Nut Charged Space-times and Closed Timelike Curves on the Boundary

Astefanesei, Dumitru; Mann, Robert B.; Radu, Eugen

doi:10.1088/1126-6708/2005/01/049

Cited by 85 publications

(123 citation statements)

References 89 publications

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“…Comparing this to the result ( [23]) for the hyperbolic Taub-NUT temperature obtained from Wick rotation methods…”

Section: Taub-nut-adsmentioning

confidence: 58%

“…which is the same form found using the Wick rotation method [24,23]. To demonstrate this is straightforward.…”

Section: Taub-nut-adsmentioning

confidence: 61%

“…Here there is no well defined total mass or energy as with Schwarzschild, but there are well defined horizons. The metric (23) locates the horizon at x = 1 a , whereas for the metric (24) it is at x = 0 . We consider a null particle to be emitted from the Rindler horizon, and it is reasonable to assume the emitted particle will have a Hamiltonian associated with it.…”

Section: Rindler Spacementioning

confidence: 99%

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Tunnelling, temperature, and Taub-NUT black holes

2006

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We investigate quantum tunnelling methods for calculating black hole temperature, specifically the null geodesic method of Parikh and Wilczek and the Hamilton-Jacobi Ansatz method of Angheben et al. We consider application of these methods to a broad class of spacetimes with event horizons, inlcuding Rindler and non-static spacetimes such as KerrNewman and Taub-NUT. We obtain a general form for the temperature of Taub-NUT-Ads black holes that is commensurate with other methods. We examine the limitations of these methods for extremal black holes, taking the extremal Reissner-Nordstrom spacetime as a case in point.

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“…Comparing this to the result ( [23]) for the hyperbolic Taub-NUT temperature obtained from Wick rotation methods…”

Section: Taub-nut-adsmentioning

confidence: 58%

“…which is the same form found using the Wick rotation method [24,23]. To demonstrate this is straightforward.…”

Section: Taub-nut-adsmentioning

confidence: 61%

Section: Rindler Spacementioning

confidence: 99%

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Tunnelling, temperature, and Taub-NUT black holes

2006

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“…This is manifest in higher derivative gravity [14]. A NUT charge, which changes the asymptotic structure of spacetime, also leads to a modification of the area law [15], [23]. We may ask if the interaction between two black holes, within general relativity and in an asymptotically flat configuration, may also violate this law.…”

Section: Further Remarksmentioning

confidence: 99%

Bekenstein-Hawking area law for black objects with conical singularities

et al. 2010

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We argue that, when working with the appropriate set of thermodynamical variables, the BekensteinHawking law still holds for asymptotically flat black objects with conical singularities. The mass-energy which enters the first law of thermodynamics does not, however, coincide with the ADM mass; it differs from the latter by the energy associated with the conical singularity, as seen by an asymptotic, static observer. These statements are supported by a number of examples: the Bach-Weyl (double-Schwarzschild) solution, its dihole generalisation in Einstein-Maxwell theory and the five dimensional static black ring. IntroductionConical singularities have a topological nature. They arise from identifications along the orbits of a U (1) isometry, in the neighbourhood of a fixed point of this symmetry. It is therefore somewhat surprising that there are circumstances under which the local equations of general relativity demand the existence of conical singularities. One such circumstance is realised in non-extremal multi-black hole solutions. The long range interactions in these solutions are unable to provide equilibrium between the various black holes. The role of the conical singularities is to provide the force balance that allows the existence of such solutions in a non-linear theory. The basic example is the Bach-Weyl (BW) or double-Schwarzschild solution [1], which describes two static black holes in four dimensional vacuum general relativity. This configuration belongs to the general class of static Ricci flat vacua with a U (1) isometry found by Weyl [2], and it was generalised to N collinear Schwarzschild black holes by Israel and Khan [3]. The occurrence of conical singularities in the BW solutions was first discussed by Einstein and Rosen [4]; the generic solution must have these singularities, albeit their precise location is a matter of choice. Depending on the choice of periodicity for the coordinate along the U (1) orbits, the conical singularity can be put either in between the two black holes -in which case it is interpreted as a strut -or connecting either black hole to infinity -in which case it is interpreted as a string. In order for the spacetime to be asymptotically flat (without any conical singularities at spatial infinity), we shall take the former viewpoint. The strut energy is then interpreted as the interaction energy between the black holes, while its pressure prevents the gravitational collapse of the system.Another such circumstance is realised in unbalanced single black hole solutions. In more than four spacetime dimensions, there are black objects with a topologically non-spherical horizon that, in vacuum, can only be balanced in a regular (on and outside the event horizon) geometry by introducing rotation. Their static version possesses conical singularities. The basic example is the static black ring [5,6] in five spacetime dimensions. As before, the precise location of the conical singularity is a matter of choice. Demanding regularity at spatial infinity one finds a (spatia...

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“…An open question is whether or not naked singularities and backgrounds with CTCs can be solved by quantum effects in a theory of quantum gravity. Related to this point we would like to emphasize that examples of how naked singularities and CTCs can be solved appear in string theory (see for instance [5][6][7][8][9][10]). As we will demonstrate in the case of naked singularities, the radial velocity of a massless particle exceeds the value 1 in the Schwarzschild coordinates in certain space regions, i.e.…”

Section: Introductionmentioning

confidence: 99%

Velocity and velocity bounds in static spherically symmetric metrics

2011

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Abstract:We find simple expressions for velocity of massless particles with dependence on the distance, , in Schwarzschild coordinates. For massive particles these expressions give an upper bound for the velocity. Our results apply to static spherically symmetric metrics. We use these results to calculate the velocity for different cases: Schwarzschild, Schwarzschild-de Sitter and Reissner-Nordström with and without the cosmological constant. We emphasize the differences between the behavior of the velocity in the different metrics and find that in cases with naked singularity there always exists a region where the massless particle moves with a velocity greater than the velocity of light in vacuum. In the case of Reissner-Nordström-de Sitter we completely characterize the velocity and the metric in an algebraic way. We contrast the case of classical naked singularities with naked singularities emerging from metric inspired by noncommutative geometry where the radial velocity never exceeds one. Furthermore, we solve the Einstein equations for a constant and polytropic density profile and calculate the radial velocity of a photon moving in spaces with interior metric. The polytropic case of radial velocity displays an unexpected variation bounded by a local minimum and maximum.

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Nut Charged Space-times and Closed Timelike Curves on the Boundary

Cited by 85 publications

References 89 publications

Tunnelling, temperature, and Taub-NUT black holes

Tunnelling, temperature, and Taub-NUT black holes

Bekenstein-Hawking area law for black objects with conical singularities

Velocity and velocity bounds in static spherically symmetric metrics

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