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.

de Rham-Gabadadze-Tolley(dRGT)黑洞的热力学与弱宇宙监督假设

有质量引力理论作为修正引力理论之一,对探究宇宙加速膨胀,以及解释暗能量和暗物质问题等有重要意义.本文研究了在常规相空间中de Rham-Gabadadze-Tolley(dRGT)有质量引力下球对称黑洞的热力学第一定律、热力学第二定律与弱宇宙监督假设是否成立;并通过图像探究熵的微分变化量随事件视界r_(d)变化的影响,以及与dRGT黑洞无量纲自由参数α,β与引力子质量对该图像的影响.在研究过程中,通过引入标量粒子的能量G动量关系,来验证黑洞热力学第一定律是否成立,通过观察事件视界对熵的微分变化量的影响,来验证黑洞热力学第二定律是否成立.研究发现,黑洞在吸收粒子的同时,其视界半径始终存在,从而使奇点始终没有裸露出来.结果表明,在dRGT有质量引力下球对称黑洞的热力学第一定律,热力学第二定律与弱宇宙监督假设均成立.

Flat Space Cosmology as a Model of Penrose’s Weyl Curvature Hypothesis and Gravitational Entropy

FSC is shown to be an excellent model of Penrose’s Weyl curvature hypothesis and his concept of gravitational entropy. The assumptions of FSC allow for the minimum entropy at the inception of the cosmic expansion and rigorously define a cosmological arrow of time. This is in sharp contrast to inflationary models, which appear to violate the second law of thermodynamics within the early universe. Furthermore, by virtue of the same physical assumptions applying at any cosmic time t, the perpetually-flat FSC model predicts the degree of scale invariance observed in the CMB anisotropy pattern, without requiring an explosive and exceedingly brief inflationary epoch. Penrose’s concepts, as described in this paper, provide support for the idea that FSC models gravitational entropy and Verlinde’s emergent gravity theory.

Strong Cosmic Censorship in accelerating spacetime

It has been established that Strong Cosmic Censorship Conjecture(SCCC)is respected by an asymptotically flat black hole with charge,but violated by a charged asymptotically de Sitter black hole.We studied the instability of the Cauchy horizon for an accelerating black hole in Einstein theory conformally coupled with a scalar field.The black hole is uncharged while having inner,outer,and acceleration horizons.In the limit of vanishing acceleration,denoted by A→0,it becomes asymptotically flat and extremal,with its acceleration horizon vanishing as well.By exploring the perturbation of the massless scalar field upon the accelerating black hole,whose decay rate is governed by the quasinormal mode spectra,we show that the SCCC is violated in the near-extremal regime and also in the A→0+limit.Our result is the first observation of a black hole violating the SCCC in an almost asymptotically Minkowskian flat regime,as well as the first example of a black hole violating the SCCC with neither charge nor rotation.

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.

Modified White Hole Enthalpy Coupled to Quantum Bose-Einstein Condensate at Extremely Low Entropy

We model the universe as a white hole, and in the process we perform detailed analysis of the enthalpy equation of the modified white hole, and we get a much detailed picture of when and how did;quantum gravity (cosmology) phase, inflationary phase, and the acceleration phase of the universe happened. We determine the field equations of the modified white hole and evolve the scale factor and compare the evolution to the thermodynamic properties of the universe. We also illustrate that the strong energy condition is violated, but both the null energy condition and the strong cosmic censorship are not violated. Lastly, we couple the enthalpy to the Bose-Einstein condensate at extremely low entropy at the quantum gravity (cosmology) regime. Thereafter, we determine the unstable condition of the Bose-Einstein quantum equation which we interpret as the moment when the big bang occurred.

三谈《周髀算经》中的盖天说

本文同迄今为止的流行观点相反,认为盖天说比浑天说先进。这是因为:盖天说已经识破天地相连的假象,发现天地相互平行,因而有利于发展地圆观点;已经知道天上和地面上都有北极、赤道和南北回归线,因而有条件提出地理地带的概念;已经发现地面分为白昼区和黑夜区,并且力图解决白昼区的大小问题,凡此都先进于浑天说。

彭罗斯对广义相对论和黑洞理论的贡献

这篇文章列出了2020年诺贝尔物理学奖获得者彭罗斯对广义相对论和黑洞理论做出的重要贡献.它包括著名的奇点定理、彭罗斯图、彭罗斯过程和宇宙监督假设等.介绍了彭罗斯和霍金之间的友谊和合作.也简要介绍了另两位2020年诺贝尔物理学奖获得者根泽尔和盖兹对存在于银河系中心的超大质量致密天体的发现.

客观运气学假说

在传统中医运气学理论的基础上,结合现代天文学的研究成果提出客观运气学的概念及假说:五运是地球公转轨道的客观规律和现象,六气是地球公转过程中的宇宙气流和大气环流作用现象,地球每年运行轨迹的不同是形成太过、不及的根本,地球公转轨迹遵循60年的循环规律;地球气候、气象、物候是由地球运行轨迹决定的;地球公转、宇宙气流对人体发病具有一定的影响;地球自转对人体和自然有一定的影响;瘟疫是宇宙特殊气流对地球万物的影响。随着时代的发展,人们对地球、自然的认识越来越深入,站在客观的角度来研究运气学说具有重要意义。

治疗—对照差的临床意义及其判别方法

目的 说明治疗—对照差的临床意义及其判别方法 ,为此提出一种非虚假设检验。方法 以同源有效样本量取代样本量 ,将用于比较两率差和最小临床承认疗效差量的经典非虚假设检验加以扩展以覆盖终检。结果 这种检验可用于实现这种判别。在无终检时 ,它还原为经典检验。结论 与通常的药物疗效评价方法相比 ,这显然提高了一步。

黑洞热力学第三定律与宇宙监督假设

对黑洞视界的研究结果表明 :黑洞热力学第三定律可禁止裸奇性的出现 ;反之 ,裸奇性的出现必破坏黑洞热力学第三定律。由此推断宇宙监督假设就是黑洞热力学第三定律。

电离层的掩星分离假设反演法

该文首先简要介绍了无线电掩星探测技术及其发展现状和传统Abel变换方法面临的问题。为改进传统Abel变换反演方法,利用电子密度廓线的分离假设,引进了分离假设反演法。随后利用国际电离层参考模式IRI2007给出1000个掩星事件截面的模拟数据及COSMIC卫星星座的一天实测数据,进行比较计算,并对结果进行了分析,验证了分离假设反演法的有效性。文中还给出了垂直电子总量VTEC(Vertical Total Electron Content)先验场的获取途径。最后,对分离假设反演法的进一步研究的方向进行了探讨。

Strong cosmic censorshiP for a scalar field in a logarithmic-de Sitter black hole

It has been shown that the quasinormal modes of perturebated fields can be used to investigate the validity of strong cosmic censorship(SCC).Relevant issues for Reissner-Nordstrom-de Sitter(RN-dS)black holes and Born-Infeld-de Sitter black holes have been discussed.In this paper,we investigate SCC in an asymptotic RN-dS black hole with logarithmic nonlinear electromagnetic field perturbed by massless scalar fields.It has been argued that SCC can be violated in a near-extremal RN-dS black hole.However,we find that the NLED effect can rescue SCC for a near-extremal logarithmic-de Sitter black hole.Compared with Born-Infeld model,we find that the NLED effect has similar behavior.

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.

Spratlies Archipelago as the Australasian Tektite Impact Crater, Details of Formation &Richard Muller’s Dust Cloud Explanation for the Mid-Pleistocene Ice Age Cycle Transition

Several significant events of a geological nature occurred approximately 800 ka before the present: (1) Australasian tektite fall (AA), (2) Brunhes-Matuyama geomagnetic reversal (BMR), (3) mid-Pleistocene changes in ice age cycles. Add to these the undated fault system (4) in the South-West (SW) of the South China Sea (SCS). Here we offer a unified cause for all four of these in (5), an impact in the SCS of a large, massive cosmic object, likely a comet, obliquely coming from the SW at an extremely shallow angle, striking the Sunda shelf yet unexploded with the shock of its compressed air bow wave, and causing the continual shelf and slope to collapse, resulting in the fault system (4), then traveling almost tangentially to the surface, exploding at impact with the sea surface, ejecting the tektites (1), creating the formation underlying the later atolls of Spratlies Archipelago (6), Nansha Islands in Chinese, & causing the BMR (2). An explanation of event (3) was Richard Muller’s hypothesis of planet Earth passing through an interplanetary dust cloud periodically due to ecliptic precession. Here we hypothesize this cloud actually is a belt of Australasian tektites ejected into space at super-orbital velocities that Earth encounters about every 100 ka.

Weak cosmic censorship conjecture and thermodynamics in quintessence Ad S black hole under charged particle absorption

Considering the cosmological constant as the pressure,this study addresses the laws of thermodynamics and weak cosmic censorship conjecture in the Reissner-Nordstrom-AdS black hole surrounded by quintessence dark energy under charged Particle absorption.The first law of thermodynamics i5 found to be valid as a Particle is absorbed by the black hole.The second law,however,is violated for the extremal and near-extremal black holes,because the entropy of these black hole decrease.Moreover,we find that the extremal black hole does not change its configuration in the extended phase space,implying that the weak cosmic censorship conjecture is valid.Remarkably,the near-extremal black hole can be overcharged beyond the extremal condition under charged particle absorption.Hence,the cosmic censorship conjecture could be violated for the near-extremal black hole in the extended phase space.For comparison,we also discuss the first law,second law,and the weak cosmic censorship conjecture in normal phase space,and find that all of them are valid in this case.

气本质研究—宇宙物质结构三层面理论假说

气学说是中华优秀传统文化和中医学的重要组成部分,气不只是一个哲学概念,而且是真实的客观存在。在现代科学、哲学的背景下,经过广泛收集材料和医学临证实践、气学内证体察实践中对气的真实性体悟,本文对气的本质(包括意识本质)进行了较为深入的探索研究,提出宇宙物质结构三层面理论(又称三层物质理论)假说,并就该假说的内涵、第三层面物质特征、基本观点、核心内容、技术支柱和实验验证等进行了提纲式的论述和深入的阐发。本文认为三层物质理论假说的研究意义重大,它不仅能揭示了气和意识的本质问题,还将可能引发新的科学革命。

Thermodynamics and weak cosmic censorship conjecture of BTZ black holes in extended phase space

As a charged fermion drops into a BTZ black hole, the laws of thermodynamics and the weak cosmic censorship conjecture are investigated in both the normal and extended phase space, where the cosmological parameter and renormalization length are regarded as extensive quantities. In the normal phase space, the first and second law of thermodynamics, and the weak cosmic censorship are found to be valid. In the extended phase space, although the first law and weak cosmic censorship conjecture remain valid, the second law is dependent on the variation of the renormalization energy dK. Moreover, in the extended phase space, the configurations of extremal and near-extremal black holes are not changed, as they are stable, while in the normal phase space, the extremal and near-extremal black holes evolve into non-extremal black holes.

Weak cosmic censorship conjecture in the nonlinear electrodynamics black hole under the charged scalar field

In this paper,we study the thermodynamics and the weak cosmic censorship conjecture of the nonlinear electrodynamics black hole under the scattering of a charged complex scalar field.According to the energy and charge fluxes of the scalar field,the variations of this black hole’s energy and charge can be calculated during an infinitesimal time interval.With scalar field scattering,the variation of the black hole is calculated in the extended and normal phase spaces.In the normal phase space,the cosmological constant and the normalization parameter are fixed,and the first and second laws of thermodynamics can also be satisfied.In the extended phase space,the cosmological constant and the normalization parameter are considered as thermodynamic variables,and the first law of thermodynamics is valid,but the second law of thermodynamics is not valid.Furthermore,the weak cosmic censorship conjecture is both valid in the extended and normal phase spaces.

Non-Spherical Gravitational Collapse of Strange Quark Matter

We study the non-spherical gravitational collapse of the strange quark null fluid. The interesting feature which emerges is that the non-spherical collapse of charged strange quark matter leads to a naked singularity whereas the gravitational collapse of neutral quark matter proceeds to form a black hole. We extend the earlier work of Harko and Cheng [Phys. Lett. A 266 （2000） 249] to the non-spherical case.