### Extremal Black Hole/CFT Correspondence in (Gauged

2 General Extremal Rotating Black Holes and CFT Duals It was argued in 13 from the general structure of four-dimensional extremal rotating black holes that the entropy of the black hole can be obtained from the Cardy formula of the two-dimensional conformal ﬁeld theory in the boundary of the black hole near-horizon geometry.

Get Price### general relativityHorizon of extremal black hole

· 3. In David Tong Lectures on General Relativity in section 6.2.5 there s discussion of extremal black holes. Metric takes the form d s 2 = − ( 1 − G M r) 2 d t 2 ( 1 − G M r) − 2 d r 2 r 2 d Ω 2 2. After that Tong calculate spatial distance After that he concluded Horizon of an extremal black hole lies at infinite spatial distance.

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Not Charge Rotation Scares The Theorist### Extremal Black Hole/CFT Correspondence in (Gauged

2 General Extremal Rotating Black Holes and CFT Duals It was argued in 13 from the general structure of four-dimensional extremal rotating black holes that the entropy of the black hole can be obtained from the Cardy formula of the two-dimensional conformal ﬁeld theory in the boundary of the black hole near-horizon geometry.

Get Price### Destroying Extremal Kerr–Newman-AdS Black Holes with

· Equation means that the event horizon of the black hole is destroyed and it implies that the test particle has a maximum value to destroy the KNA black hole.Equation ensures that Eq.() can be used as a physical criterionTo investigate the range of energy to destroy the black hole we choose the parameters and .Then the radius of the extremal black hole is 3.6384 and charge Q is 23.21758.

Get Price### general relativityHorizon of extremal black hole

· 3. In David Tong Lectures on General Relativity in section 6.2.5 there s discussion of extremal black holes. Metric takes the form d s 2 = − ( 1 − G M r) 2 d t 2 ( 1 − G M r) − 2 d r 2 r 2 d Ω 2 2. After that Tong calculate spatial distance After that he concluded Horizon of an extremal black hole lies at infinite spatial distance.

Get Price### Stability and Instability of Extremal Black Holes

· Existence of trapped null geodesics for general black hole backgrounds.On extremal R-N all trapped null geodesics approachr= 2Mwhichis the so-called photon sphere. The signicance of this hypersurface is that anyL2spacetime estimateover Bmust degenerate exactly on the photon sphere.Construction of a purely physical space multiplier.

Get Price### Extremal Black Hole/CFT Correspondence in (Gauged

2 General Extremal Rotating Black Holes and CFT Duals It was argued in 13 from the general structure of four-dimensional extremal rotating black holes that the entropy of the black hole can be obtained from the Cardy formula of the two-dimensional conformal ﬁeld theory in the boundary of the black hole near-horizon geometry.

Get Price### Primordial extremal black holes as dark matter

· We show that primordial (nearly) extremal black holes with a wide range of masses from the Planck scale to around 10 9 text text mat g could be cosmologically stable and provide a viable explanation for dark matter given a dark electromagnetism and a heavy dark electron. Hawking radiation and Schwinger discharge processes are suppressed by near extremality and the heaviness

Get Price### The extremal black hole bomb Semantic Scholar

The extremal black hole bomb. We analyze the spectrum of massive scalar bound states in the background of extremal Kerr black holes focusing on modes in the superradiant regime which grow exponentially in time and quickly deplete the black hole s mass and spin. Previous analytical estimates for the growth rate of this instability were

Get Price### thermodynamicsWhy Do Extremal Black Holes Not Radiate

· This is because in astrophysical black holes we expect the charge-to-mass ratio to be close to zero certainly absolutely negligibly as to the extremal charge-to-mass ratio. Mass which feeds black hole is almost always quasi-neutral and if an overcharge does come about it actually attracts more of the opposite sign and drives away the same

Get Price### Limits and special symmetries of extremal black holes

· a indication that a black hole can not be spun up to extremality. On top of this it turns out that black holes tend to have low electric charge. All hope is not lost since in string theory extremal black holes are of particular interest because in these extremal cases it has been possible to calculate black hole entropy from ﬁrst principles.

Get Price### Destroying Extremal Kerr–Newman-AdS Black Holes with

· Equation means that the event horizon of the black hole is destroyed and it implies that the test particle has a maximum value to destroy the KNA black hole.Equation ensures that Eq.() can be used as a physical criterionTo investigate the range of energy to destroy the black hole we choose the parameters and .Then the radius of the extremal black hole is 3.6384 and charge Q is 23.21758.

Get Price### Counting States of Near-Extremal Black HolesarXiv Vanity

The size of an extremal RR black hole (as measured by its Schwarzschild radius) is a power of its charge times the Planck length. Hence in string perturbation theory strings are treated as much larger than the RR black holes. The perturbative stringy description of a RR black hole is as a D-brane with no analog of an event horizon.

Get Price### Phys. Rev. D 88 101503(R) (2013)Extremal black holes

· Extremal black holes and the first law of thermodynamics Maria Johnstone M. M. Sheikh-Jabbari Joan Simón and Hossein Yavartanoo Phys. Rev. D 88 101503(R)

Get Price### Properties of extremal black holesUniversity of Adelaide

· Equivalently extremal black holes are defined as stationary black holes whose inner and outer horizons coincide. No physical process is known that would make an extremal black hole out of a non-extremal black hole. 5 If one attempts to send finely-tuned particles or waves into a near-extremal black hole in order to further approach extremality one realizes that there is a smaller and smaller

Get Price### Stability and Instability of Extremal Black Holes

· IntroductionStability Extremal R-NStability Extremal KerrInstabilityOngoing WorkConclusion The Intermediate Region Band Trapping E ect Existence of trapped null geodesics for general black hole backgrounds. On extremal R-N all trapped null geodesics approach r= 2Mwhich is the so-called photon sphere.

Get Price### Phys. Rev. D 88 101503(R) (2013)Extremal black holes

· Extremal black holes and the first law of thermodynamics Maria Johnstone M. M. Sheikh-Jabbari Joan Simón and Hossein Yavartanoo Phys. Rev. D 88 101503(R)

Get Price### Extremal Limits and Black Hole EntropyHarvard University

· The extremal black hole metric is given by ds2 = − (r−ρ)2 r2 dt2 r2 (r−ρ)2 dr2 r2dΩ2 2. (7) The causal structure of the (extremal and non-extremal) Reissner-Nordstro¨m black hole is shown in Fig. 1 (along with that of anti-de Sitter space). There are three diﬀerent types of patches labeled as follows Region I r

Get Price ### Extremal Limits and Black Hole EntropyHarvard University

· The extremal black hole metric is given by ds2 = − (r−ρ)2 r2 dt2 r2 (r−ρ)2 dr2 r2dΩ2 2. (7) The causal structure of the (extremal and non-extremal) Reissner-Nordstro¨m black hole is shown in Fig. 1 (along with that of anti-de Sitter space). There are three diﬀerent types of patches labeled as follows Region I r

Get Price ### Dynamics of Extremal Black Holes Stefanos Aretakis

The present Brief focuses on the dynamics of extremal black holes. Astronomical observations suggest that nearly 70 of all stellar black holes are near extremal. Hence a study of their dynamics is of great importance in advancing our knowledge of the structure of the universe.

Get Price### Extremal black holes and near-horizon geometry

· NHG of extremal black hole solution to some theory of gravity must also be a solution. Classify NHG solutions Einstein eqs for NHG equivalent to Einstein-like eqs on H. Problem of compact Riemannian geometry in D 2 dims. Gives potential horizon topologies and geometries of full extremal black hole solns. Can rule out black hole topologies.

Get Price### Entropy of an extremal electrically charged thin shell and

· An extremal black hole has zero temperature and if the temperature of the surrounding fields is nonzero then the stress-energy diverges strongly . This paper is committed to the study of the entropy of extremally charged spherically symmetric thin shells of any radii and in particular to the understanding of the entropy of the system when the

Get Price### Black Hole Paradoxes Reveal a Fundamental Link Between

· Black hole evaporation has informed quantum gravity research ever since. More recently physicists have considered the extreme of the extreme — entities called extremal black holes — and found a fruitful new problem. Black holes become electrically charged when charged stuff falls into them.

Get Price### The extremal black hole bomb Semantic Scholar

The extremal black hole bomb. We analyze the spectrum of massive scalar bound states in the background of extremal Kerr black holes focusing on modes in the superradiant regime which grow exponentially in time and quickly deplete the black hole s mass and spin. Previous analytical estimates for the growth rate of this instability were

Get Price### Primordial extremal black holes as dark matter

· We show that primordial (nearly) extremal black holes with a wide range of masses from the Planck scale to around 10 9 text text mat g could be cosmologically stable and provide a viable explanation for dark matter given a dark electromagnetism and a heavy dark electron. Hawking radiation and Schwinger discharge processes are suppressed by near extremality and the heaviness

Get Price### Overcharging and Overspinning a Black Hole

· The black hole is a near-extremal Reissner-Nordstrom black hole with no angular momentum different than Wald s extremal Kerr black hole with charge and angular momentum. Her conditions for destroying the horizon are that 1) the particle falls past the event horizon 2) the final

Get Price### Phys. Rev. D 77 064005 (2008)Near extremal black hole

· Near extremal black hole entropy as entanglement entropy via AdS 2 / CFT 1 Tatsuo Azeyanagi Tatsuma Nishioka and Tadashi Takayanagi Phys. Rev.

Get Price### Extremal black holes and near-horizon geometry

· NHG of extremal black hole solution to some theory of gravity must also be a solution. Classify NHG solutions Einstein eqs for NHG equivalent to Einstein-like eqs on H. Problem of compact Riemannian geometry in D 2 dims. Gives potential horizon topologies and geometries of full extremal black hole solns. Can rule out black hole topologies.

Get Price### Extremal Black Hole/CFT Correspondence in (Gauged