Hawking radiation of five-dimensional rotating black hole

Applying the Damour–Ruffini method, we have considered the Hawking radiation of the five-dimensional rotating black hole. When taking the energy conservation and angular momentum conservation into consideration and considering the reaction of the radiation of the particle to spacetime, we see that the exact radiation spectrum is not purely thermal and the angular momentum of the black hole is quantized.     

Kerr-Newman黑洞的辐射谱

运用Damour-Ruffini方法研究Kerr-Newman黑洞粒子的Hawking辐射.在保持时空中总能量,总角动量和总电荷守恒的条件下,考虑辐射粒子对时空的反作用后,得到黑洞辐射谱不再是严格的纯热谱.在该结论中,不但含有辐射粒子能量的影响项,而且含有辐射粒子角动量对黑洞角动量的影响项.所给表达式与用隧穿方法得到的表达式一致.满足量子力学的幺正性原理.     

Kerr-Newman-de Sitter黑洞辐射谱和熵修正

本文延拓Damour-Ruffini方法,研究Kerr-Newman-de Sitter黑洞的Hawking辐射.在保持时空中总能量,总角动量和总电荷守恒的条件下,考虑辐射粒子对时空的反作用与黑洞事件视界和宇宙视界的相互关联后,得到了黑洞辐射谱.此辐射不再是严格的纯热谱与黑洞事件视界和宇宙视界对应Bekenstein-Hawking熵变有关.研究发现其结果仍然符合幺正性原理.同时给出了黑洞Bekenstein-Hawking熵的修正项.使人们对黑洞热辐射的研究有了进一步的认识.     

Hawking radiation of Kerr–Newman–de Sitter black hole

We extend the classical Damour–Ruffini method and discuss Hawking radiation in Kerr–Newman–de Sitter (KNdS) black hole. Under the condition that the total energy, angular momentum and charge of spacetime are conserved, taking the reaction of the radiation of the particle to the spacetime and the relation between the black hole event horizon and the cosmological horizon into consideration, we derive the black hole radiation spectrum. The radiation spectrum is no longer a pure thermal one. It is related to the change of the Bekenstein–Hawking entropy corresponding the black hole event horizon and the cosmological horizon. It is consistent with the underlying unitary theory.     

Kerr-Newman-de Sitter黑洞辐射谱和熵修正

本文延拓Damour-Ruffini方法,研究Kerr-Newman-de Sitter黑洞的Hawking辐射.在保持时空中总能量,总角动量和总电荷守恒的条件下,考虑辐射粒子对时空的反作用与黑洞事件视界和宇宙视界的相互关联后,得到了黑洞辐射谱.此辐射不再是严格的纯热谱与黑洞事件视界和宇宙视界对应Bekenstein-Hawking熵变有关.研究发现其结果仍然符合幺正性原理. 同时给出了黑洞Bekenstein-Hawking熵的修正项. 使人们对黑洞热辐射的研究有了进一步的认识.     

Kerr-Newman-Kasuya Black Hole Tunnelling Radiation

The radiation of black hole contributes to the shrinking of the event horizon such that the background spacetime should not be fixed. In this study we take into account the self-gravitation effect to study the radiation of Kerr Newman-Kasuya black hole as tunnelling. Using the facts of energy conservation and angular momentum conservation we derive the tunnelling rate and show that the spectrum of the radiation as tunnelling is not purely thermal.     

Bare and effective fluid description in brane world cosmology

We extend the classical Damour–Ruffini method and discuss Hawking radiation spectrum of high-dimensional rotating black hole using Tortoise coordinate transformation defined by taking the reaction of the radiation to the spacetime into consideration. Under the condition that the energy and angular momentum are conservative, taking self-gravitation action into account, we derive Hawking radiation spectrums which satisfy unitary principle in quantum mechanics. It is shown that the process that the black hole radiates particles with energy ω is a continuous tunneling process. We provide a theoretical basis for further studying the physical mechanism of black-hole radiation.     

A New Method to Study Hawking Radiation from the Kerr-Newman-NUT Black Hole

Following Hamilton-Jacobi method, we have investigated the Hawking radiation of Kerr-Newman-NUT black hole. We have considered the spacetime background dynamical and incorporate the self-gravitation effect of the emitted particles when energy conservation and angular momentum conservation are taken into account. We have found that the emission rate at the event horizon is equal to the difference of Bekenstein-Hawking entropy before and after emission.     

Tunneling and Temperature of Demiański-Newman Black Holes

We investigate Hawking radiation of charged and magnetized (scalar /fermion) particles from Demiański-Newman (DN) black holes using Hamilton-Jacobi (HJ) ansatz. Taking into account conservation of energy and the backreaction of particles to the spacetime, we calculate the emission rate and find it proportional to the change of Bekenstein-Hawking entropy. The radiation spectrum deviates from the precisely thermal one and is accordant with that obtained by the null geodesic method, but its physical picture is more clear. The investigation specifies a quantum-corrected radiation temperature dependent on the black hole background and the radiation particle’s energy, angular momentum, and charges.     

From Schwarzschild to Kerr due to Black Hole Quantum Tunnelling

Hawking radiation can be viewed as a process of quantum tunnelling near black hole horizon. When a particle with angular momentum tunnels across the event horizon of Schwarzschild black hole, the black hole will change into a Kerr black hole. The emission rate of the massless particles with angular momentum is calculated, and the result is consistent with an underlying unitary theory.     

Charged Particles’ Tunneling from Hot-NUT-Kerr-Newman-Kasuya Spacetime

We study the Hawking radiation as charged particles’ tunneling across the horizons of the Hot-NUT-Kerr-Newman-Kasuya spacetime by considering the spacetime background as dynamical and incorporating the self-gravitation effect of the emitted particles when the energy conservation, the angular momentum conservation, and the electric charge conservation are taken into account. Our result shows that the tunneling rate is related to the change of Bekenstein-Hawking entropy and the radiant spectrum is not pure thermal, but is consistent with an underlying unitary theory. The emission process is a reversible one, and the information is preserved as a natural result of the first law of black hole thermodynamics. To my teacher late Prof. Mainuddin Ahmed.     

匀加速直线运动的Kerr黑洞的非热效应

研究了匀加速直线运动的Kerr黑洞周围时空中的自发辐射.得到了发生自发辐射的能量条件,它不仅依赖于黑洞的角动量和加速度,而且还与黑洞的变化有关 关键词： 动态Kerr黑洞 非热辐射     

Binary-black-hole encounters, gravitational bursts, and maximum final spin

The spin of the final black hole in the coalescence of nonspinning black holes is determined by the "residual" orbital angular momentum of the binary. This residual momentum consists of the orbital angular momentum that the binary is not able to shed in the process of merging. We study the angular momentum radiated, the spin of the final black hole, and the gravitational bursts in a sequence of equal mass encounters. The initial orbital configurations range from those producing an almost direct infall to others leading to numerous orbits before infall, with multiple bursts of radiation. Our sequence consists of orbits with fixed impact parameter. What varies is the initial linear momentum of the black holes. For this sequence, the final black hole of mass M_{h} gets a maximum spin parameter a/M_{h} approximately 0.823, with this maximum occurring for initial orbital angular momentum L/M_{h};{2} approximately 1.176.     

Gravitational radiation from an extreme Kerr black hole

We analytically investigate gravitational radiation induced by a test particle falling into an extreme Kerr black hole. Assuming the radiation is dominated by the infinite sequence of quasi-normal modes which has the limiting frequencym/(2M), wherem is an azimuthal eigenvalue andM is the mass of the black hole. we find the radiated energy diverges logarithmically in time. Then we evaluate the back reaction to the black hole by appealing to the energy and angular momentum conservation laws. We find the radiation has a tendency to increase the ratio of the angular momentum to mass of the black hole, which is completely different from the non-extreme case, while the contribution of the test particle is to decrease it.     

Hawking Radiation of Charged Particles from a Rotating Black String

Using Damour-Ruffini method, Hawking radiation of rotating black strings is studied. Under the condition that the total energy, total angular momentum and total charge are conservative, the transition probability from initial state (energy M+ω, charge Q+e and angular momentum J+m) to final state (energy M, charge Q and angular momentum J) for black strings is derived considering the reaction of radiation particles to spacetime. That is, the probability that black strings radiate particles with energy ω, charge e and angular momentum m is obtained. The real spectrum is not a strictly pure thermal spectrum. Our result is consistent with Parikh and Wilczek’s result. It satisfies the unitary principle of quantum mechanics. However, in our result there are not only the term that denotes effect of energy and charge of radiation particles but also the term that denotes effect of radiation particles angular momentum on rotating black strings angular momentum. We provide a new way for investigating radiation of black strings.     

Quantum tunnelling radiation of Einstein-Maxwell-Dilaton-Axion black hole

By taking the energy conservation and angular momentum conservation into account, the characteristics of the quantum-tunnelling radiation of Einstein--Maxwell--Dilaton--Axion black hole are studied and the result shows that the tunnelling rate of such a black hole is relevant to Bekenstein--Hawking entropy and that the obtained radiation spectrum is not pure thermal.     

Exact solutions of the Klein–Gordon equation in the Kerr–Newman background and Hawking radiation

This work considers the influence of the gravitational field produced by a charged and rotating black hole (Kerr–Newman spacetime) on a charged massive scalar field. We obtain exact solutions of both angular and radial parts of the Klein–Gordon equation in this spacetime, which are given in terms of the confluent Heun functions. From the radial solution, we obtain the exact wave solutions near the exterior horizon of the black hole, and discuss the Hawking radiation of charged massive scalar particles.     

Confluent Heun functions and the physics of black holes: Resonant frequencies,Hawking radiation and scattering of scalar waves

We apply the confluent Heun functions to study the resonant frequencies (quasispectrum), the Hawking radiation and the scattering process of scalar waves, in a class of spacetimes, namely, the ones generated by a Kerr–Newman–Kasuya spacetime (dyon black hole) and a Reissner–Nordström black hole surrounded by a magnetic field (Ernst spacetime). In both spacetimes, the solutions for the angular and radial parts of the corresponding Klein–Gordon equations are obtained exactly, for massive and massless fields, respectively. The special cases of Kerr and Schwarzschild black holes are analyzed and the solutions obtained, as well as in the case of a Schwarzschild black hole surrounded by a magnetic field. In all these special situations, the resonant frequencies, Hawking radiation and scattering are studied.     

Observers in Kerr spacetimes: the ergoregion on the equatorial plane

We perform a detailed analysis of the properties of stationary observers located on the equatorial plane of the ergosphere in a Kerr spacetime, including light-surfaces. This study highlights crucial differences between black hole and the super-spinner sources. In the case of Kerr naked singularities, the results allow us to distinguish between “weak” and “strong ” singularities, corresponding to spin values close to or distant from the limiting case of extreme black holes, respectively. We derive important limiting angular frequencies for naked singularities. We especially study very weak singularities as resulting from the spin variation of black holes. We also explore the main properties of zero angular momentum observers for different classes of black hole and naked singularity spacetimes.