Narrow Results

Hawking radiation emanating from two-dimensional charged and uncharged dilatonic black holes — dimensionally reduced from (2+1) spinning and spinless, respectively, BTZ black holes — is viewed as a tunneling process. Two-dimensional dilatonic black holes (AdS(2) included) are treated as dynamical background in contrast to the standard methodology where the background geometry is fixed when evaluating Hawking radiation. This modification to the geometry gives rise to a nonthermal part in the radiation spectrum. Nonzero temperature of the extremal two-dimensional charged black hole is found. The Bekenstein–Hawking area formula is easily derived for these dynamical geometries.

Micron-sized black holes do not necessarily have a constant horizon temperature distribution. The black hole remote-sensing problem means to find out the "surface" temperature distribution of a small black hole from the spectral measurement of its (Hawking) grey pulse. This problem has been previously considered by Rosu, who used Chen's modified Möbius inverse transform. Here, we hint on a Ramanujan generalization of Chen's modified Möbius inverse transform that may be considered as a special wavelet processing of the remote-sensed grey signal coming from a black hole or any other distant grey source.

The stress–tensor of a massless scalar field satisfying Robin boundary conditions on two one-dimensional wall in two-dimensional Schwarzschild background is calculated. We show that vacuum expectation value of stress–tensor can be obtained explicitly by Casimir effect, trace anomaly and Hawking radiation.

In this paper, Parikh's recent work, which treats Hawking radiation as a tunneling process in a spherically symmetric spacetime, is extended to the stationary axisymmetric Kerr spacetime. A generalized Painleve coordinate system (Painleve–Kerr coordinates) is introduced. The new coordinates are well-behaved at the event horizon. Constant-time slices are just flat Euclidean space in radial and satisfy Landau's condition of clock synchronization. The tunneling process across the Kerr black hole event horizon is investigated and the correctd radiation spectrum is obtained. The result is consistent with an underlying unitary theory.

There has been recent speculation that the tunneling paradigm for Hawking radiation could — after quantum-gravitational effects have suitably been incorporated — provide a means for resolving the (black hole) information loss paradox. A prospective quantum-gravitational effect is the logarithmic-order correction to the Bekenstein–Hawking entropy/area law. In this paper, it is demonstrated that, even with the inclusion of the logarithmic correction (or, indeed, the quantum correction up to any perturbative order), the tunneling formalism is still unable to resolve the stated paradox. Moreover, we go on to show that the tunneling framework effectively constrains the coefficient of this logarithmic term to be non-negative. Significantly, the latter observation implies the necessity for including the canonical corrections in the quantum formulation of the black hole entropy.

Recently, Angheben et al.¹ have presented a refined method for calculating the (tree-level) black hole temperature by way of the tunneling paradigm. Here, we demonstrate how their formalism can be suitably adapted to accommodate the (higher-order) effects of the gravitational back-reaction.

The emergence of quantum-gravity induced corrective terms for the probability of emission of a particle from a black hole in the Parikh–Wilczek tunneling framework is studied. It is shown, in particular, how corrections might arise from modifications of the surface gravity due to near horizon Planck-scale effects. Our derivation provides an example of the possible linking between Planck-scale departures from Lorentz invariance and the appearance of higher order quantum gravity corrections in the black-hole entropy-area relation.

Parikh–Wilczek tunnelling framework is investigated again. We argue that Parikh–Wilczek's treatment, which satisfies the first law of black hole thermodynamics and consists with an underlying unitary theory, is only suitable for a reversible process. Due to the negative heat capacity, an evaporating black hole is a highly unstable system. That is, the factual emission process is irreversible, the unitary theory will not be satisfied and information loss is possible.

In the past, Hawking radiation was viewed as a tunneling process and the barrier was just created by the outgoing particle itself. In this paper, Parikh's recent work is extended to the case of massive particles' tunneling. We investigate the behavior of the tunneling massive particles from a particular black hole solution — G.H. Dilaton black hole which is obtained from the string theory, and calculate the emission rate at which massive particles tunnel across the event horizon. We obtain that the result is also consistent with an underlying unitary theory. Furthermore, the result takes the same functional form as that of massless particles.

By using a massless scalar field we examine the effect of an extra dimension on black hole radiation. As the equations are coupled, we find that the structure of the fifth dimension (as for membrane and induced-matter theory) affects the nature of the radiation observed in four-dimensional spacetime. In the case of the Schwarzschild–de Sitter solution embedded in a Randall–Sundrum brane model, the extension of the black hole along the fifth dimension looks like a black string. Then it is shown that, on the brane, the potential barrier surrounding the black hole has a quantized as well as a continuous spectrum. In principle, Hawking radiation may thus provide a probe for higher dimensions.

In this paper, we first rewrite the Lagrangian density of the electromagnetic field corresponding to the source with electric and magnetic charges. Then, in the background of Reissner–Nordström black hole spacetime, we extend the Parikh–Wilczek tunneling framework and calculate the emission spectrum of the outgoing particles with electric and magnetic charges. For the sake of simplicity, we only consider the case that the rate of electric and magnetic charge of the emission particle is constant and equals that of the black hole. In this case, the emission spectrum deviates from the pure thermal spectrum, but it is consistent with an underlying unitary theory and takes the same functional form as that of the uncharged massless particles. Finally, a discussion about the result is presented.

Hawking radiation from a general Kerr–Newman black hole is investigated using Damour–Ruffini's method. Considering the back-reaction of particle's energy, charge and angular momentum to the spacetime, we obtain a modified nonthermal spectrum. Maybe the information loss paradox can be explained, furthermore, the result is also consistent with the result obtained using Parikh and Wilczek's method.

Hawking radiation viewed as a semiclassical tunneling process of particles from the event horizon of general static black holes is investigated by taking the back-reaction of the emitted particles into account. In a general static spacetime, the emission rates of massless, massive and massive charged particles are computed respectively and the tunneling probabilities are obtained. Our results show that when energy and charge conservation are incorporated into the radiation process, the emission rate of the tunneling particles is related to changes of the Bekenstein-Hawking entropies of the black hole before and after the emission, thus it is consistent with an underlying unitary theory. The present results are obtained in a general way, no matter what the special static metric function is, and hence a generalization for the results found in the literature is given. Some remarks on the tunneling method are presented.

Wilczek and his collaborators' anomaly cancellation approach is applied to the 3D Schwarzschild- and BTZ-like braneworld black holes induced by the generalized metrics in the Randall–Sundrum scenario. Based on the fact that the horizon of braneworld black hole will extend into the bulk spacetime, calculation is done from the bulk generalized metrics side and it is shown that this approach also reproduces the correct Hawking radiation for these braneworld black holes. Besides, since this approach does not involve the dynamical equation, it is also shown that the Hawking radiation is only a kinematic effect.

We study Hawking radiation of fermions from a (4+n)-dimensional rotating black hole on the brane in terms of the fermions tunneling formalism, proposed by Kerner and Mann recently. To choose the Gamma matrices properly and avoid the ergosphere dragging effect, we perform it in the dragging coordinate frame. We obtain the tunneling rate and emission temperature of fermions which are consistent with the case of scalar particles as expected.

The fermions tunneling formulism of Kerner and Mann is extended to the case of black holes with electric and magnetic charges. As the electric and magnetic fields would couple with gravity field, we introduce the Dirac equation of charged and magnetized particles. We study the spin-up particles from the Reissner–Nordström black hole with magnetic charges and spin-down particles from the Kerr–Newman–Kasuya black hole and obtain the corresponding emission temperatures. In particular, we also provide a simplified method by defining an equivalent charge and gauge potential to further discuss tunneling of charged and magnetized fermions, which reproduces the same results as obtained above.

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.

We show, in different ways, that in the ubiquitous phenomenon of black body radiation there exists a minimum and maximum temperature. These limiting values are so small and large respectively, that they are of no practical use, except in an extreme situation of black hole evaporation where they lead to maximum and minimum mass.

Hawking radiation on the apparent horizon of a Vaidya black hole is investigated using Parikh's tunneling method. When back-reaction of particles is neglected, precisely thermal spectrum can be obtained. Then the black hole thermodynamics can be built successfully on the apparent horizon. When a relativistic perturbation is given to the apparent horizon, similar calculation can also lead to a purely thermal spectrum, which is corresponding to a modified temperature from the former. The first law of thermodynamics can also be constructed successfully at a new supersurface which has a small deviation from the apparent horizon. When the event horizon is thought as such a deviation from the apparent horizon, the expressions of the characteristic position and temperature are consistent with the previous viewpoint which asserts that the thermodynamics should be built on the event horizon. It is concluded that the thermodynamics should be constructed on the apparent horizon exactly while the event horizon thermodynamics is just one of the perturbations near the apparent horizon.

In this paper, the Hawking radiation from the slowly varying nonstationary Reissner–Nordström black hole is discussed through the fermions tunnelling theory, assuming a reasonable form of gamma matrix, and even researching on the issues with following coordinate transformation, which is a new method to study fermions' Hawking tunnelling radiation from slowly varying nonstationary Reissner–Nordström black hole.