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36
Rotating black holes in gauged supergravities: Thermodynamics, supersymmetric limits, topological solitons and time machines
, 2005
"... We study the thermodynamics of the recentlydiscovered nonextremal charged rotating black holes of gauged supergravities in five, seven and four dimensions, obtaining energies, angular momenta and charges that are consistent with the first law of thermodynamics. We obtain their supersymmetric limit ..."
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Cited by 39 (12 self)
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We study the thermodynamics of the recentlydiscovered nonextremal charged rotating black holes of gauged supergravities in five, seven and four dimensions, obtaining energies, angular momenta and charges that are consistent with the first law of thermodynamics. We obtain their supersymmetric limits by using these expressions together with an analysis of the AdS superalgebras including Rcharges. We give a general discussion of the global structure of such solutions, and apply it in the various cases. We obtain new regular supersymmetric black holes in seven and four dimensions, as well as reproducing known examples in five and four dimensions. We also obtain new supersymmetric nonsingular topological solitons in five and seven dimensions. The rest of the supersymmetric solutions either have naked singularities or naked time machines. The latter can be rendered nonsingular if the asymptotic time is periodic. This leads to a new type of quantum consistency condition, which we call a Josephson quantisation condition. Finally, we discuss some aspects of rotating black holes in Gödel universe backgrounds.
Supersymmetric Gödel Universes in String Theory
, 2003
"... Supersymmetric backgrounds in string and Mtheory of the Gödel Universe type are studied. We find several new Gödel Universes that preserve up to 20 supersymmetries. In particular, we obtain an interesting Gödel Universe in Mtheory with 18 supersymmetries which does not seem to be dual to a ppwave ..."
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Cited by 29 (0 self)
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Supersymmetric backgrounds in string and Mtheory of the Gödel Universe type are studied. We find several new Gödel Universes that preserve up to 20 supersymmetries. In particular, we obtain an interesting Gödel Universe in Mtheory with 18 supersymmetries which does not seem to be dual to a ppwave. We show that not only Tduality but also the typeIIA/Mtheory Sduality can give supersymmetric Gödel Universes from ppwaves. We find solutions that can interpolate between Gödel Universes and ppwaves. We also compute the string spectrum on two type IIA Gödel Universes. Furthermore, we obtain the spectrum of Dbranes on a Gödel Universe and find the supergravity solution for a D4brane on a
An exact string theory model of Closed Time–Like Curves and Cosmological Singularities
, 2004
"... We study an exact model of string theory propagating in a space–time containing regions with closed time–like curves (CTCs) separated from a finite cosmological region bounded by a Big Bang and a Big Crunch. The model is an non–trivial embedding of the Taub–NUT geometry into heterotic string theory ..."
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Cited by 25 (3 self)
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We study an exact model of string theory propagating in a space–time containing regions with closed time–like curves (CTCs) separated from a finite cosmological region bounded by a Big Bang and a Big Crunch. The model is an non–trivial embedding of the Taub–NUT geometry into heterotic string theory with a full conformal field theory (CFT) definition, discovered over a decade ago as a heterotic coset model. Having a CFT definition makes this an excellent laboratory for the study of the stringy fate of CTCs, the Taub cosmology, and the Milne/Misner–type chronology horizon which separates them. In an effort to uncover the role of stringy corrections to such geometries, we calculate the complete set of α ′ corrections to the geometry. We observe that the key features of Taub–NUT persist in the exact theory, together with the emergence of a region of space with Euclidean signature bounded by time–like curvature singularities. Although such remarks are premature, their persistence in the exact geometry is suggestive that string theory theory is able to make physical sense of the Milne/Misner singularities and the CTCs, despite their pathological character in General Relativity. This may also support the possibility that CTCs may be viable in some physical situations, and may be a natural ingredient in pre–Big–Bang cosmological scenarios.
Black holes in Gödel universes and ppwaves
"... We find exact rotating and nonrotating neutral black hole solutions in the Gödel universe of the five dimensional minimal supergravity theory. We also describe the embedding of this solution in Mtheory. After dimensional reduction and Tduality, we obtain a supergravity solution corresponding to p ..."
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We find exact rotating and nonrotating neutral black hole solutions in the Gödel universe of the five dimensional minimal supergravity theory. We also describe the embedding of this solution in Mtheory. After dimensional reduction and Tduality, we obtain a supergravity solution corresponding to placing a black string in a ppwave background. The Gödel universe [1] is an exact solution of Einstein’s equations in the presence of a cosmological constant and homogeneous pressureless matter. This spacetime solution exhibits several peculiar features including in particular the presence of closed timelike curve through every point. Recently, a spacetime exhibiting most of the peculiar features of Gödel universes was shown to be an exact solution of minimal supergravity in 4+1 dimensions, preserving some number of supersymmetries [2, 3]. As a result, these solutions can be embedded in supergravity theories of 10 or 11 dimensions and may constitute consistent backgrounds of string theory. The consistency of this solution was further investigated recently by [4, 5] who found that the supersymmetric Gödel universes of [2, 3] are related by Tduality to the ppwave solutions, which have generated significant interest recently
Boundary states for supertubes in flat spacetime and Gödel universe
 JHEP
, 2003
"... We construct boundary states for supertubes in the flat spacetime. The Tdual objects of supertubes are moving spiral D1branes (Dhelices). Since we can obtain these Dhelices from the usual D1branes via null deformation, we can construct the boundary states for these moving Dhelices in the covar ..."
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We construct boundary states for supertubes in the flat spacetime. The Tdual objects of supertubes are moving spiral D1branes (Dhelices). Since we can obtain these Dhelices from the usual D1branes via null deformation, we can construct the boundary states for these moving Dhelices in the covariant formalism. Using these boundary states, we calculate the vacuum amplitude between two supertubes in the closed string channel and read the open string spectrum via the open closed duality. We find there are critical values of the energy for onshell open strings on the supertubes due to the nontrivial stringy correction. We also consider supertubes in the type IIA Gödel universe in order to use them as probes of closed timelike curves. This universe is the Tdual of the maximally supersymmetric type IIB PPwave background. Since the null deformations of Dbranes are also allowed in this PPwave, we can construct the boundary states for supertubes in the type IIA Gödel universe in the same way. We obtain the open string spectrum on the supertube from the vacuum amplitude between supertubes. As a consequence, we find that the tachyonic instability of open strings on the supertube, which is the signal of closed time like curves, disappears due to the stringy correction. 1
The Taming of Closed Time–like Curves
"... We formulate QFT on a R 1,d /Z2 orbifold, in a manner which is invariant under the Z2 time and space reversal. This is a background with closed timelike curves. It is also relevant for the elliptic interpretation of de Sitter space. We calculate the oneloop vacuum expectation value of the stress t ..."
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Cited by 12 (1 self)
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We formulate QFT on a R 1,d /Z2 orbifold, in a manner which is invariant under the Z2 time and space reversal. This is a background with closed timelike curves. It is also relevant for the elliptic interpretation of de Sitter space. We calculate the oneloop vacuum expectation value of the stress tensor in the invariant QFT, and show that it does not diverge at the boundary of the region of closed timelike curves. Rather, the only divergence is at the initial time slice of the orbifold, analogous to a spacelike BigBang singularity. We then calculate the oneloop graviton tadpole in bosonic string theory, and show that the answer is the same as if the target space would be just the Minkowski space R 1,d, suggesting that the tadpole vanishes for the superstring. Finally, we argue that it is possible to define local Smatrices, even if the spacetime is globally timenonorientable.
On a class of 4D Kahler bases and AdS(5) supersymmetric Black Holes” [arXiv:hepth/0608201
"... We construct a class of toric Kähler manifolds, M4, of real dimension four, a subset of which corresponds to the Kähler bases of all known 5D asymptotically AdS5 supersymmetric blackholes. In a certain limit, these Kähler spaces take the form of cones over Sasaki spaces, which, in turn, are fibrati ..."
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Cited by 5 (0 self)
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We construct a class of toric Kähler manifolds, M4, of real dimension four, a subset of which corresponds to the Kähler bases of all known 5D asymptotically AdS5 supersymmetric blackholes. In a certain limit, these Kähler spaces take the form of cones over Sasaki spaces, which, in turn, are fibrations over toric manifolds of real dimension two. The metric on M4 is completely determined by a single function H(x), which is the conformal factor of the two dimensional space. We study the solutions of minimal five dimensional gauged supergravity having this class of Kähler spaces as base and show that in order to generate a five dimensional solution H(x) must obey a simple sixth order differential equation. We discuss the solutions in detail, which include all known asymptotically AdS5 black holes as well as other spacetimes with noncompact horizons. Moreover we find an infinite number of supersymmetric deformations of these spacetimes with less spatial isometries than the base space. These deformations vanish at the horizon, but become relevant asymptotically.
Rotating Black Holes in a Gödel Universe
, 2003
"... We construct a five–dimensional, asymptotically Gödel, three–charge black hole via dimensional reduction of an asymptotically plane wave, rotating D1D5brane solution of type IIB supergravity. This latter is itself constructed via the solution generating procedure of Garfinkle and Vachaspati, appli ..."
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Cited by 5 (0 self)
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We construct a five–dimensional, asymptotically Gödel, three–charge black hole via dimensional reduction of an asymptotically plane wave, rotating D1D5brane solution of type IIB supergravity. This latter is itself constructed via the solution generating procedure of Garfinkle and Vachaspati, applied to the standard rotating D1D5brane solution. Taking all charges to be equal gives a “BMPV Gödel black hole”, which is closely related to that recently found by Herdeiro. We emphasise, however, the importance of our ten–dimensional microscopic description in terms of branes. We discuss various properties of the asymptotically Gödel black hole, including the physical bound on the rotation of the hole, the existence of closed timelike curves, and possible holographic protection of chronology. 1 1
Tunnelling From Gödel Black Holes
, 2008
"... We consider the spacetime structure of KerrGödel black holes, analyzing their parameter space KerrGödel in detail. We apply the tunnelling method to compute their temperature and compare the results to previous calculations obtained via other methods. We claim that it is not possible to have the C ..."
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We consider the spacetime structure of KerrGödel black holes, analyzing their parameter space KerrGödel in detail. We apply the tunnelling method to compute their temperature and compare the results to previous calculations obtained via other methods. We claim that it is not possible to have the CTC horizon in between the two black hole horizons and include a discussion of issues that occur when the radius of the CTC horizon is smaller than the radius of both black hole horizons. 1