Quantum Evaporation of a Naked Singularity

The thermodynamic theory underlying black hole processes is developed in detail and applied to model systems. I t is found that Kerr-Newman black holes undergo a phase transition at a = 0.68 M or Q = 0.86 M , where the heat capacity has an infinite discontinuity. Above the transition values the specific heat is positive, permitting isothermal equilibrium with a surrounding heat bath. Simple processes and stability criteria for various black hole situations are investigated. The limits for entropieally favoured black hole formation are found. The Nernst conditions for the third law of thermodynamics are not satisfied fully for black holes. There is no obvious thermodynamic reason why a black hole may not be cooled down below absolute zero and converted into a naked singularity. Quantum energy-momentum tensor calculations for uncharged black holes are extended to the Reissner-Nordstrom case, and found to be fully consistent with the thermodynamic picture for Q < M . For Q > M the model predicts that ‘naked’ collapse also produces radiation, with such intensity that the collapsing matter is entirely evaporated away before a naked singularity can form.

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Shadow of a naked singularity

Physical Review D ◽

10.1103/physrevd.92.044035 ◽

2015 ◽

Vol 92 (4) ◽

Cited By ~ 12

Author(s):

Néstor Ortiz ◽

Olivier Sarbach ◽

Thomas Zannias

Keyword(s):

Naked Singularity

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NUMERICAL STUDY OF THE INTERACTION BETWEEN POSITIVE AND NEGATIVE MASS OBJECTS IN GENERAL RELATIVITY

International Journal of Modern Physics D ◽

10.1142/s0218271812500617 ◽

2012 ◽

Vol 21 (07) ◽

pp. 1250061 ◽

Cited By ~ 2

Author(s):

ZHOUJIAN CAO

Keyword(s):

Boundary Condition ◽

General Relativity ◽

Numerical Study ◽

Naked Singularity ◽

Newtonian Limit ◽

Computational Domain ◽

Positive Mass ◽

Negative Mass ◽

Mass Particle ◽

Causal Property

Based on Baumgarte–Shapiro–Shibata–Nakamura formalism and moving puncture method, we demonstrate the first numerical evolutions of the interaction between positive and negative mass objects. Using the causal property of general relativity, we set our computational domain around the positive mass black hole while excluding the region around the naked singularity introduced by the negative mass object. Besides the usual Sommerfeld numerical boundary condition, an approximate boundary condition is proposed for this nonasymptotically-flat computational domain. Careful checks show that either boundary condition introduces smaller error than the numerical truncation errors. This is consistent with the causal property of general relativity. Except for the numerical truncation error and round-off error, our method gives an exact solution to the full Einstein's equation for a portion of spacetime with two objects whose masses have opposite signs. So our method opens the door for numerical explorations with negative mass objects. Based on this method, we investigate the Newtonian limit of spacetime with two objects whose masses have opposite sign. Our result implies that this spacetime does have a Newtonian limit which corresponds to a negative mass particle chasing a positive mass particle. This result sheds some light on an interesting debate about the Newtonian limit of a spacetime with positive and negative point masses.

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Classical instability of a naked singularity

Nature ◽

10.1038/273429a0 ◽

1978 ◽

Vol 273 (5662) ◽

pp. 429-431 ◽

Cited By ~ 28

Author(s):

F. de Felice

Keyword(s):

Naked Singularity

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Behavior of a vacuum and naked singularity under a smooth gauge function in Lyra geometry

Canadian Journal of Physics ◽

10.1139/cjp-2017-0681 ◽

2018 ◽

Vol 96 (9) ◽

pp. 969-977

Author(s):

Haizhao Zhi

Keyword(s):

Physical Meaning ◽

Conformal Geometry ◽

Naked Singularity ◽

Lyra Geometry ◽

Space Time ◽

Gauge Function ◽

Weyl Geometry ◽

Irregular Singular Point ◽

New Space ◽

Symmetric Gauge

Lyra geometry is a conformal geometry that originated from Weyl geometry. In this article, we derive the exterior field equation under a spherically symmetric gauge function x0(r) and metric in Lyra geometry. When we impose a specific form of the gauge function x0(r), the radial differential equation of the metric component g00 will possess an irregular singular point (ISP) at r = 0. Moreover, we can apply the method of dominant balance to get the asymptotic behavior of the new space–time solution. The significance of this work is that we can use a series of smooth gauge functions x0(r) to modulate the degree of divergence of the singularity at r = 0, which will become a naked singularity under certain conditions. Furthermore, we investigate the physical meaning of this novel behavior of space–time in Lyra geometry and find out that no spaceship with finite integrated acceleration can arrive at this singularity at r = 0. The physical meaning of the gauge function and integrability is also discussed.

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Gravitational collapse of type N spacetime, the naked singularity, and causality violation

Progress of Theoretical and Experimental Physics ◽

10.1093/ptep/ptx134 ◽

2017 ◽

Vol 2017 (9) ◽

Cited By ~ 9

Author(s):

Faizuddin Ahmed

Keyword(s):

Gravitational Collapse ◽

Naked Singularity ◽

Causality Violation

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Axial symmetry causality violating spacetime and the naked singularity

International Journal of Geometric Methods in Modern Physics ◽

10.1142/s0219887818501530 ◽

2018 ◽

Vol 15 (09) ◽

pp. 1850153 ◽

Cited By ~ 3

Author(s):

Faizuddin Ahmed

Keyword(s):

Symmetry Axis ◽

Energy Content ◽

Naked Singularity ◽

Energy Conditions ◽

Field Equations ◽

Closed Timelike Curves ◽

Radiation Fields ◽

Strong Curvature ◽

Anisotropic Fluids ◽

Matter Energy

A non-spherical solution of Einstein’s field equations, possessing a naked curvature singularity on the symmetry axis, satisfying the strong curvature condition, is presented. The spacetime admits closed timelike curves which appear after a certain instant of time in a causally well-behaved manner. The matter–energy content radiation fields, coupled with anisotropic fluids, obeying the energy conditions, diverge on the symmetry axis.

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