Boundary states for supertubes in flat spacetime and Gödel universe

Takayanagi, Hiromitsu

doi:10.1088/1126-6708/2003/12/011

Cited by 25 publications

(15 citation statements)

References 45 publications

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“…For example Gödel type solutions have been shown to be T-dual to pp-waves [3]- [5]. Since closed-timelike curves (CTCs) exist in Gödel spacetimes these solutions can be used to investigate the implications of CTCs for string theory [6,7,9,11].…”

Section: Introductionmentioning

confidence: 99%

Tunnelling from Gödel black holes

2007

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We consider the spacetime structure of Kerr-Gödel black holes, analyzing their parameter space Kerr-Gödel 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.

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Section: Introductionmentioning

confidence: 99%

Tunnelling from Gödel black holes

2007

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“…However, since the Nappi-Witten model is constructed as a gauged WZW model, it seems natural to think that the model describes a consistent background. A famous example with non-trivial CTC is Gödel universe [50], and recently there are several studies, e.g., in [22,23,24,21,25,26,27,28] regarding the properties of CTCs in superstring backgrounds of Gödel type. In particular, ref.…”

Section: D-branes In the Whisker Regionsmentioning

confidence: 99%

“…1The organization of the paper is as follows. In section 2, we review the geometry of 1 See, e.g., [22,23,24,21,25,26,27,28] for recent discussions on CTCs in supersymmetric Gödel-type universes.…”

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D-branes in a big bang/big crunch universe: Nappi-Witten gauged WZW model

Hikida

Nayak

Panigrahi

2005

J. High Energy Phys.

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We study D-branes in the Nappi-Witten model, which is a gauged WZW model based on (SL(2, R)×SU (2))/(U (1)×U (1)). The model describes a four dimensional space-time consisting of cosmological regions with big bang/big crunch singularities and static regions with closed time-like curves. The aim of this paper is to investigate by D-brane probes whether there are pathologies associated with the cosmological singularities and the closed time-like curves. We first classify D-branes in a group theoretical way, and then examine DBI actions for effective theories on the D-branes.In particular, we show that D-brane metric from the DBI action does not include singularities, and wave functions on the D-branes are well behaved even in the presence of closed time-like curves. * The formulation of string theory in cosmological or broadly time-dependent backgrounds still remains as one of the most exciting open challenges for theoretical physicists. Among other things, it is important to see how (whether) string theory resolves the cosmological singularities (or not). Some recent attempts along this direction have been made in [1,2,3,4,5,6,7,8,9,10,11,12,13]. In this paper, we investigate the Nappi-Witten (NW) model [14,15] as a conformal field theory (CFT) model that includes big bang and big crunch singularities. This model is defined as an SL(2, R) × SU(2) WZW model gauged by U(1)×U(1) in an asymmetric way. Therefore we can solve it exactly and gain some understanding of the behaviour of strings across these singularities. Similar attempts have been made to understand the cosmological backgrounds by using gauged WZW models, e.g., in [16,17,18,19,20].The NW model describes a four dimensional anisotropic universe that starts at a big bang singularity, expands for a while, ends at a big crunch singularity within a finite affine time, and again starts at another big bang singularity. It was argued in [15] that strings across these singularities make sense because the theory is defined as a coset CFT.This may be related to the fact that strings have a finite length scale l s and may go through the singularities. As described in [15], the coset contains, in addition to copies of the cosmological regions, non-compact and time independent (static) regions known as whiskers. The whisker part of the full space-time contains closed time-like curves (CTCs), which seems to be unacceptable for any measurable quantity like S-matrix. Nevertheless, these CTCs are argued to be necessary for defining the observables in terms of gauged WZW model [15].Hence we would like to ask a question, whether studying the dynamics of D-branes sheds more lights on the understanding of big bang/big crunch singularities and CTCs. This is a non-trivial question because the D-branes, or the open strings ending on them, feel the background geometry in a different way. In particular, D0-brane is an useful candidate to probe the singularities, because the point particle could probe directly the singular points. In fact, the singularities are at strong coupling reg...

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“…A large number of supersymmetric or nonsupersymmetric Gödel-like solutions, including also black holes and time machines, with naked CTCs were constructed in gauged supergravities in higher dimensions, see e.g. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. This work raises important issues of whether the problems of CTCs may be resolved by stringy or quantum considerations, or whether naked CTCs in the bulk implt the breakdown of unitarity of the field theory.…”

Section: Introductionmentioning

confidence: 99%

Gödel universe from string theory

Feng

Hao

et al. 2017

Eur. Phys. J. C

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The Gödel universe is a direct product of a line and a three-dimensional spacetime we call G α . In this paper, we show that the Gödel metrics can arise as exact solutions in Einstein-Maxwell-Axion, Einstein-Proca-Axion, or Freedman-Schwarz gauged supergravity theories. The last option allows us to embed the Gödel universe in string theory. The ten-dimensional spacetime is a direct product of a line and the nine-dimensional one of an S 3 × S 3 bundle over G α , and it can be interpreted as some decoupling limit of the rotating D1/D5/D5 intersection. For some appropriate parameter choice, the nine-dimensional metric becomes an AdS 3 × S 3 bundle over squashed 3-sphere. We also study the properties of the Gödel black holes that are constructed from the double Wick rotations of the Gödel metrics.

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Boundary states for supertubes in flat spacetime and Gödel universe

Cited by 25 publications

References 45 publications

Tunnelling from Gödel black holes

Tunnelling from Gödel black holes

D-branes in a big bang/big crunch universe: Nappi-Witten gauged WZW model

Gödel universe from string theory

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