Publications (48)250.4 Total impact
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ABSTRACT: We use Hamiltonian methods to study curved domain walls and cosmologies. This leads naturally to firstorder equations for all domain walls and cosmologies foliated by slices of maximal symmetry. For Minkowski and AdSsliced domain walls (flat and closed FLRW cosmologies) we recover a recent result concerning their (pseudo)supersymmetry. We show how domainwall stability is consistent with the instability of AdS vacua that violate the BreitenlohnerFreedman bound. We also explore the relationship to HamiltonJacobi theory and compute the wavefunction of a 3dimensional closed universe evolving towards de Sitter spacetime.Physical Review D 12/2006; 74:125008. · 4.86 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: The correspondence between domainwall and cosmological solutions of gravity coupled to scalar fields is explained. Any domain wall solution that admits a Killing spinor is shown to correspond to a cosmology that admits a pseudoKilling spinor: whereas the Killing spinor obeys a Diractype equation with hermitian `mass'matrix, the corresponding pseudoKilling spinor obeys a Diractype equation with a antihermitian `mass'matrix. We comment on some implications of (pseudo)supersymmetry.Journal of Physics A Mathematical and Theoretical 11/2006; 40(25). DOI:10.1088/17518113/40/25/S18 · 1.58 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: The (2k+2)dimensional EinsteinYangMills equations for gauge group SO(2k) (or SU(2) for k=2 and SU(3) for k=3) are shown to admit a family of sphericallysymmetric magnetic monopole solutions, for both zero and nonzero cosmological constant Lambda, characterized by a mass m and a magnetictype charge. The k=1 case is the ReissnerNordstrom black hole. The k=2 case yields a family of selfgravitating Yang monopoles. The asymptotic spacetime is Minkowski for Lambda=0 and antide Sitter for Lambda<0, but the total energy is infinite for k>1. In all cases, there is an event horizon when m>m_c, for some critical mass $m_c$, which is negative for k>1. The horizon is degenerate when m=m_c, and the nearhorizon solution is then an adS_2 x S^{2k} vacuum. Comment: 16 pp. Extensive revision to include case of nonzero cosmological constant and implications for adS/CFT. Numerous additional referencesClassical and Quantum Gravity 04/2006; 23(15). DOI:10.1088/02649381/23/15/007 · 3.17 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We argue that the WessZumino model with quartic superpotential admits stable static solutions in which three domain walls intersect at a junction. We derive an energy bound for such junctions and show that configurations saturating it preserve 14 supersymmetry.Physical Review Letters 08/1999; 83(9):17271730. DOI:10.1103/PhysRevLett.83.1727 · 7.51 Impact Factor 
Article: The Manifestly
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ABSTRACT: We present a manifestly Sl(2; Z)covariant action for the type IIB superstring, and prove symmetry for onshell IIB supergravity backgrounds. 1. Introduction The Type IIB superstring theory has D=10 IIB supergravity as its effective field theory. Until a few years ago, the Sl(2; R) invariance of the latter [1,2] was thought to be an artefact of the field theory approximation to string theory, but it is now believed that IIB superstring theory is itself an approximation to some underlying nonperturbative theory in which an Sl(2; Z) subgroup of Sl(2; R) survives as a symmetry [3,4]. To the extent to which this theory can be said to be a string theory it describes an entire Sl(2; Z) orbit of `(p; q)' strings [5,6] with the (1,0) string being the GreenSchwarz (GS) IIB superstring and the (0,1) string the Dstring. This explains why both the usual IIB superstring action, and that of the Dstring, break Sl(2; Z) (the action for the `fundamental' string breaks the full group, while the ...  [Show abstract] [Hide abstract]
ABSTRACT: A static minimal energy configuration of a super pbrane in a supersymmetric (n+1)dimensional spacetime is shown to be a `generalized calibrated' submanifold. Calibrations in $\bE^{(1,n)}$ and $AdS_{n+1}$ are special cases. We present several Mbrane examples. Comment: Revtex. 11 pp. Minor corrections made and references added. To appear in Phys. Rev. DPhysical Review D 05/1999; 60(10). DOI:10.1103/PhysRevD.60.106006 · 4.64 Impact Factor 
Article: Black Holes and Calogero Models
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ABSTRACT: We argue that the large n limit of the nparticle SU(1,12) superconformal Calogero model provides a microscopic description of the extreme Reissner–Nordström black hole in the nearhorizon limit.Physics Letters B 12/1998; 454(34454):187192. DOI:10.1016/S03702693(99)00266X · 6.13 Impact Factor 
Article: Black Holes of D=5 Supergravity
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ABSTRACT: We discuss some general features of black holes of fivedimensional supergravity, such as the first law of black hole mechanics. We also discuss some special features of rotating supersymmetric black holes. In particular, we show that the horizon is a nonsingular, and {\sl nonrotating}, null hypersurface whose intersection with a Cauchy surface is a squashed 3sphere. We find the Killing spinors of the nearhorizon geometry and thereby determine the nearhorizon isometry supergroup.Classical and Quantum Gravity 11/1998; 16(1). DOI:10.1088/02649381/16/1/001 · 3.17 Impact Factor 
Article: Supersymmetry of rotating branes
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ABSTRACT: We present a new 1/8 supersymmetric intersecting Mbrane solution of D=11 supergravity with two independent rotation parameters. The metric has a nonsingular event horizon and the nearhorizon geometry is AdS3×S3×S3×E2 (just as in the nonrotating case). We also present a method of determining the isometry supergroup of supergravity solutions from the Killing spinors and use it to show that for the near horizon solution it is D(21,α)×D(21,α) where α is the ratio of the two 3sphere radii. We also consider various dimensional reductions of our solution, and the corresponding effect of these reductions on the Killing spinors and the isometry supergroups.Physical Review D 11/1998; 59(2). DOI:10.1103/PhysRevD.59.025001 · 4.64 Impact Factor 
Article: M(embrane) theory on T9
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ABSTRACT: An ‘algebraic’ approach to Mtheory is briefly reviewed, and a proposal is made for a similar algebraic structure underlying the T9 compactification of ‘M(embrane) theory’, i.e. the M(atrix) model with areapreserving diffeomorphism gauge group.Nuclear Physics B  Proceedings Supplements 11/1998; 68(168):1116. DOI:10.1016/S09205632(98)001364 · 0.88 Impact Factor 
Article: Mbranes at angles
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ABSTRACT: Supersymmetric configurations of nonorthogonally intersecting M5branes can be obtained by rotation of one of a pair of parallel M5branes. Examples preserving and supersymmetry are reviewed.Nuclear Physics B  Proceedings Supplements 07/1998; 67(1367):8892. DOI:10.1016/S09205632(98)001248 · 0.88 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We derive a bound on the energy of the general (p, q)supersymmeric twodimensional massive sigmamodel with torsion, in terms of the topological and Noether charges that appear as central charges in its supersymmetry algebra. The bound is saturated by soliton solutions of firstorder Bogomol'nyitype equations. This generalizes results obtained previously for p = q models without torsion. We give examples of massive (1, 1) models with torsion that have a group manifold as a target space. We show that they generically have multiple vacua and find an explicit soliton solution of an SU(2) model. We also construct a new class of zerotorsion massive (4, 4) models with multiple vacua and soliton solutions. In addition, we compute the metrics on the onesoliton moduli spaces for those cases for which soliton solutions are known explicitly, and discuss their interpretation.Nuclear Physics B 06/1998; 444(1444):245264. DOI:10.1016/05503213(95)00125C · 3.93 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: It is argued that the type IIA 10dimensional superstring theory is actually a compactified 11dimensional supermembrane theory in which the fundamental supermembrane is identified with the soltionic membrane of 11dimensional supergravity. The charged extreme black holes of the 10dimensional type IIA string theory are interpreted as the KaluzaKlein modes of 11dimensional supergravity and the dual sixbranes as the analogue of KaluzaKlein monopoles. All other pbrane solutions of the type IIA superstring theory are derived from the 11dimensional membrane and its magnetic dual fivebrane soliton.Physics Letters B 06/1998; 350(2350):184188. DOI:10.1016/03702693(95)003974 · 6.13 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: Generalized membrane solutions of D = 11 supergravity, for which the transverse space is a toric hyperKahler manifold, are shown to have IIB duals representing the intersection of parallel 3branes with 5branes whose orientations are determined by their charge vectors. These IIB solutions, which generically preserve 3/16 of the supersymmetry, can be further mapped to solutions of D = 11 supergravity representing the intersection of parallel membranes with any number of fivebranes at arbitrary angles. Alternatively, a subclass (corresponding to nonsingular D = 11 solutions) can be mapped to solutions representing the intersection on a string of any number of D5branes at arbitrary angles, again preserving supersymmetry, as we verify in a special case by a quaternionic extension of the analysis of Berkooz, Douglas and Leigh. We also use similar methods to find new supersymmetric solutions of orthogonally intersecting branes.Nuclear Physics B 09/1997; 500(13500):133162. DOI:10.1016/S05503213(97)003350 · 3.93 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We present a manifestly Sl(2; Z)covariant action for the type IIB superstring, and prove symmetry for onshell IIB supergravity backgrounds. 1. Introduction The Type IIB superstring theory has D=10 IIB supergravity as its effective field theory. Until a few years ago, the Sl(2; R) invariance of the latter [1,2] was thought to be an artefact of the field theory approximation to string theory, but it is now believed that IIB superstring theory is itself an approximation to some underlying nonperturbative theory in which an Sl(2; Z) subgroup of Sl(2; R) survives as a symmetry [3,4]. To the extent to which this theory can be said to be a string theory it describes an entire Sl(2; Z) orbit of `(p; q)' strings [5,6] with the (1,0) string being the GreenSchwarz (GS) IIB superstring and the (0,1) string the Dstring. This explains why both the usual IIB superstring action, and that of the Dstring, break Sl(2; Z) (the action for the `fundamental' string breaks the full group, while the ...Journal of High Energy Physics 08/1997; 1997(09). DOI:10.1088/11266708/1997/09/003 · 6.11 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: A manifestly Sdual, and ‘12 dimensional’, IIB superstring action with an Sl(2; ) doublet of ‘BornInfeld’ fields is presented. The Mtheory origin of the 12th dimension is the M2brane tension, which can be regarded as the flux of a 3form worldvolume field strength. The latter is required by the fact that the M2brane can have a boundary on an M5brane.Physics Letters B 05/1997; 409(14409):131135. DOI:10.1016/S03702693(97)008629 · 6.13 Impact Factor 
Article: KaluzaKlein on the brane
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ABSTRACT: The Mtheory interpretation of certain D = 10 IIA pbranes implies the existence of worldvolume KaluzaKlein modes which are expected to appear as 0brane/pbrane bound states preserving of the spacetime supersymmetry. We construct the corresponding solutions of the effective supergravity theory for p = 1,4, and show that no such solution exists for p = 8.Physics Letters B 09/1996; 393(12393):5964. DOI:10.1016/S03702693(96)016140 · 6.13 Impact Factor 
Article: Intersecting Mbranes
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ABSTRACT: We present the magnetic duals of Güven's electrictype solutions of D = 11 supergravity preserving or of the D = 11 supersymmetry. We interpret the electric solutions as n orthogonal intersecting membranes and the magnetic solutions as n orthogonal intersecting 5branes, with n = 2, 3; these cases obey the general rule that pbranes can selfintersect on (p − 2)branes. On reduction to D = 4 these solutions become electric or magnetic dilaton black holes with dilaton coupling constant a = 1 (for n = 2) or (for n = 3). We also discuss the reduction to D = 10.Physics Letters B 03/1996; 380(34380):273279. DOI:10.1016/03702693(96)005060 · 6.13 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: A review is given of the implications of supersymmetric black holes for the nonperturbative formulation of toroidally compactified superstrings, with particular emphasis on symmetry enhancement at special vacua and Sduality of the heterotic string.Nuclear Physics B  Proceedings Supplements 10/1995; 45(2345):188195. DOI:10.1016/09205632(95)006362 · 0.88 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We investigate the compactification of D = 11 supergravity to D = 5,4,3, on compact manifolds of holonomy SU(3) (CalabiYau), G2, and Spin(7), respectively, making use of examples of the latter two cases found recently by Joyce. In each case the lower dimensional theory is a Maxwell/Einstein supergravity theory. We find evidence for an equivalence, in certain cases, with heterotic string compactifications from D = 10 to D = 5,4,3, on compact manifolds of holonomy SU(2) (K3 × S1), SU(3), and G2, respectively. CalabiYau manifolds with Hodge numbers h1,1 = h1,2 = 19 play a significant role in the proposed equivalences.Physics Letters B 06/1995; 357(3357):300306. DOI:10.1016/03702693(95)00929F · 6.13 Impact Factor
Publication Stats
4k  Citations  
250.40  Total Impact Points  
Top Journals
Institutions

19862006

University of Cambridge
 Department of Applied Mathematics and Theoretical Physics
Cambridge, England, United Kingdom


1993

University of California, Santa Barbara
 Kavli Institute for Theoretical Physics
Santa Barbara, California, United States
