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Gravitational perturbations of the Einstein-Euler-Heisenberg black hole

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Chinese Physics C 2022年第8期46卷 287-300页

作者：罗智李瑾 Department of Physics Chongqing UniversityChongqing 401331China

The prospect of using gravitational wave detections via the quasinormal modes(QNMs) to test modified gravity theories is exciting area of current research.Gravitational waves(GWs) emitted by a perturbed black hole(BH) will decay as a superposition of their QNMs of oscillations at the ringdown phase.In this work,we investigate the QNMs of the Einstein-Euler-Heisenberg(EEH) BH for both axial and polar gravitational perturbations.We obtain master equations with the tetrad formalism,and the quasinormal frequencies of the EEH BH are calculated in the 6 th order Wentzel-Kramers-Brill?uin approximation.It is interesting to note that the QNMs of the EEH BH would differ from those of the Reissner-Nordstr?m BH under the EH parameter,which indicates the EH parameter would affect the gravitational perturbations for the EEH BH.

关键词： black hole quasinormal modes gravitational perturbation

Accurate correction of arbitrary spin fermion quantum tunneling from non-stationary Kerr-de Sitter black hole based on corrected Lorentz dispersion relation

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Chinese Physics C 2020年第12期44卷 226-233页

作者：沙贝刘志娥刘玉真谭霞张洁杨树政 School of Physics and Electronic Engineering Qilu Normal UniversityJinan 250200China College of Physics and Space Science China West Normal UniversityNanchong 637002China

According to a corrected dispersion relation proposed in the study on the string theory and quantum gravity theory,the Rarita-Schwinger equation was precisely modified,which resulted in the Rarita-Schwinger-Hamilton-Jacobi equation.Using this equation,the characteristics of arbitrary spin fermion quantum tunneling radiation from non-stationary Kerr-de Sitter black holes were determined.A number of accurately corrected physical quantities,such as surface gravity,chemical potential,tunneling probability,and Hawking temperature,which describe the properties of black holes,were derived.This research has enriched the research methods and enabled increased precision in black hole physics research.

关键词： black hole rermions tunneling radiation Lorentz dispersion relation

Spherical accretion flow onto general parameterized spherically symmetric black hole spacetimes

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Chinese Physics C 2021年第1期45卷 325-340页

作者：杨森刘诚朱涛赵力武强杨科 Mubasher Jamil Institute of theoretical physics Lanzhou UniversityLanzhou 730000China Institute for theoretical physics and Cosmology Zhejiang University of TechnologyHangzhou 310032China United center for gravitational wave physics(UCGWP) Zhejiang University of TechnologyHangzhou 310032China School of Physical Science and Technology Southwest UniversityChongqing 400715China School of Natural Sciences National University of Sciences and TechnologyIslamabad 44000Pakistan

The transonic phenomenon of black hole accretion and the existence of the photon sphere characterize strong gravitational fields near a black hole horizon.Here,we study the spherical accretion flow onto general parametrized spherically symmetric black hole spacetimes.We analyze the accretion process for various perfect fluids,such as the isothermal fluids of ultra-stiff,ultra-relativistic,and sub-relativistic types,and the polytropic fluid.The influences of additional parameters,beyond the Schwarzschild black hole in the framework of general parameterized spherically symmetric black holes,on the flow behavior of the above-mentioned test fluids are studied in detail.In addition,by studying the accretion of the ideal photon gas,we further discuss the correspondence between the sonic radius of the accreting photon gas and the photon sphere for general parameterized spherically symmetric black holes.Possible extensions of our analysis are also discussed.

关键词： spherical accretion black hole RZ parametrization phot on sphere

Joule–Thomson expansion of RN-AdS black hole immersed in perfect fluid dark matter

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Communications in Theoretical Physics 2021年第9期73卷 105-112页

作者： Yihe Cao Hanwen Feng Wei Hong Jun Tao Center for Theoretical Physics College of PhysicsSichuan UniversityChengdu610065China

In this paper,we study the Joule–Thomson expansion for RN-AdS black holes immersed in perfect fluid dark matter.As perfect fluid dark matter is one of the dark matter candidates,we are interested in how it influences the thermodynamic properties of black holes.Firstly,the negative cosmological constant could be interpreted as thermodynamic pressure and its conjugate quantity as the thermodynamic volume,which give us more physical insights into the black hole.Moreover,we derive the thermodynamic definitions and study the critical behaviour of the black hole.Secondly,the explicit expression of Joule–Thomson coefficient is obtained from the basic formulas of the pressure,the volume,the entropy and the temperature.Then,we obtain the inversion curves in terms of charge Q and parameterλ.Furthermore,we analyse the isenthalpic curve in T–P graph with the cooling–heating region determined by the inversion curve.At last,we derive the ratio of minimum inversion temperature to critical temperature and compare the result with that in the RN-AdS case.

关键词： Joule-Thomson expansion black hole perfect fluid dark matter

Effects of thermal fluctuations on the Kerr–Newman–NUT–AdS black hole

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Communications in Theoretical Physics 2021年第8期73卷 114-123页

作者： M Sharif Qanitah Ama-Tul-Mughani Department of Mathematics University of the PunjabQuaid-e-Azam CampusLahore-54590Pakistan

This paper is devoted to studying the impact of thermal fluctuations on thermodynamics of rotating as well as charged anti-de Sitter black holes with the Newman–Unti–Tamburino(NUT)parameter.To this end,we derive the analytic expression of thermodynamic variables,namely the Hawking temperature,volume,angular velocity,and entropy within the limits of extended phase space.These variables meet the first law of thermodynamics as well as the Smarr relation in the presence of new NUT charge.To analyze the effects of quantum fluctuations,we derive the exact expression of corrected entropy,which yields modification in other thermodynamical equations of state.The local stability and phase transition of the considered black hole are also examined through specific heat.It is found that the NUT parameter increases the stability of small black holes,while the logarithmic corrections induce instability in the system.

关键词： black hole thermal fluctuations thermodynamics NUT parameter

Thin accretion disk around a four-dimensional Einstein- Gauss-Bonnet black hole

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Chinese Physics C 2021年第1期45卷 366-374页

作者：刘诚朱涛武强 Institute for Theoretical Physics&Cosmology Zhejiang University of TechnologyHangzhou 310023China United Center for Gravitational Wave Physics(UCGWP) Zhejiang University of TechnologyHangzhou 310023China

Recently,a novel four-dimensional Einstein-Gauss-Bonnet(4 EGB) theory of gravity was proposed by Glavan and Lin [D.Glavan and C.Lin,Phys.Rev.Lett.124,081301(2020)],which includes a regularized GaussBonnet term using the re-scalaring of the Gauss-Bonnet coupling constant α→α/(D-4) in the limit D→4.This theory has also been reformulated to a specific class of the Homdeski theory with an additional scalar degree of freedom and to a spatial covariant version with a Lagrangian multiplier,which can eliminate the scalar mode.Here,we study the physical properties of the electromagnetic radiation emitted from a thin accretion disk around a static spherically symmetric black hole in 4 EGB gravity.For this purpose,we assume the disk is in a steady-state and in hydrodynamic and thermodynamic equilibrium,so that the emitted electromagnetic radiation is a black body spectrum.We study in detail the effects of the Gauss-Bonnet coupling constant α in 4 EGB gravity on the energy flux,temperature distribution,and electromagnetic spectrum of the disk.With an increase in the parameter α,the energy flux,temperature distribution,and electromagnetic spectrum of the accretion disk all increase.We also show that the accretion efficiency increases with the growth of the parameter α.Our results indicate that the thin accretion disk around a static spherically symmetric black hole in 4 EGB gravity is hotter,more luminous,and more efficient than that around a Schwarzschild black hole with the same mass for positive α,while it is cooler,less luminous,and less efficient for negative α.

关键词： black hole thin accretion disk moditled gravity

Hawking temperature of Kerr anti-de-Sitter black hole affected by Lorentz symmetry violating

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Communications in Theoretical Physics 2021年第4期73卷 99-103页

作者：刘志娥谭霞张洁杨树政 College of Physics and Electronic Engineering Qilu Normal UniversityJinan 250200China Department of Astronomy China West Normal UniversityNanchong 637002China

We studied the correction of the quantum tunneling radiation of fermions with spin 1/2 in Kerr anti-de-Sitter black hole.First,the dynamic equation of spin 1/2 fermions was corrected using Lorentz’s violation theory.Second,the new expressions of the fermions quantum tunneling rate,the Hawking temperature of the black hole and the entropy of the black hole were obtained according to the corrected fermions dynamic equation.Our results show that Hawking temperature increases with the enhancement of both the coupling strength and the radial component of ether-like field,but is independent of non-radial components of ether-like field.At last,some comments are made on the results of our work.

关键词： black hole Hawking temperature tunneling radiation Lorentz-violating fermion

Strong cosmic censorship for a scalar field in an Einstein-Maxwell-Gauss-Bonnet-de Sitter black hole

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Chinese Physics C 2021年第2期45卷 555-567页

作者：甘庆雨王鹏伍厚文杨海棠 Center for Theoretical Physics College of PhysicsSichuan UniversityChengdu 610064China

It has been shown that the Christodoulou version of the strong cosmic censorship(SCC)conjecture can be violated for a scalar field in a near-extremal Reissner-Nordstrom-de Sitter black hole.In this paper,we investigate the effects of higher derivative corrections to the Einstein-Hilbert action on the validity of SCC,by considering a neutral massless scalar perturbation in 5 -and 6 -dimensional Einstein-Maxwell-Gauss-Bonnet-de Sitter black holes.Our numerical results show that the higher derivative term plays a different role in the d=5 case than it does in the d=6 case.For d=5 ,the SCC violation region increases as the strength of the higher derivative term increases.For d=6 ,the SCC violation region first increases and then decreases as the higher derivative correction becomes stronger,and SCC can always be restored for a black hole with a fixed charge ratio when the higher derivative correction is strong enough.Finally,we find that the C^(2) version of SCC is respected in the d=6 case,but can be violated in some near-extremal regimes in the d=5 case.

关键词： strong cosmic censorship black hole quasinormal mode

Entropy of higher-dimensional charged Gauss–Bonnet black hole in de Sitter space

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Communications in Theoretical Physics 2020年第8期72卷 119-125页

作者： Xiong-Ying Guo Huai-Fan Li Li-Chun Zhang Ren Zhao Department of Physics Shanxi Datong UniversityDatong 037009China Institute of Theoretical Physics Shanxi Datong UniversityDatong 037009China

The fundamental equation of the thermodynamic system gives the relation between the internal energy, entropy and volume of two adjacent equilibrium states. Taking a higher-dimensional charged Gauss–Bonnet black hole in de Sitter space as a thermodynamic system, the state parameters have to meet the fundamental equation of thermodynamics. We introduce the effective thermodynamic quantities to describe the black hole in de Sitter space. Considering that in the lukewarm case the temperature of the black hole horizon is equal to that of the cosmological horizon, we conjecture that the effective temperature has the same value. In this way, we can obtain the entropy formula of spacetime by solving the differential equation. We find that the total entropy contains an extra term besides the sum of the entropies of the two horizons. The corrected term of the entropy is a function of the ratio of the black hole horizon radius to the cosmological horizon radius, and is independent of the charge of the spacetime.

关键词： entropy Gauss–Bonnet gravity black hole de Sitter space