scholarly journals New gedanken experiment on higher-dimensional asymptotically AdS Reissner–Nordström black hole

2020 ◽  
Vol 80 (9) ◽  
Author(s):  
Ming Zhang ◽  
Jie Jiang
Keyword(s):  
Black Hole ◽  
Cosmological Constant ◽  
Order Approximation ◽  
Energy Condition ◽  
Null Energy Condition ◽  
Matter Field ◽  
Second Order ◽  
Field Perturbation ◽  
Higher Dimensional ◽  
Dynamical Quantity

AbstractViewing the negative cosmological constant as a dynamical quantity derived from the matter field, we study the weak cosmic censorship conjecture for the higher-dimensional asymptotically AdS Reissner–Nordström black hole. To this end, using the stability assumption of the matter field perturbation and the null energy condition of the matter field, we first derive the first-order and second-order perturbation inequalities containing the variable cosmological constant and its conjugate quantity for the black hole. We prove that the higher-dimensional RN-AdS black hole cannot be destroyed under a second-order approximation of the matter field perturbation process.

scholarly journals New version of the gedanken experiments to test the weak cosmic censorship in charged dilaton-Lifshitz black holes

2020 ◽  
Vol 80 (9) ◽  
Author(s):  
Jie Jiang ◽  
Ming Zhang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Order Approximation ◽  
Energy Condition ◽  
Null Energy Condition ◽  
Cosmic Censorship ◽  
Second Order ◽  
Lifshitz Black Holes ◽  
Lifshitz Black Hole ◽  
Matter Fields

AbstractIn this paper, based on the new version of the gedanken experiments proposed by Sorce and Wald, we examine the weak cosmic censorship in the perturbation process of accreting matter fields for the charged dilaton-Lifshitz black holes. In the investigation, we assume that the black hole is perturbed by some extra matter source satisfied the null energy condition and ultimately settle down to a static charged dilaton-Lifshitz black hole in the asymptotic future. Then, after applying the Noether charge method, we derive the first-order and second-order perturbation inequalities of the perturbation matter fields. As a result, we find that the nearly extremal charged dilaton-Lifshitz black hole cannot be destroyed under the second-order approximation of perturbation. This result implies that the weak cosmic censorship conjecture might be a general feature of the Einstein gravity, and it is independent of the asymptotic behaviors of the black holes.

Kerr–Newman black holes cannot be over-charged or over-spun

2018 ◽  
Vol 27 (11) ◽  
pp. 1843003 ◽  
Author(s):  
Robert M. Wald
Keyword(s):  
Black Hole ◽  
Energy Condition ◽  
Finite Size ◽  
Null Energy Condition ◽  
Second Order ◽  
Energy Tensor ◽  
Finite Size Effects ◽  
Stress Energy ◽  
Newman Black Hole ◽  
Self Force

I describe research done in collaboration with J. Sorce showing that one cannot over-charge and/or over-spin an initially slightly nonextremal Kerr–Newman black hole via the type of gedanken experiments proposed by Hubeny and others, assuming that the nonelectromagnetic stress-energy tensor of the matter entering the black hole satisfies the null energy condition. Analysis of such gedanken experiments requires that we calculate all effects on the final mass of the black hole that are second-order in the charge and the angular momentum carried into the black hole. We do so using Lagrangian methods, and our formula for the second-order correction to mass, [Formula: see text], is obtained by generalizing the canonical energy analysis of Hollands and Wald to the Einstein–Maxwell case. Our formula for [Formula: see text] automatically includes all self-force and finite size effects.

scholarly journals Gedanken experiments at high-order approximation: Kerr black hole cannot be overspun

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Aofei Sang ◽  
Jie Jiang
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Order Approximation ◽  
Energy Condition ◽  
Kerr Black Hole ◽  
Null Energy Condition ◽  
Higher Order ◽  
High Order ◽  
Order Perturbation ◽  
Kerr Black Holes

Abstract Sorce and Wald proposed a new version of gedanken experiments to examine the weak cosmic censorship conjecture (WCCC) in Kerr-Newmann black holes. However, their discussion only includes the second-order approximation of perturbation and there exists an optimal condition such that the validity of the WCCC is determined by the higher-order approximations. Therefore, in this paper, we extended their discussions into the high-order approximations to study the WCCC in a nearly extremal Kerr black hole. After assuming that the spacetime satisfies the stability condition and the perturbation matter fields satisfy the null energy condition, based on the Noether charge method by Iyer and Wald, we completely calculate the first four order perturbation inequalities and discuss the corresponding gedanken experiment to overspin the Kerr black hole. As a result, we find that the nearly extremal Kerr black holes cannot be destroyed under the fourth-order approximation of perturbation. Then, by using the mathematical induction, we strictly prove the nth order perturbation inequality when the first (n − 1) order perturbation inequalities are saturated. Using these results, we discuss the first 100 order approximation of the gedanken experiments and find that the WCCC in Kerr black hole is valid under the higher-order approximation of perturbation. Our investigation implies that the WCCC might be strictly satisfied in Kerr black holes under the perturbation level.

scholarly journals Singularity Theorems in the Effective Field Theory for Quantum Gravity at Second Order in Curvature

Universe ◽  
2020 ◽  
Vol 6 (10) ◽  
pp. 171
Author(s):  
Folkert Kuipers ◽  
Xavier Calmet
Keyword(s):  
Field Theory ◽  
Quantum Gravity ◽  
Effective Field Theory ◽  
Energy Condition ◽  
Null Energy Condition ◽  
Effective Field ◽  
Second Order ◽  
Jordan Frame ◽  
Singularity Theorems ◽  
Massive Spin

In this paper, we discuss singularity theorems in quantum gravity using effective field theory methods. To second order in curvature, the effective field theory contains two new degrees of freedom which have important implications for the derivation of these theorems: a massive spin-2 field and a massive spin-0 field. Using an explicit mapping of this theory from the Jordan frame to the Einstein frame, we show that the massive spin-2 field violates the null energy condition, while the massive spin-0 field satisfies the null energy condition, but may violate the strong energy condition. Due to this violation, classical singularity theorems are no longer applicable, indicating that singularities can be avoided, if the leading quantum corrections are taken into account.

scholarly journals Higher-dimensional evolving wormholes satisfying the null energy condition

2014 ◽  
Vol 90 (2) ◽  
Author(s):  
Mahdi Kord Zangeneh ◽  
Francisco S. N. Lobo ◽  
Nematollah Riazi
Keyword(s):  
Energy Condition ◽  
Null Energy Condition ◽  
Higher Dimensional

TIME MACHINE AT THE LHC

2008 ◽  
Vol 05 (04) ◽  
pp. 641-651 ◽  
Author(s):  
I. YA. AREF'EVA ◽  
I. V. VOLOVICH
Keyword(s):  
Black Hole ◽  
Cross Section ◽  
Production Cross ◽  
Hadron Collider ◽  
Energy Condition ◽  
Null Energy Condition ◽  
Time Machine ◽  
Proton Proton ◽  
Traversable Wormhole ◽  
Time Machines

Recently, black hole and brane production at CERN's Large Hadron Collider (LHC) has been widely discussed. We suggest that there is a possibility to test causality at the LHC. We argue that if the scale of quantum gravity is of the order of few TeVs, proton-proton collisions at the LHC could lead to the formation of time machines (spacetime regions with closed timelike curves) which violate causality. One model for the time machine is a traversable wormhole. We argue that the traversable wormhole production cross section at the LHC is of the same order as the cross section for the black hole production. Traversable wormholes assume violation of the null energy condition (NEC) and an exotic matter similar to the dark energy is required. Decay of the wormholes/time machines and signatures of time machine events at the LHC are discussed.

scholarly journals Extracting Hawking radiation near the horizon of AdS black holes

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Krishan Saraswat ◽  
Niayesh Afshordi
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Evaporation Rate ◽  
Order Term ◽  
Energy Condition ◽  
Null Energy Condition ◽  
Leading Order ◽  
Proper Distance ◽  
Ads Black Holes ◽  
A Cell

Abstract We study how the evaporation rate of spherically symmetric black holes is affected through the extraction of radiation close to the horizon. We adopt a model of extraction that involves a perfectly absorptive screen placed close to the horizon and show that the evaporation rate can be changed depending on how close to the horizon the screen is placed. We apply our results to show that the scrambling time defined by the Hayden-Preskill decoding criterion, which is derived in Pennington’s work (arXiv:1905.08255) through entanglement wedge reconstruction is modified. The modifications appear as logarithmic corrections to Pennington’s time scale which depend on where the absorptive screen is placed. By fixing the proper distance between the horizon and screen we show that for small AdS black holes the leading order term in the scrambling time is consistent with Pennington’s scrambling time. However, for large AdS black holes the leading order Log contains the Bekenstein-Hawking entropy of a cell of characteristic length equal to the AdS radius rather than the entropy of the full horizon. Furthermore, using the correspondence between the radial null energy condition (NEC) and the holographic c-theorem, we argue that the screen cannot be arbitrarily close to the horizon. This leads to a holographic argument that black hole mining using a screen cannot significantly alter the lifetime of a black hole.

scholarly journals Wormhole geometries supported by quark matter at ultra-high densities

2014 ◽  
Vol 24 (01) ◽  
pp. 1550006 ◽  
Author(s):  
Tiberiu Harko ◽  
Francisco S. N. Lobo ◽  
M. K. Mak
Keyword(s):  
Quark Matter ◽  
Equations Of State ◽  
Order Approximation ◽  
Energy Condition ◽  
Theoretical Models ◽  
Null Energy Condition ◽  
Experimental Investigations ◽  
Gap Functions ◽  
Massachusetts Institute Of Technology ◽  
Institute Of Technology

A fundamental ingredient in wormhole physics is the presence of exotic matter, which involves the violation of the null energy condition (NEC). In this context, we investigate the possibility that wormholes could be supported by quark matter at extreme densities. Theoretical and experimental investigations of the structure of baryons show that strange quark matter, consisting of the u, d and s quarks, is the most energetically favorable state of baryonic matter. Moreover, at ultra-high densities, quark matter may exist in a variety of superconducting states, namely, the Color–Flavor-Locked (CFL) phase. Motivated by these theoretical models, we explore the conditions under which wormhole geometries may be supported by the equations of state (EOS) considered in the theoretical investigations of quark–gluon interactions. For the description of the normal quark matter, we adopt the Massachusetts Institute of Technology (MIT) bag model EOS, while the color superconducting quark phases are described by a first-order approximation of the free energy. By assuming specific forms for the bag and gap functions, several wormhole models are obtained for both normal and superconducting quark matter. The effects of the presence of an electrical charge are also taken into account.

scholarly journals Non-Rindler horizons and radiating black holes

2021 ◽  
pp. 2150184
Author(s):  
Vaibhav Wasnik
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Energy Condition ◽  
Null Energy Condition ◽  
Space Time ◽  
Coordinate Transformations ◽  
Spatial Infinity ◽  
Rindler Space ◽  
Black Hole Solutions

In this work we construct metrics corresponding to radiating black holes whose near horizon regions cannot be approximated by Rindler space–time. We first construct infinite parameter coordinate transformations from Minkowski coordinates, such that an observer using these coordinates to describe space–time events measures the Minkowski vacuum to be Planckian. Utilizing these results, we construct a family of black holes that radiate at spatial infinity. As an illustration, we study a subset of the black hole solutions and show that they satisfy the null energy condition.

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