Thermodynamics and weak cosmic censorship conjecture of charged AdS black hole in the Rastall gravity with pressure

Treating the cosmological constant as a dynamical variable,we investigate the thermodynamics and weak cosmic censorship conjecture(WCCC)of a charged AdS black hole(BH)in the Rastall gravity.We determine the energy momentum relation of charged fermion at the horizon of the BH using the Dirac equation.Based on this relation,it is shown that the first law of thermodynamics still holds as a fermion is absorbed by the BH.However,the entropy of both the extremal and near-extremal BH decreases in the irreversible process,which means that the second law of thermodynamics is violated.Furthermore,we verify the validity of the WCCC by the minimum values of the metric function h(r)at its final state.For the extremal charged AdS BH in the Rastall gravity,we find that the WCCC is always valid since the BH is extreme.While for the case of near-extremal BH,we find that the WCCC could be violable in the extended phase space(EPS),depending on the value of the parameters of the BH and their variations.

Weak cosmic censorship conjecture in BTZ black holes with scalar fields

The weak cosmic censorship conjecture in the near-extremal BTZ black hole has been tested using test particles and fields.It has been claimed that such a black hole can be overspun.In this paper,we review the thermodynamics and weak cosmic censorship conjecture in BTZ black holes using the scattering of a scalar field.The first law of thermodynamics in the non-extremal BTZ black hole is recovered.For the extremal and near-extremal black holes,due to the divergence of the variation of entropy,we test the weak cosmic censorship conjecture by evaluating the minimum of the function f,and find that both the extremal and near-extremal black holes cannot be overspun.

Thermodynamics and weak cosmic censorship conjecture in Born-Infeld-anti-de Sitter black holes

In this study,we examine the laws of thermodynamics and the weak cosmic censorship conjecture in the normal and extended phase spaces of Born-Infeld-anti-de Sitter black holes by considering a charged particle absorption.In the normal phase space,the first and second laws of thermodynamics as well as the weak cosmic censorship are still valid.However,in the extended phase space,the second law of thermodynamics is violated for double-horizon black holes and part of single-horizon black holes.The first law of thermodynamics and the weak cosmic censorship conjecture are still valid for all types of black holes.In addition,we found that the shift of the metric function,which determines the locations of the horizons,takes the same form at the minimum point in both the normal and extended phase spaces,indicating that the weak cosmic censorship conjecture is independent of the thermodynamic phase space.

The Reissner-Nordström black hole surrounded by quintessence may not be destroyed

In the study of weak cosmic censorship conjectures(WCCC),some research finds that the Reissner-Nordström black hole might be destroyed by a test particle with particular mass and charge under some conditions,which means that the naked singularity of the black hole could be observed.This is not allowed in WCCC.We have never observed such naked singularities which should not exist in theory,so we need to find a proper way to protect the black hole from being destroyed by such particles.In this paper,we study a Reissner-Nordström black hole that is surrounded by quintessence(RN-Q)and find that the black hole would be stable and safe because of the effective potential barrier induced by the quintessence term.This result may also show in a sense that the quintessence might have more potential value.

Preliminary analyses of the dynamics and thermodynamics of rotating regular black holes

We investigate the dynamic and thermodynamic laws governing rotating regular black holes.By analyzing dynamic properties,i.e.,the interaction between scalar particles and rotating regular black holes,we establish the criteria that determine whether such black holes satisfy the laws of thermodynamics.In addition,we provide the general form of conserved quantities related to rotating regular black holes,including the relevant flows associated with neutral scalar particles.Meanwhile,we reexamine the relationship between the third law of thermodynamics and weak cosmic censorship conjecture for rotating regular black holes.Based on the abovementioned criteria,we discuss the laws of thermodynamics for three models of rotating regular black holes:Rotating Hayward black holes,Kerr black-bounce solutions,and loop quantum gravity black holes.Our findings indicate that none of the three models satisfies the first law of thermodynamics.In particular,the first and third models fail to comply with the three laws of thermodynamics,whereas the second model satisfies only the second and third laws of thermodynamics.Finally,we attempt to rescue the laws of thermodynamics by modifying entropy or extending the phase space.However,the two scenarios cannot ensure the three laws of thermodynamics in the three models,which reveals an unusual property of rotating regular black holes.

Overcharging a Reissner-Nordström Taub-NUT regular black hole

The destruction of a regular black hole event horizon might provide us the possibility to access regions inside black hole event horizon.This paper investigates the possibility of overcharging a charged Taub-NUT regular black hole via the scattering of a charged field and the absorption of a charged particle.For the charged scalar field scattering,both the near-extremal and extremal charged Taub-NUT regular black holes cannot be overcharged.For the test charged particle absorption,the result shows that the event horizon of the extremal charged Taub-NUT regular black hole still exists while the event horizon of the near-extremal one can be destroyed.However,if the charge and energy cross the event horizon in a continuous path,the near-extremal charged Taub-NUT regular black hole might not be overcharged.