Recently, numerous investigations have revealed that AdS black holes exhibit fundamental characteristics similar to those of ordinary thermodynamic systems. The thermodynamic properties of multi-horizon spacetimes with different Hawking temperatures have garnered significant attention. In this paper, we regard the Reissner-Nordstrom-de Sitter black hole with quintessence (RN-dSQ black hole) as an equivalent thermodynamic system and firstly provide the effective thermodynamic quantities of RN-dSQ spacetime. Then, the heat capacity of the RN-dSQ spacetime with coexistence of two horizons described by effective thermodynamic quantities is discussed. The results indicate that for the RN-dSQ black hole system with the coexistence of two horizons, the variation curves of the heat capacity with the effective temperature and ratio of two horizons possess characteristics similar to the paramagnetic system. Additionally, the RN-dSQ spacetime can be regard as an ordinary two-level quantum system in which the particles locate at different horizons with different energies. Assuming that the heat capacity of RN-dSQ spacetime is primarily contributed by microscopic particles located between the two horizons. By comparison, the number of microscopic particles in RN-dSQ spacetime is obtained, which just reflects the quantum properties of dS spacetime.

China

Xiong Ying Guo

Huai-Fan Li

Yun-Zhi Du

Wen-Qi Wang

Ren Zhao

The thermodynamic properties of Reissner-Nordstrom-de sitter black hole with quintessence

In this paper, we examined the motion of a spinning particle around a Reissner-Nordström-like black hole. Initially, we analyze the dynamics of the spinning test particles using the Mathisson–Papapetrou–Dixon equation. Subsequently, we derive the effective potential and examine it for the parameter of the Reissner-Nordström-like black hole. We then examine the impact of the particle’s spin on the innermost stable circular orbits (ISCO), specific angular momentum, and energy at ISCO for different parameters of hairy black holes. Furthermore, we determine the critical values of the particle’s spin <math altimg='si6.svg'><mi>s</mi></math>, above which time-like particles become non-physical and space-like. Furthermore, we plot and discuss the variation of the critical spin values for different values of <math altimg='si2.svg'><mi>l</mi></math> and charge <math altimg='si3.svg'><mi>Q</mi></math>. Additionally, particle trajectories near a Reissner-Nordstr&#246;m-like (RN-like) black hole are examined for different spacetime and particle parameters. In conclusion, we analyze the center-of-mass of two spinning particles colliding near the boundary of the hairy black hole.

Uzbekistan

Gulnisa Abdukayumova

Azerbaijan

Farruh Atamurotov

Ahmadjon Abdujabbarov

Thailand

Phongpichit Channuie

G. Mustafa

Dynamics of spinning particles around the Reissner-Nordstrom-like black hole

In this study, we investigate the Weak Gravity Conjecture (WGC) in the context of quantum-corrected Reissner–Nordstrom–AdS (RN-AdS) black holes within Kiselev spacetime. Our focus is on photon spheres, which serve as markers for stable and unstable photon spheres. We confirm the validity of the WGC by demonstrating that quantum corrections do not alter the essential charge-to-mass ratio, thereby supporting the conjecture’s universality. Our analysis reveals that black holes with a charge greater than their mass $$(Q > M)$$ possess photon spheres or exhibit a total topological charge of the photon sphere $$(\text {PS} = -1),$$ which upholds the WGC. This finding is significant as it reinforces the conjecture’s applicability even in the presence of quantum corrections. Furthermore, we examine various parameter configurations to understand their impact on the WGC. Specifically, we find that configurations with $$\omega = -\frac{1}{3}$$ and $$\omega = -1$$ maintain the conjecture, indicating that these values do not disrupt the charge-to-mass ratio required by the WGC. However, for $$\omega = -\frac{4}{3},$$ the conjecture does not hold, suggesting that this particular parameter value leads to deviations from the expected behavior. These results open new directions for research in quantum gravity, as they highlight the importance of specific parameter values in maintaining the WGC. The findings suggest that while the WGC is robust under certain conditions, there are scenarios where it may be challenged, prompting further investigation into the underlying principles of quantum gravity.

Iran

Mohammad Alipour

Canada

Mohammad S. Afshar

Saeed Noori Gashti

Jafar Sadeghi

Weak gravity conjecture validation with photon spheres of quantum corrected Reissner–Nordstrom–AdS black holes in Kiselev spacetime

We investigate the pair production near a (near) extremal magnetized Reissner-Nordstrom black hole. The pair production is shown to exist in the extremal state, which can be interpreted as the Schwinger effect due to the strong field under consideration. To show a correspondence between the growth of the external magnetic field and the scalar absorption, some numerical examples are provided.

Indonesia

Haryanto M. Siahaan

Spontaneous pair production near magnetized Reissner-Nordstrom black holes

The superradiant stability of higher dimensional non-extremal Reissner-Nordstrom black hole under charged massive scalar perturbation is analytically studied. We extend our previous studies of four- and five-dimensional non-extremal Reissner-Nordstrom black hole cases to six-dimensional case. By analyzing the derivative of the effective potential with an analytical method, we find that no potential well exists outside the outer horizon of the black hole for the superradiant scalar modes. This means that there is no black hole bomb for the system consisting of six-dimensional Reissner-Nordstrom black hole and charged massive scalar perturbation and the system is superradiantly stable.

Run-Dong Zhao

Jia-Hui Huang

Six-dimensional non-extremal Reissner-Nordstrom black hole, charged massive scalar perturbation and black hole bomb

The superradiant stability of asymptotically flat D-dimensional extremal Reissner–Nordstrom black holes under charged massive scalar perturbation is analytically studied. Recently, an analytical method has been proposed by the author and used to prove that five and six-dimensional extremal Reissner–Nordstrom black holes are superradiantly stable under charged massive scalar perturbation. We apply this analytical method in the D-dimensional extremal Reissner–Nordstrom black hole case and prove that there is no black hole bomb for D-dimensional Reissner–Nordstrom black hole under charged massive scalar perturbation and the system is superradiantly stable.

No black hole bomb for D-dimensional extremal Reissner–Nordstrom black holes under charged massive scalar perturbation

We revisit the superradiant stability of five and six-dimensional extremal Reissner–Nordstrom black holes under charged massive scalar perturbation with a new analytical method. In each case, it is analytically proved that the effective potential experienced by the scalar perturbation has only one maximum outside the black hole horizon and no potential well exists for the superradiance modes. So the five and six-dimensional extremal Reissner–Nordstrom black holes are superradiantly stable. The new method we developed is based on the Descartes’ rule of signs for the polynomial equations. Our result provides a complementary support of previous studies on the stability of higher dimensional extremal Reissner–Nordstrom black holes based on numerical methods.

Tian-Tian Cao

Mu-Zi Zhang

Superradiant stability of five and six-dimensional extremal Reissner–Nordstrom black holes

The superradiant stability of asymptotically flat higher dimensional non-extremal Reissner-Nordstrom black holes under charged massive scalar perturbation is analytically studied. We extend an analytical method developed by one of the authors in the extremal Reissner-Nordstrom black hole cases to non-extremal cases. Using the new analytical method, we revisit four-dimensional Reissner-Nordstrom black hole case and obtain that four-dimensional Reissner-Nordstrom black hole is superradiantly stable, which is consistent with results in previous works. We then analytically prove that the five-dimensional Reissner-Nordstrom black holes are also superradiantly stable under charged massive scalar perturbation. Our result implies that all higher dimensional non-extremal Reissner-Nordstrom black holes may be superradiantly stable under charged massive scalar perturbation.

Yi-Feng Zou

Higher-dimensional non-extremal Reissner-Nordstrom black holes, scalar perturbation and superradiance: An analytical study

Black holes immersed in magnetic fields are believed to be important systems in astrophysics. One interesting topic on these systems is their superradiant stability property. In the present paper, we analytically obtain the superradiantly stable regime for the asymptotically flat dyonic Reissner–Nordstrom black holes with charged massive scalar perturbation. The effective potential experienced by the scalar perturbation in the dyonic black hole background is obtained and analyzed. It is found that the dyonic black hole is superradiantly stable in the regime  $$0&lt;r_{-}/r_{+}&lt;2/3$$  <math> <mrow> <mn>0</mn> <mo>&lt;</mo> <msub> <mi>r</mi> <mo>-</mo> </msub> <mo>/</mo> <msub> <mi>r</mi> <mo>+</mo> </msub> <mo>&lt;</mo> <mn>2</mn> <mo>/</mo> <mn>3</mn> </mrow> </math>  , where  $$r_\pm $$  <math> <msub> <mi>r</mi> <mo>±</mo> </msub> </math>   are the event horizons of the dyonic black hole. Compared with the purely electrically charged Reissner–Nordstrom black hole case, our result indicates that the additional coupling of the charged scalar perturbation with the magnetic filed makes the black hole and scalar perturbation system more superradiantly unstable, which provides further evidence on the instability induced by magnetic field in black hole superradiance process.

Jun-Huai Xu

Zhan-Feng Mai

Dyonic Reissner–Nordstrom black holes and superradiant stability

We present a novel solution describing magnetized spacetime outside an electrically charged massive object equipped with NUT parameter. To get the solution, we employ the Ernst magnetization to the Reissner–Nordstrom–Taub–NUT spacetime as the seed. After discussing some physical aspects of the spacetime, we show that the extremal entropy of a magnetized Reissner–Nordstrom–Taub–NUT black hole can be reproduced by using the Cardy formula.

Haryanto Siahaan

Magnetized Reissner–Nordstrom–Taub–NUT spacetime and microscopic entropy