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.

Discussion of Garfinkle-Horowitz-Strominger Dilaton Black Hole Entropy

We discuss the entropy of the Garfinkle-Horowitz-Strominger dilaton black hole by using the thin film brick-wall model, and the entropy obtained is proportional to the horizon area of the black hole confirming the Bekenstein-Hawking＇s area-entropy formula. Then, by comparing with the original brick-wall method, we find that the result obtained by the thin film method is more reasonable avoiding some drawbacks, such as little mass approximation, neglecting logarithm term, and taking the term L^3 as a contribution of the vacuum surrounding the black hole, and the physical meaning of the entropy is more clearer.

Abbott-Deser-Tekin Charge of Dilaton Black Holes with Squashed Horizons

We consider the conserved charge of static black holes with squashed horizons in the Einstein-Maxwell-dilaton theory via both the Abbott-Deser-Tekin （ADT） method and its off-shell generalization. We first make use of the original ADT method to compute the mass of the dilaton squashed black holes in terms of three different reference spacetimes, which are the asymptotic geometry, the flat background and the spacetime of the Kaluza- Klein monopole with boundary matched to the original metric, respectively. Each mass satisfies the first law of black hole thermodynamics, although the mass computed on the basis of the boundary matching the Kaluza- Klein monopole is different from that of the other two reference spacetimes. Then the mass of the black holes is evaluated through the off-shell generalized ADT method.

Dilaton Black Hole Tunneling Radiation in de Sitter Universe

The Hawking radiation via tunneling from the dilaton black hole in de Sitter universe is investigated using Parikh Wilczek＇s method. We show that if the self-gravitational interaction and energy conservation are taken into account, the modified radiation spectrum deviates from exact thermal spectrum and satisfies the unitary theory.

Hawking radiation from the dilaton-(anti) de Sitter black hole via covariant anomaly

Adopting the anomaly cancellation method, initiated by Robinson and Wilczek recently, this paper discusses Hawking radiation from the dilaton-（anti） de Sitter black hole. To save the underlying gauge and general covariance, it introduces covariant fluxes of gauge and energy-momentum tensor to cancel the gauge and gravitational anomalies. The result shows that the introduced compensating fluxes are equivalent to those of a 2-dimensional blackbody radiation at Hawking temperature with appropriate chemical potential.

Consequences of Rényi entropy on the thermal geometries and Hawking evaporation of topological dyonic dilaton black hole

The thermodynamics of black holes(BHs)has had a profound impact on theoretical physics,providing insight into the nature of gravity,the quantum structure of spacetime and the fundamental laws governing the Universe.In this study,we investigate thermal geometries and Hawking evaporation of the recently proposed topological dyonic dilaton BH in anti-de Sitter(Ad S)space.We consider Rényi entropy and obtain the relations for pressure,heat capacity and Gibbs free energy and observe that the Rényi parameter and dilaton field play a vital role in the phase transition and stability of the BH.Moreover,we use Weinhold,Ruppeiner and Hendi Panahiyah Eslam Momennia models to evaluate the scalar curvature of the BH and find out that the divergence points of the scalar curvature coincides with the zero of specific heat.Finally,using Stefan–Boltzmann law,we determine that the BH without a dilaton field evaporates far more quickly compared to the dilaton BH in Ad S space.

Garfinkle-Horowitz-Stromingen dilaton黑洞的Hawking隧穿辐射

用量子隧穿法研究Garfinkle-Horowitz-Stromingen dilaton黑洞的Hawking辐射,得到了静止质量为零和不为零的两类粒子穿过黑洞事件视界的出射率,发现粒子的量子隧穿辐射谱与黑洞的Bekenstein-Hawking熵变有关,辐射谱不再是严格的纯热谱.

Absorption Cross Section of Static Einstein-Maxwell Dilation Axion Black Hole for Scalar Particles

The absorption cross section of the static Einstein-Maxwell dilaton axion （EMDA） black hole for scalar particles is investigated. It is shown that the ratio of the absorption cross section of the EMDA black hole to that of the Schwarzschild black hole decreases as the absolute value of the dilaton increases, and it becomes zero as the dilaton tends to its extremal value. It is also shown that the absorption cross section decreases as both the v and the absolute value of the dilaton increase, and it decreases as the mass of the particle decreases.

On the Dynamical 4D BTZ Black Hole Solution in Conformally Invariant Gravity

We review the (2 + 1)-dimensional Baňados-Teitelboim-Zanelli black hole solution in conformally invariant gravity, uplifted to (3 + 1)-dimensional spacetime. For the matter content we use a scalar-gauge field. The metric is written as where the dilaton field ω contains all the scale dependencies and where represents the “un-physical” spacetime. A numerical solution is presented and shows how the dilaton can be treated on equal footing with the scalar field. The location of the apparent horizon and ergo-surface depends critically on the parameters and initial values of the model. It is not a hard task to find suitable initial parameters in order to obtain a regular and singular free out of a BTZ-type solution for . In the vacuum situation, an exact time-dependent solution in the Eddington-Finkelstein coordinates is found, which is valid for the (2 + 1)-dimensional BTZ spacetime as well as for the uplifted (3 + 1)-dimensional BTZ spacetime. While resembles the standard BTZ solution with its horizons, is flat. The dilaton field becomes an infinitesimal renormalizable quantum field, which switches on and off Hawking radiation. This solution can be used to investigate the small distance scale of the model and the black hole complementarity issues. It can also be used to describe the problem of how to map the quantum states of the outgoing radiation as seen by a distant observer and the ingoing by a local observer in a one-to-one way. The two observers will use a different conformal gauge. A possible connection is made with the antipodal identification and unitarity issues. This research shows the power of conformally invariant gravity and can be applied to bridge the gap between general relativity and quantum field theory in the vicinity of the horizons of black holes.

Dilaton-Maxwell黑洞的量子隧穿辐射(英文)

对静态球对称的Dilaton-Maxwell黑洞霍金辐射的隧穿过程进行了简单直接的推导,因为推导过程中强调了能量守恒定律,故精确的辐射谱不再是纯热的.当考虑特殊情况时,所得的结果与已知的Schwarzschild隧穿辐射谱一致.

Joule-Thomson expansion of charged dilatonic black holes

Based on the Einstein-Maxwell theory,the Joule-Thomson(J-T)expansion of charged dilatonic black holes(the solutions are neither flat nor AdS)in(n+1)-dimensional spacetime is studied herein.To this end,we analyze the effects of the dimension n and dilaton fieldαon J-T expansion.An explicit expression for the J-T coefficient is derived,and consequently,a negative heat capacity is found to lead to a cooling process.In contrast to its effect on the dimension,the inversion curve decreases with charge Q at low pressures,whereas the opposite effect is observed at high pressures.We can observe that with an increase in the dimension n or parameter a,both the pressure cut-off point and the minimum inversion temperature T_(min)change.Moreover,we analyze the ratio T_(min)/T_(c)numerically and discover that the ratio is independent of charge;however,it depends on the dilaton field and dimension:for n=3 andα=0,the ratio is 1/2.The dilaton field is found to enhance the ratio.In addition,we identify the cooling-heating regions by investigating the inversion and isenthalpic curves,and the behavior of the minimum inversion mass M_(min)indicates that this cooling-heating transition may not occur under certain special conditions.

通过反常计算dilaton-axion黑洞的霍金辐射

利用Rob inson和W iczek提出的方法,我们从反常的角度研究了带电的d ilaton-axion黑洞的霍金辐射,为了得到规范不变量和广义规范不变量,引入了规范流和能动张量流,最后通过去除反常得到了在事件视界处的霍金温度,所得的结果与来自于普朗克分布的辐射谱的结果相一致.

新广义Tortiose坐标变换下动态Dilaton-Maxwell黑洞时空中的非热辐射研究

作者通过哈密顿-雅克比方程,在新乌龟坐标变换下,研究了Dilaton-Maxwell黑洞时空中的非热辐射特征,获得粒子能量所在的禁区宽度,以及出射粒子的最大能量.同时,根据方法我们还得出了该黑洞时空视界处的表面引力.

Fermions tunneling from the Horowitz-Strominger Dilaton black hole

Based on the work of Kerner and Mann, fermions tunneling from the Horowitz-Strominger Dilaton black hole on the membrane is studied. Owing to the coupling among electromagnetic field, matter field and gravity field, the Dirac equation of charged particles is introduced, and according to that, the expected emission temperature is obtained. After the self-gravitational interaction is considered, it is found that the tunneling rate of fermions also satisfies the underlying Unitary theory as the case of scalar particles.

The entropy of Garfinkle-Horne dilaton black hole due to arbitrary spin fields

Using the membrane model which is based on brick wall model, we calculated the free energy and entropy of Garfinkle-Horne dilatonic black hole due to arbitrary spin fields. The result shows that the entropy of scalar field and the entropy of Fermionic field have similar formulas. There is only a coefficient between them.

Dynamic phase transition of charged dilaton black holes

The dynamic phase transition of charged dilaton black holes is investigated in this paper.The Gibbs free energy landscape is introduced,and the corresponding G_(L) is calculated for the dilaton black hole.We numerically solve the Fokker-Planck equation constrained by only the reflecting boundary condition.The effects of dilaton gravity on the probabilistic evolution of dilaton black holes are explored.Firstly,the horizon radius difference between a large dilaton black hole and a small dilaton black hole increases with the parameterα.Secondly,with increasingα,the system needs much more time to achieve a stationary distribution.Finally,the values attained forρ(rl,t)andρ(rs,t)vary withα.Additionally,by resolving the Fokker-Planck equation constrained by both the reflecting boundary condition and absorbing boundary condition,we investigate the first passage process of dilaton black holes.The initial peak decays more slowly with increasingα,which can also be observed via the slowing decay ofΣ(t)(the sum of the probability of the black hole system not having completed a first passage by time t).Moreover,the time corresponding to the single peak of the first passage time distribution is found to increase with the parameterα.Considering these observations,the dilaton field is found to slow down the dynamic phase transition process between a large black hole and a small black hole.

Nonstatic solution of Dilaton-Maxwell compound field and Hawking radiation of its black hole

SINCE Balbinot studied the back reaction of the evaporation on the Hawking temperature of anonstatic radiating black hole by using and generalizing the method of Davies et al.,wideinterest has been aroused in this field.In general,radiation terms with Luminosity Lwere introduced into energy-momentum tensor in the course of deriving evaporating

Tunneling Radiation of Massive Vector Bosons from Dilaton Black Holes

It is well known that Hawking radiation can be treated as a quantum tunneling process of particles from the event horizon of black hole. In this paper, we attempt to apply the massive vector bosons tunneling method to study the Hawking radiation from the non-rotating and rotating dilaton black holes. Starting with the Proca field equation that govern the dynamics of massive vector bosons, we derive the tunneling probabilities and radiation spectrums of the emitted vector bosons from the static spherical symmetric dilatonic black hole, the rotating Kaluza–Klein black hole,and the rotating Kerr–Sen black hole. Comparing the results with the blackbody spectrum, we satisfactorily reproduce the Hawking temperatures of these dilaton black holes, which are consistent with the previous results in the literature.

稳态轴对称Sen黑洞的量子效应

借助乌龟坐标，得到了在稳态轴对称Ｓｅｎ黑洞视界附近的Ｋｌｅｉｎ－Ｇｏｒｄｏｎ方程的解，导出了Ｈａｗｋｉｎｇ热谱公式．通过与一般Ｅｉｎｓｔｅｉｎ黑洞比较，发现ｄｉｌａｔｏｎ场对黑洞的热力学性质有很大的影响．

Teleparallel equivalent theory of (1+1)-dimensional gravity

A theory of （1＋1）-dimensional gravity is constructed on the basis of the teleparallel equivalent of general relativity. The fundamental field variables are the tetrad fields ei^μ and the gravity is attributed to the torsion. A dilatonic spherically symmetric exact solution of the gravitational field equations characterized by two parameters M and Q is derived. The energy associated with this solution is calculated using the two-dimensional gravitational energy- momentum formula.