Einstein Maxwell Dilaton Axion Black Hole Research Articles

Chaotic motion of scalar particle coupling to Chern–Simons invariant in the stationary axisymmetric Einstein–Maxwell dilaton black hole spacetime

We investigate the motion of a test scalar particle coupling to the Chern–Simons (CS) invariant in the background of a stationary axisymmetric black hole in the Einstein–Maxwell–Dilaton–Axion (EMDA) gravity. Comparing with the case of a Kerr black hole, we observe that the presence of the dilation parameter makes the CS invariant more complex, and changes the range of the coupling parameter and the spin parameter where the chaotic motion appears for the scalar particle. Moreover, we find that the coupling parameter together with the spin parameter also affects the range of the dilation parameter where the chaos occurs. We also probe the effects of the dilation parameter on the chaotic strength of the chaotic orbits for the coupled particle. Our results indicate that the coupling between the CS invariant and the scalar particle yields the richer dynamical behavior of the particle in the rotating EMDA black hole spacetime.

Lorentz invariance violation and modified Hawking fermions tunneling radiation of stationary axially symmetric black holes

Based on a higher energy scale, the dispersion relation might be corrected. Correspondingly, the Hamilton–Jacobi equation should also be modified. In this paper, we use the correction to study the fermion tunneling radiation for a Gibbons–Maeda–Garfinkle-Horowitz–Strominger (GMGHS) black hole, a Kerr–NUT black hole, and an Einstein–Maxwell–Dilaton–Axion (EMDA) black hole. The result shows that compared to the charged GMGHS black hole and the rotating Kerr–NUT black hole, the Hawking temperate and the entropy of the rotating charged EMDA black hole not only are related to the correction parameter [Formula: see text] and particle mass [Formula: see text] but also depend on the angle parameter [Formula: see text] of the black hole coordinates.

Examining the weak cosmic censorship conjecture by gedanken experiments for an Einstein–Maxwell–Dilaton–Axion black hole

In the framework of the new version of the gedanken experiments proposed by Sorce and Wald, we investigate the weak cosmic censorship conjecture (WCCC) for an Einstein–Maxwell–Dilaton–Axion (EMDA) black hole. Our result shows that no violations of WCCC can occur with the increase of the background solution parameters for this near-extremal EMDA black hole when the second-order correction of the perturbations is taken into account. Namely, the near-extremal EMDA black hole cannot be over-charged or over-spun.

Influence of modified light dispersion theory on fermion tunneling radiation in the Einstein–Maxwell–dilaton–axion black hole**This work was supported by the National Natural Science Foundation of China (grant 11273020), the Sichuan Science and Technology Program (grant 2018JY0502) and the Natural Science Foundation of Shandong Province (grant ZR2019MA059).

Based on a light dispersion relationship derived from string theory and quantum gravitational theory, we make an accurate modification to the quantum tunneling radiation rate and black hole temperature at an event horizon in a stationary axial-symmetric Einstein–Maxwell–dilaton–axion black hole. We also analyze our new results and carry out some significant discussions. This work enriches the research content and methods of the frontiers of black hole physics.

Quasi-Local Masses of Rotating Space-Times**Supported by the National Natural Science Foundation of China under Grant No. 11405016, and Basic Research Project of Science and Technology Committee of Chongqing under Grant No. cstc2016jcyja0364

We derive the Misner-Sharp-like masses of the Reissner–Nordström black hole and the Einstein–Maxwell–Dilaton–Axion black hole by using the modified first law of thermodynamics. Their surface tensions are investigated. For the Reissner–Nordström black hole, the outer horizon radius is treated as a variable and the effective temperature is introduced. For the Einstein–Maxwell–Dilaton–Axion black hole, the outer horizon radius, the angular momentum unit mass and the parameter b are seen as three independent variables, and the mass, the horizon area and the angular momentum are functions of them.

Spectroscopy of the Einstein–Maxwell–Dilaton–Axion black hole

The entropy spectrum of a spherically symmetric black hole was derived via the Bohr-Sommerfeld quantization rule in Majhi and Vagenas's work. Extending this work to charged and rotating black holes, we quantize the horizon area and the entropy of an Einstein-Maxwell-Dilaton-Axion (EMDA) black hole via the Bohr-Sommerfeld quantization rule and the adiabatic invariance. The result shows the area spectrum and the entropy spectrum are respectively equally spaced and independent on the parameters of the black hole.

Absorption Cross Section and Decay Rate of Stationary Axisymmetric Einstein–Maxwell Dilaton Axion Black Hole

The low energy absorption cross section and the decay rate of the stationary Axisymmetric Einstein–Maxwell Dilaton Axion black hole for massless scalar particles is calculated analytically. It is shown that the partial absorption cross section increases as the rotating parameter a and the absolute value of the dilaton D decreases. It is also shown that the partial absorption cross section is not always positive due to superradiance factor ω–mΩ. However, the decay rate of this black hole is always positive.

Quantum corrections to the entropy of Einstein–Maxwell dilaton–axion black holes

We study the corrections to the entropy of Einstein-Maxwell dilaton-axion black holes beyond semiclassical approximations. We consider the entropy of the black hole as a state variable and derive these corrections using the exactness criteria of the first law of thermodynamics. We note that from this general frame-work the entropy corrections for "simpler" black holes like Schwarzschild, Reissner-Nordstr\"{o}m and anti-de Sitter-Schwarzschild black holes follow easily. This procedure gives us the modified area law as well.

Hawking radiation of dyon particles from the Einstein –Maxwell-Dilaton–Axion black hole via covariant anomaly

Hawking radiation of particles with electric and magnetic charges from the Einstein–Maxwell-Dilaton–Axion black hole is derived via the anomaly cancellation method, initiated by Robinson and Wilczek and elaborated by Banerjee and Kulkarni recently. We reconstruct the electromagnetic field tensor to redefine the gauge potential and equivalent charge corresponding to the source with electric and magnetic charges. We only adopt the covariant gauge and gravitational anomalies to discuss the near-horizon quantum anomaly in the dragging coordinate frame. Our result shows that Hawking radiation in this case also can be reproduced from the viewpoint of anomaly.

Quasinormal frequencies and thermodynamic instabilities for the stationary axisymmetric Einstein-Maxwell dilaton-axion black hole

The massless scalar quasinormal frequencies of a stationary axisymmetric Einstein-Maxwell dilaton-axion (EMDA) black hole are investigated by using Leaver's continued fraction method. It is shown that in the complex plane the frequencies move counterclockwise and get a spiral-like shape as the angular momentum per unit mass a increases to its extremal value or the dilaton D decreases to its extremal value for the rotating black hole. However, for the non-rotating Garfinkle-Horowitz-Strominger dilaton (GHSD) black hole, the dilaton parameter D, which is related to the electric charge of this EMDA black hole, cannot make the frequencies spire in the complex ω plane, which is qualitatively different from the charge of the Reissner-Nordstrom (RN) black hole. The so-call ``Spiral-like Criterion" is obtained and it points out that the frequencies won't spire in the complex ω plane if the heat capacity for the considered black hole is always negative and vice versa. The most interesting outcome of our calculation is that the critical point, at which the imaginary part of the wave function related to time-dependent part (e−iωt) begins to oscillate obviously for the given quantum number, is just the second order phase transition point of Davies. The fact seems to imply that there is some relation between the dynamical evolution and thermodynamic instabilities for the black hole.

Quasinormal modes of a stationary axisymmetric EMDA black hole

The massless scalar quasinormal modes (QNMs) of a stationary axisymmetric Einstein–Maxwell dilaton–axion (EMDA) black hole are calculated numerically using the continued fraction method first proposed by Leaver. The fundamental quasinormal frequencies (slowly damped QNMs) are obtained and the peculiar behaviours of them are studied. It is shown that these frequencies depend on the dilaton parameter D, the rotational parameter a, the multiple moment l and the azimuthal number m and have the same values with other authors at the Schwarzschild and Kerr limit.

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.

Late-time tails in a stationary axisymmetric EMDA black hole geometry

The late-time tails of massless and self-interacting (SI) (massive) scalar fields are investigated analytically in a stationary axisymmetric Einstein–Maxwell dilaton-axion (EMDA) black hole geometry. It is shown that the asymptotic behaviour of massless perturbations is dominated by an inverse power-law decaying tail and the intermediate asymptotic behaviour of SI (massive) perturbations is dominated by an oscillatory one.

Asymptotic Tails of Massive Scalar Fields in a StationaryAxisymmetric EMDA Black Hole Geometry

The late-time tail behaviour of massive scalar fields is studiedanalytically in a stationary axisymmetric Einstein–MaxwellDilaton–Axion (EMDA) black hole geometry. Itis shown that the asymptotic behaviour of massive perturbations isdominated by the oscillatory inverse power-law decaying tailt−(l+3/2)sin (μt) at the intermediate late times, and by theasymptotic tail t−5/6sin (μt) at asymptotically late times,with μ being field mass. Our result seems to suggest that theintermediate tails t−(l+3/2)sin (μt) and the asymptoticallytails t−5/6sin (μt) may be a quite general feature forevolution of massive scalar fields in any four-dimensionalasymptotically flat rotating black hole backgrounds.

Entropy of Einstein-Maxwell-Dilaton-Axion Black Holes

The entropy of Einstein—Maxwell-dilaton—axion black holes is calculated by using the improved brick-wall model. Taking into account of the statistical physics, we propose not to consider the superradiant modes. The result shows that the nonsuperradiant modes do contribute exactly the area-law entropy for extreme black hole. Moreover, our cut-off e which does not require an angular cut-off δ is independent of angle θ. As for the extreme black hole, we found that its entropy is zero.

Conformal mechanics on rotating Bertotti–Robinson spacetime

We investigate conformal mechanics associated with the rotating Bertotti–Robinson (RBR) geometry found recently as the near-horizon limit of the extremal rotating Einstein–Maxwell dilaton–axion black holes. The solution breaks the SL(2, R)× SO(3) symmetry of Bertotti–Robinson (BR) spacetime to SL(2, R)× U(1) and breaks supersymmetry in the sence of N=4, d=4 supergravity as well. However, it shares with BR such properties as confinement of timelike geodesics and discreteness of the energy of test fields on the geodesically complete manifold. Conformal mechanics governing the radial geodesic motion coincides with that for a charged particle in the BR background (a relativistic version of the de Alfaro–Fubini–Furlan model), with the azimuthal momentum playing the role of a charge. Similarly to the BR case, the transition from Poincaré to global coordinates leads to a redefinition of the Hamiltonian making the energy spectrum discrete. Although the metric does not split into a product space even asymptotically, it still admits an infinite-dimensional extension of SL(2, R) as asymptotic symmetry. The latter is shown to be given by the product of one copy of the Virasoro algebra and U(1), the same being valid for the extremal Kerr throat.

Nernst Theorem and Entropy of the Axisymmetric Einstein–Maxwell–Dilaton-Axion Black Hole

The free energy and the entropy of scalar field are calculated by brick-wall in the axisymmetric Einstein–Maxwell–Dilaton-axion black hole. It is shown that when the black hole has inner and outer horizons, the entropy is not only related to the area of an outer horizon but also is the function of the area of an inner horizon. When the area of an inner horizon approaches zero, we can obtain the known conclusion. The entropy expressed by location parameter of outer horizon and inner horizons approaches absolute zero. It obeys Nernst theorem. It can be taken as Planck absolute entropy of a black hole.

Entropy of the Nonminimally Coupled Quantum Scalar Fields in a Stationary Axisymmetric Einstein-Maxwell Dilaton-Axion Black Hole

The statistical-mechanical entropy of the stationary axisymmetric Einstein-Maxwell dilaton-axion black hole is investigated by using the "brick wall" model in which the original Dirichlet condition is replaced by a scattering ansatz for the field functions at the event horizon and regularized with the Pauli-Villars scheme. It is also shown, for the Kerr black hole, that the statistical-mechanical entropy obtained from our derivation coincides with the one-loop correction to its thermodynamical entropy obtained by the conical singularity method.

Quantum entropy of a nonextreme stationary axisymmetric black hole due to a minimally coupled quantum scalar field

By using the 't Hooft "brick wall" model and the Pauli-Villars regularization scheme we calculate the statistical-mechanical entropy arising from the minimally coupled scalar fields which rotate with the azimuthal angular velocity $\Omega_0=\Omega_H$ ($\Omega_H$ is the angular velocity of the black hole horizon) in the general four-dimensional non-extreme stationary axisymmetric black hole space-time. We also show, for the Kerr-Newman and the Einstein-Maxwell dilaton-axion black holes, that the statistical-mechanical entropy obtained from our derivation and the quantum thermodynamical entropy by the conical singularity method are equivalent.

Thermodynamics of stationary axisymmetric Einstein-Maxwell dilaton-axion black hole

The thermodynamics of a stationary axisymmetric Einstein-Maxwell dilaton-axion (EMDA) black hole is investigated using general statistical physics methods. It is shown that entropy and energy have the same form as for the Kerr-Newman charged black hole, but temperature, heat capacity and chemical potential have a different form. However, it is shown that the Bardeen-Carter-Hawking laws of black hole thermodynamics are valid for the stationary axisymmetric EMDA black hole. The black hole possesses second-order phase transitions as does the Kerr-Newman black hole because its heat capacity diverges but both the Helmholtz free energy and entropy are continuous at some value of J and Q. Another interesting result is that the action I can be expressed as I= S + βΩ r h J for general stationary black holes in which the external material contribution to mass and angular momentum vanishes. When J = 0, i.e., for static black holes, the result reduces to I = S.