investigated using the method of generalized tortoise coordinate transformation. The locations of horizons and the temperature of the thermal radiation as well as the maximum energy of the nonthermal radiation are derived. It is found that the surface gravity and the Hawking temperature depend on both time and different angles. An extra coupling effect is obtained in the thermal radiation spectrum of Maxwell’s electromagnetic field equations which is absent in the thermal radiation spectrum of scalar particles. Further, the chemical potential derived from the thermal radiation spectrum of scalar particle has been found to be equal to the highest energy of the negative energy state of the scalar particle in the nonthermal radiation for KdS black hole. It is also shown that the generalized tortoise coordinate transformation produces a constant term in the expression of the surface gravity and Hawking temperature.

Hawking radiation of stationary and non-stationary Kerr–de Sitter black holes

Hawking radiation of the stationary Kerr–de Sitter black hole is investigated using the relativistic Hamilton–Jacobi method. Meanwhile, extending this work to a non-stationary black hole using Dirac equations and generalized tortoise coordinate transformation, we derived the locations, the temperature of the thermal radiation as well as the maximum energy of the non-thermal radiation. It is found that the surface gravity and the Hawking temperature depend on both time and different angles. An extra coupling effect is obtained in the thermal radiation spectrum of Dirac particles which is absent from thermal radiation of scalar particles. Further, the chemical potential derived from the thermal radiation spectrum of scalar particle has been found to be equal to the highest energy of the negative energy state of the scalar particle in the non-thermal radiation for the Kerr–de Sitter black hole. It is also shown that for stationary black hole space time, these two different methods give the same Hawking radiation temperature.

A New General Tortoise Coordinate Transformation and Quantum Tunneling Effect of the Non-Stationary Higher Dimensional Vaidya-de Sitter Black Hole

In this paper, we combine the Hamilton-Jacobi equation with a new general tortoise coordinate transformation to study quantum tunneling of scalar particles and fermions from the non-stationary higher dimensional Vaidya-de Sitter black hole. The results show that Hamilton-Jacobi equation is a semi-classical foundation equation which can easily derived from the particles’ dynamic equations, it can helps us understand the origin of Hawking radiation. Besides, based on the dimensional analysis, we believed that the new general tortoise coordinate transformation is more reasonable than old ones.

Quantum Radiation Properties of Dirac Particles in General Nonstationary Black Holes

Quantum radiation properties of Dirac particles in general nonstationary black holes in the general case are investigated by both using the method of generalized tortoise coordinate transformation and considering simultaneously the asymptotic behaviors of the first-order and second-order forms of Dirac equation near the event horizon. It is generally shown that the temperature and the shape of the event horizon of this kind of black holes depend on both the time and different angles. Further, we give a general expression of the new extra coupling effect in thermal radiation spectrum of Dirac particles which is absent from the thermal radiation spectrum of scalar particles. Also, we reveal a relationship that is ignored before between thermal radiation and nonthermal radiation in the case of scalar particles, which is that the chemical potential in thermal radiation spectrum is equal to the highest energy of the negative energy state of scalar particles in nonthermal radiation for general nonstationary black holes.

New tortoise coordinate transformation and Hawking’s radiation in de Sitter space

Hawking’s radiation effect of Klein-Gordon equation, Dirac particles and Maxwell’s electromagnetic fields in the non-stationary rotating de Sitter cosmological space-time is investigated by using a new method of generalized tortoise coordinate transformation. It is found that the new transformation produces constant additional terms in the expressions of the surface gravities and the Hawking’s temperatures. If the constant terms are set to zero, then the surface gravities and Hawking’s temperatures will be equal to those obtained from the old generalized tortoise coordinate transformations. This shows that the new transformations are more reasonable. The Fermionic spectrum of Dirac particles displays a new spin-rotation coupling effect.

Quantum Tunneling of the Non-stationary Kerr-Newman Black Hole via a New Type of General Tortoise Coordinate Transformation

In this paper, the quantum tunneling of the non-stationary Kerr-Newman black hole is investigated via Hamilton-Jacobi equation and two types of general tortoise coordinate transformations. The tunneling rates, the Hawking temperatures and radiation spectrums are derived respectively. Our result shows that the new type of general tortoise coordinate transformation is more reasonable.

Hawking radiation from a dynamical Kerr–Newman black hole

After Hawking radiation from a Schwarzschild black hole is calculated using the Damour–Ruffini method, the tortoise coordinate transformation in a static black hole is extended to a dynamical axisymmetric black hole, such as a dynamical Kerr–Newman black hole. Under the generalized tortoise coordinate transformation, Hawking radiation from a dynamical Kerr–Newman black hole is obtained successfully. Moreover, it also seems to occur on the apparent horizon instead of the event horizon.

Fermions Tunneling from Non-Stationary Dilaton–Maxwell Black Hole via General Tortoise Coordinate Transformation

Fermions tunneling of the non-stationary Dilaton–Maxwell black hole is investigated with general tortoise coordinate transformation. The Dirac equation is simplified by semiclassical approximation so that the Hamilton–Jacobi equation is generated. Finally the tunneling rate and the Hawking temperature is calculated.

FERMIONS TUNNELING FROM BARDEEN–VAIDYA BLACK HOLE VIA GENERAL TORTOISE COORDINATE TRANSFORMATION

In this paper, we research on the scalar field particles and 1/2 spin fermions tunneling from the event horizon of Bardeen–Vaidya black hole by semiclassical method and general tortoise coordinate transformation, and obtain the Hawking temperature and tunneling rate near the event horizon.

A new method of researching fermion tunneling from the Vaidya–Bonner de Sitter black hole

Using the general tortoise coordinate transformation, we research the fermion tunneling of the Vaidya–Bonner de Sitter black hole via a semi-classical method and finally obtain the right surface gravity, Hawking temperature and tunneling rate near the event horizon and cosmical horizon.

CHARACTERISTICS OF QUANTUM RADIATION OF SLOWLY VARYING NONSTATIONARY KERR–NEWMAN BLACK HOLES

Quantum radiative characteristics of slowly varying nonstationary Kerr–Newman black holes are investigated by using the method of generalized tortoise coordinate transformation. It is shown that the temperature and the shape of the event horizon of this kind of black holes depend on the time and the angle. Further, we reveal a previously ignored relationship between thermal radiation and nonthermal radiation, which is that the chemical potential in the thermal radiation spectrum is equal to the highest energy of the negative energy state of particles in nonthermal radiation for slowly varying nonstationary Kerr–Newman black holes. Also, we show that the deduced general results can be degenerated to the known conclusion of stationary Kerr–Newman black holes.

Further discussion on the entropy of Dirac field in spherically symmetric non-static black hole

A new general tortoise coordinate transformation is used with the thin film brick-wall model.We further discuss the Hawking temperature and the entropy of Dirac field in spherically symmetric non-static black hole.The cut-off parameter does not vary for different time-space structure,and it is reduced to that of the stationary cases.

Quasinormal modes in a time-dependent black hole background

We have studied the evolution of the massless scalar field propagating in a time-dependent charged Vaidya black hole background. A generalized tortoise coordinate transformation was used to study the evolution of the massless scalar field. It is shown that, for the slowest damped quasinormal modes, the approximate formulas in the stationary Reissner-Nordstr\"om black hole turn out to be a reasonable prescription, showing that results from quasinormal mode analysis are rather robust.

Hawking Radiation of Dirac Particles in a Nonuniformly Rectilinearly Accelerating Black Hole

The Hawking radiation of Dirac particles on the event horizon of a nonuniformly rectilinearly accelerating black hole is studied in this paper. First, we construct the symmetrized null tetrad from which the spin coefficients and Dirac equation are derived. Next, by proposing generalized tortoise coordinate transformation, the decoupling problem of the Dirac equation with nonzero rest mass is solved. Finally, by analytic continuation, the Hawking thermal spectrum formula of Dirac particle for nonuniformly rectilinearly accelerating black hole is obtained.

Hawking radiation of Dirac particles in a nonuniformly rectilinearly acceleratin g black hole with electric and magnetic charge

The Hawking radiation of Dirac particles on event horizon of nonuniformly rectilinearly accelerating black hole with electric and magnetic charge is studied in this paper. First, we construct the symmetrized null tetrad from which the spin coefficients and Dirac equation are derived. Next, by proposing a generalized tortoise coordinate transformation, the Dirac equation is decoupled successfully near the event horizon surface. Finally, following the method of Damour and Ruffini, the temperature on the horizon surface and the thermal spectrum formula of Dirac particles are obtained. The result is also discussed.

Hawking Radiation of Dirac Particles in an Arbitrarily Accelerating Kinnersley Black Hole

Quantum thermal effect of Dirac particles in an arbitrarily accelerating Kinnersley black hole is investigated by using the method of generalized tortoise coordinate transformation. Both the location and the temperature of the event horizon depend on the advanced time and the angles. The Hawking thermal radiation spectrum of Dirac particles contains a new term which represents the interaction between particles with spin and black holes with acceleration. This spin-acceleration coupling effect is absent from the thermal radiation spectrum of scalar particles.

Hawking radiation of Weyl neutrinos in a rectilinearly non-uniformly accelerating Kinnersley black hole

The quantum thermal effect of Weyl neutrinos in a rectilinearly nonuniformly accelerating Kinnersley black hole is investigated by using a method of generalized tortoise coordinate transformation. The equation that determines the location, the Hawking temperature of the event horizon and the thermal radiation spectrum of neutrinos are derived. Our results show that the location and the temperature of the event horizon depend not only on the time but also on the angle.