A complementarity hypothesis concerning outsider and insider perspectives of a gargantuan black hole is proposed. The two thought experiments presented herein are followed by a brief discussion of a new interpretation...A complementarity hypothesis concerning outsider and insider perspectives of a gargantuan black hole is proposed. The two thought experiments presented herein are followed by a brief discussion of a new interpretation of black hole interior “space-and-time-reversal”. Specifically, it is proposed that the “singularity” space of the black hole interior is time-like and the expansion time of the black hole interior is space-like. The resemblance of this new insider interpretation to our own expanding and redshifting big bang universe is compelling.展开更多
The stability of the Schwarzschild black hole is restudied in the Painlevé coordinates. Using the Painlevé time coordinate to define the initial time, we reconsider the odd perturbation and find that the Sch...The stability of the Schwarzschild black hole is restudied in the Painlevé coordinates. Using the Painlevé time coordinate to define the initial time, we reconsider the odd perturbation and find that the Schwarzschild black hole in the Painlevé coordinates is unstable. The Painlevé metric in this paper corresponds to the white-hole-connected region of the Schwarzschild black hole （r 〉 2m） and the odd perturbation may be regarded as the angular perturbation. Therefore, the white-hole-connected region of the Schwarzschild black hole is unstable with respect to the rotating perturbation.展开更多
We analyze the Sehrodinger-type scalar wave equation of an extended black hole in f（R） gravity, and numerically investigate its absorption/scattering cross sections using the partial wave method. It is found that th...We analyze the Sehrodinger-type scalar wave equation of an extended black hole in f（R） gravity, and numerically investigate its absorption/scattering cross sections using the partial wave method. It is found that the dimension of length a makes the peak value of the effective scattering potential fall down, and the absorption cross section oscillates around the geometric optical value in the high frequency regime. We can also see that the scattering flux becomes stronger and its angle width becomes narrower in the forward direction, the glory peak becomes lower and the glory width becomes narrower along the backward direction when the coupling parameter α increases.展开更多
In this paper, we study the gravitational quasi-normal modes（QNMs） for a static R^2 black hole（BH） in Anti-de Sitter（AdS） spacetime. The corresponding master equation of odd parity is derived and the QNMs are ev...In this paper, we study the gravitational quasi-normal modes（QNMs） for a static R^2 black hole（BH） in Anti-de Sitter（AdS） spacetime. The corresponding master equation of odd parity is derived and the QNMs are evaluated by the Horowitz and Hubeny method. Meanwhile the stability of such BH is also discussed through the temporal evolution of the perturbation field. Here we mainly consider the coefficient λ, which is related to the radius of AdS black hole, on the QNMs of the R^2 AdS BH. The results show that the Re（ω） and ｜Im（ω）｜ of the QNMs increase together as ｜λ｜ increases for a given angular momentum number l. That indicates with a larger value of ｜λ｜ the corresponding R^2 AdS BH returns to stable much more quickly. The dynamic evolution of the perturbation field is consistent with the results derived by the Horowitz and Hubeny method. Since in the conformal field theory the QNMs can reflect its approach to equilibrium, so our related results could be referential to studies of the AdS/CFT conjecture. The relationship between λ and the properties of the static R^2 BH might be helpful for the development of R^2 gravitational theory.展开更多
In this work, we re-assess a class of black hole solutions in a global monopole spacetime in the framework of an f(R)-gravity model. Our main line of investigation consists in considering a region close enough to the ...In this work, we re-assess a class of black hole solutions in a global monopole spacetime in the framework of an f(R)-gravity model. Our main line of investigation consists in considering a region close enough to the black hole, but such that the weak field approximation is still valid. The stability of the black hole is studied in terms of its thermodynamical properties, with the radial coordinate written as a power-law function with the status of the main factor underneath the stability of the model. We obtain the explicit expressions for the thermodynamical quantities of the black hole as functions of the event horizon, by considering both the Hawking and the local temperatures. The phase transitions that may occur in this system, including the Hawking-Page phase transition, are inspected with particular attention. We work out and contemplate a solution of special interest in which one of the parameters is related to the cosmological constant. Our main result sets out to establish a comparison between both the Hawking and the local formalisms for the black hole in the framework of the f(R)-gravity in the particular space-time adopted here.展开更多
We study the particle dynamics around a black hole(BH)in f(Q)gravity.First,we investigate the influence of the parameters of f(Q)gravity on the horizon structure of the BH,photon orbits and the radius of the innermost...We study the particle dynamics around a black hole(BH)in f(Q)gravity.First,we investigate the influence of the parameters of f(Q)gravity on the horizon structure of the BH,photon orbits and the radius of the innermost stable circular orbit(ISCO)of massive particles.We further study the effects of the parameters of f(Q)gravity on the shadow cast by the BH.Moreover,we consider weak gravitational lensing using the general method,where we also explore the deflection angle of light rays around the BH in f(Q)gravity in uniform and nonuniform plasma mediums.展开更多
Based on the 4-dimensional black hole solution of f(R) theory coupled to a nonlinear Maxwell field, we calculate the interior volume of a charged f(R) black hole using the method proposed by Christodoulou and Rovelli....Based on the 4-dimensional black hole solution of f(R) theory coupled to a nonlinear Maxwell field, we calculate the interior volume of a charged f(R) black hole using the method proposed by Christodoulou and Rovelli.Considering massless scalar field in the interior volume and Hawking radiation carrying only energy, we calculate the entropy of the scalar field inside a charged f(R) black hole and investigate the evolution of the entropy under Hawking radiation. In the meantime, the evolution of the Bekenstein-Hawking entropy under Hawking radiation has also been calculated. Based on these results, the proportional relation is obtained between the evolution of the scalar field entropy and the evolution of Bekenstein-Hawking entropy under Hawking radiation. According to the result, we investigate and discuss how the modified coefficient b in f(R) gravity theory affects the evolution relation between the two types of entropy. It is shown that the radiation rate for Hawking radiation of a charged f(R) black hole can increase with the modified coefficient b.展开更多
We consider the evolution of a black hole involving an f(R)global monopole based on the Extended Uncertainty Principle(EUP).The black hole evolutions refer to the instability due to the Parikh-Kraus-Wilczeck tunneling...We consider the evolution of a black hole involving an f(R)global monopole based on the Extended Uncertainty Principle(EUP).The black hole evolutions refer to the instability due to the Parikh-Kraus-Wilczeck tunneling radiation or fragmentation.It is found that the EUP corrections make the entropy difference larger to encourage the black hole to radiate more significantly.We also show that the appearance of the EUP effects results in the black hole’s division.The influence from the global monopole and the revision of general relativity can also adjust the black hole evolution simultaneously but cannot change the final result that the black hole will not be stable because of the EUP’s effects.展开更多
Quasinormal modes （QNMs） for Dirac perturbations off（R） black holes （BHs） are described in this paper, involving two types of f（R） solution： f（R） （Sehwarzschild） BHs and f（R） （Maxwell） BHs. With the f...Quasinormal modes （QNMs） for Dirac perturbations off（R） black holes （BHs） are described in this paper, involving two types of f（R） solution： f（R） （Sehwarzschild） BHs and f（R） （Maxwell） BHs. With the finite difference method, the stability of the f（R） black holes （BHs） is analysed and the threshold range off（R） （Schwarzschild） BHs and f（R） （Maxwell） BHs is defined respectively. The results show that due to the presence of the correction factor Ro, the damping rate of Dirac field decreases. Meanwhile, the influence of angular quantum number values [k] on the f（R） BHs is investigated. The results indicate that the QNMs oscillation becomes tenser and damping speed slowly decreases with ]k[ increasing. Furthermore, under the Dirac perturbation, the stability off（R） solutions can be reflected in the manner of Dirac QNMs. The relationships between the QNMs and the parameters （]k], charge Q and mass m） are discussed in massless, and massive cases, by contrast to the classical BHs.展开更多
The thermodynamic behavior of field equations for the generalized f(R) gravity with arbitrary coupling between matter and geometry is studied in the two kinds of spacetime,i.e.,the both spatially homogenous,isotropic ...The thermodynamic behavior of field equations for the generalized f(R) gravity with arbitrary coupling between matter and geometry is studied in the two kinds of spacetime,i.e.,the both spatially homogenous,isotropic FRW universe and static,spherically symmetric black hole spacetime.The field equations of the generalized f(R) gravity with arbitrary coupling between matter and geometry can be cast to the form of the first law of thermodynamics with the reputed entropy production terms dS,which are quite general and can degenerate to the cases of Einstein's general relativity and pure f(R) gravity with non-coupling and nonminimal coupling as special cases.The appearance of the entropy production term dS illustrates that the horizon thermodynamics is non-equilibrium one for the generalized f(R) gravity with arbitrary coupling between matter and geometry.展开更多
文摘A complementarity hypothesis concerning outsider and insider perspectives of a gargantuan black hole is proposed. The two thought experiments presented herein are followed by a brief discussion of a new interpretation of black hole interior “space-and-time-reversal”. Specifically, it is proposed that the “singularity” space of the black hole interior is time-like and the expansion time of the black hole interior is space-like. The resemblance of this new insider interpretation to our own expanding and redshifting big bang universe is compelling.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 10475013, 10373003 and 10375087）, the National Basic Research Program （Grant No 2004CB318000） and the Post-Doctor Foundation of China.
文摘The stability of the Schwarzschild black hole is restudied in the Painlevé coordinates. Using the Painlevé time coordinate to define the initial time, we reconsider the odd perturbation and find that the Schwarzschild black hole in the Painlevé coordinates is unstable. The Painlevé metric in this paper corresponds to the white-hole-connected region of the Schwarzschild black hole （r 〉 2m） and the odd perturbation may be regarded as the angular perturbation. Therefore, the white-hole-connected region of the Schwarzschild black hole is unstable with respect to the rotating perturbation.
基金Supported by the National Natural Science Foundation of China under Grant No 10873004the National Basic Research Program of China under Grant No 2010CB832803the Program for Changjiang Scholars and Innovative Research Team in University under Grant No IRT0964
文摘We analyze the Sehrodinger-type scalar wave equation of an extended black hole in f（R） gravity, and numerically investigate its absorption/scattering cross sections using the partial wave method. It is found that the dimension of length a makes the peak value of the effective scattering potential fall down, and the absorption cross section oscillates around the geometric optical value in the high frequency regime. We can also see that the scattering flux becomes stronger and its angle width becomes narrower in the forward direction, the glory peak becomes lower and the glory width becomes narrower along the backward direction when the coupling parameter α increases.
基金supported by the National Natural Science Foundation of China(Grant Nos.11205254,11178018,11375279,and 11605015)the Fundamental Research Funds for the Central Universities,China(Grant Nos.106112016CDJXY300002 and CDJRC10300003)+1 种基金the Chinese State Scholarship Fund,FAPESP(Grant No.2012/08934-0)the Natural Science Foundation Project of CQ CSTC(Grant No.2011BB0052)
文摘In this paper, we study the gravitational quasi-normal modes（QNMs） for a static R^2 black hole（BH） in Anti-de Sitter（AdS） spacetime. The corresponding master equation of odd parity is derived and the QNMs are evaluated by the Horowitz and Hubeny method. Meanwhile the stability of such BH is also discussed through the temporal evolution of the perturbation field. Here we mainly consider the coefficient λ, which is related to the radius of AdS black hole, on the QNMs of the R^2 AdS BH. The results show that the Re（ω） and ｜Im（ω）｜ of the QNMs increase together as ｜λ｜ increases for a given angular momentum number l. That indicates with a larger value of ｜λ｜ the corresponding R^2 AdS BH returns to stable much more quickly. The dynamic evolution of the perturbation field is consistent with the results derived by the Horowitz and Hubeny method. Since in the conformal field theory the QNMs can reflect its approach to equilibrium, so our related results could be referential to studies of the AdS/CFT conjecture. The relationship between λ and the properties of the static R^2 BH might be helpful for the development of R^2 gravitational theory.
基金CNPq-Brasil for his MSc Fellowship at the Instituto de Fsica of Universidade Federal Fluminense
文摘In this work, we re-assess a class of black hole solutions in a global monopole spacetime in the framework of an f(R)-gravity model. Our main line of investigation consists in considering a region close enough to the black hole, but such that the weak field approximation is still valid. The stability of the black hole is studied in terms of its thermodynamical properties, with the radial coordinate written as a power-law function with the status of the main factor underneath the stability of the model. We obtain the explicit expressions for the thermodynamical quantities of the black hole as functions of the event horizon, by considering both the Hawking and the local temperatures. The phase transitions that may occur in this system, including the Hawking-Page phase transition, are inspected with particular attention. We work out and contemplate a solution of special interest in which one of the parameters is related to the cosmological constant. Our main result sets out to establish a comparison between both the Hawking and the local formalisms for the black hole in the framework of the f(R)-gravity in the particular space-time adopted here.
基金funded by the National Natural Science Foundation of China 11975145partly supported by Research Grant FZ-20200929344 and F-FA2021-510 of the Uzbekistan Ministry for Innovative DevelopmentGrant No.ZC304022919 to support his Postdoctoral Fellowship at Zhejiang Normal University
文摘We study the particle dynamics around a black hole(BH)in f(Q)gravity.First,we investigate the influence of the parameters of f(Q)gravity on the horizon structure of the BH,photon orbits and the radius of the innermost stable circular orbit(ISCO)of massive particles.We further study the effects of the parameters of f(Q)gravity on the shadow cast by the BH.Moreover,we consider weak gravitational lensing using the general method,where we also explore the deflection angle of light rays around the BH in f(Q)gravity in uniform and nonuniform plasma mediums.
基金Supported by the National Natural Science Foundation of China under Grant No.11235003
文摘Based on the 4-dimensional black hole solution of f(R) theory coupled to a nonlinear Maxwell field, we calculate the interior volume of a charged f(R) black hole using the method proposed by Christodoulou and Rovelli.Considering massless scalar field in the interior volume and Hawking radiation carrying only energy, we calculate the entropy of the scalar field inside a charged f(R) black hole and investigate the evolution of the entropy under Hawking radiation. In the meantime, the evolution of the Bekenstein-Hawking entropy under Hawking radiation has also been calculated. Based on these results, the proportional relation is obtained between the evolution of the scalar field entropy and the evolution of Bekenstein-Hawking entropy under Hawking radiation. According to the result, we investigate and discuss how the modified coefficient b in f(R) gravity theory affects the evolution relation between the two types of entropy. It is shown that the radiation rate for Hawking radiation of a charged f(R) black hole can increase with the modified coefficient b.
基金Supported by the National Natural Science Foundation of China(NSFC)(10875043)。
文摘We consider the evolution of a black hole involving an f(R)global monopole based on the Extended Uncertainty Principle(EUP).The black hole evolutions refer to the instability due to the Parikh-Kraus-Wilczeck tunneling radiation or fragmentation.It is found that the EUP corrections make the entropy difference larger to encourage the black hole to radiate more significantly.We also show that the appearance of the EUP effects results in the black hole’s division.The influence from the global monopole and the revision of general relativity can also adjust the black hole evolution simultaneously but cannot change the final result that the black hole will not be stable because of the EUP’s effects.
基金Supported by FAPESP No.2012/08934-0National Natural Science Foundation of China under Grant Nos.11205254,11178018,11375279,11605015+1 种基金the Natural Science Foundation Project of CQ CSTC 2011BB0052the Fundamental Research Funds for the Central Universities 106112016CDJXY300002 and CDJRC10300003
文摘Quasinormal modes （QNMs） for Dirac perturbations off（R） black holes （BHs） are described in this paper, involving two types of f（R） solution： f（R） （Sehwarzschild） BHs and f（R） （Maxwell） BHs. With the finite difference method, the stability of the f（R） black holes （BHs） is analysed and the threshold range off（R） （Schwarzschild） BHs and f（R） （Maxwell） BHs is defined respectively. The results show that due to the presence of the correction factor Ro, the damping rate of Dirac field decreases. Meanwhile, the influence of angular quantum number values [k] on the f（R） BHs is investigated. The results indicate that the QNMs oscillation becomes tenser and damping speed slowly decreases with ]k[ increasing. Furthermore, under the Dirac perturbation, the stability off（R） solutions can be reflected in the manner of Dirac QNMs. The relationships between the QNMs and the parameters （]k], charge Q and mass m） are discussed in massless, and massive cases, by contrast to the classical BHs.
基金supported by the National Natural Science Foundation of China(Grant Nos.11175077 and 11147150)the Natural Science Foundation of Liaoning Province(Grant Nos.20102124 and L2011189)
文摘The thermodynamic behavior of field equations for the generalized f(R) gravity with arbitrary coupling between matter and geometry is studied in the two kinds of spacetime,i.e.,the both spatially homogenous,isotropic FRW universe and static,spherically symmetric black hole spacetime.The field equations of the generalized f(R) gravity with arbitrary coupling between matter and geometry can be cast to the form of the first law of thermodynamics with the reputed entropy production terms dS,which are quite general and can degenerate to the cases of Einstein's general relativity and pure f(R) gravity with non-coupling and nonminimal coupling as special cases.The appearance of the entropy production term dS illustrates that the horizon thermodynamics is non-equilibrium one for the generalized f(R) gravity with arbitrary coupling between matter and geometry.
