1,721,029 research outputs found
How much can supergravity teach us about microscopic features of BPS black holes?
No full textWe review recent results in the study of regular four dimensional BPS black holes in toroidally compactified type II (or M) theory. We discuss the generating solution for this kind of black holes, its microscopic description(s), and compute the corresponding microscopic entropy. These achievements, which provide a description of the fundamental degrees of freedom accounting for the entropy of any regular BPS black hole in the theory under consideration, are inscribed within a research project aimed to the study of the microscopic properties of this kind of solutions in relation to U--duality invariants computed on the corresponding macroscopic (supergravity) description
The Generating solution of regular N=8 BPS black holes
No full textIn this paper we construct the five-parameter generating solution of N = 8 BPS regular supergravity black holes as a five-parameter solution of the N = 2 STU model. Our solution has a simpler form with respect to previous constructions which have already appeared in the literature and moreover, through the embedding [SL(2)](3) subset of SV(3, 3) subset of E-7(7) discussed in previous papers, the action of the U-duality group is well defined. This allows us to reproduce via U-duality rotations any other solution, such as those corresponding to R-R black holes whose microscopic description is given by intersecting D-branes
The Role of PSL(2, 7) in M‐theory: M2‐Branes, Englert Equation and the Septuples
Full text linkReconsidering the M2-brane solutions of (Formula presented.) supergravity with a transverse Englert flux introduced by one of us in 2016, we present a new purely group theoretical algorithm to solve Englert equation based on a specific embedding of the PSL(2, 7) group into (Formula presented.). The aforementioned embedding is singled out by the identification of PSL(2, 7) with the automorphism group of the Fano plane. Relying on the revealed intrinsic PSL(2, 7) symmetry of Englert equation and on the new algorithm we present an exhaustive classification of Englert fluxes. The residual supersymmetries of the corresponding M2-brane solutions associated with the first of the 8 classes into which we have partitioned Englert fluxes are exhaustively analyzed and we show that all residual (Formula presented.) supersymmetries with (Formula presented.) are available. Our constructions correspond to a particular case in the category of M2-brane solutions with transverse self-dual fluxes
Instantons and wormholes in AdS(3) x S-3 x CY2
Full text linkWe study supergravity instantons sourced by axion (and saxion) fields in the Euclidean AdS(3) x S-3 x CY2 vacua of IIB supergravity. Such instantons are described by geodesic curves on the moduli space; the timelike geodesics can describe Euclidean wormholes, the lightlike geodesics describe (generalizations of) D instantons, and spacelike geodesics are subextremal versions thereof. We perform a concrete classification of such geodesics and find that, despite earlier claims, the wormholes fail to be regular. A subclass of the lightlike geodesics is supersymmetric and, up to dualities, lifts to Euclidean strings wrapping 2-cycles in the CY2. The dual of these instantons is expected to be worldsheet instantons of the D1-D5 conformal field theory
The holographic dual to supergravity instantons in AdS<sub>5</sub><i>x</i> S<SUP>5</SUP><i>/</i>DOUBLE-STRUCK CAPITAL Z<sub>k</sub>
Full text linksponsorship: We thank Nikolay Bobev for useful discussions. The work of SK is supported by the KU Leuven C1 grant ZKD1118 C16/16/005 and by the Belgian Federal Science Policy Office through the Inter-University Attraction Pole P7/37. The work of TVR is supported by the FWO odysseus grant G.0.E52.14N and by the C16/16/005 grant of the KULeuven. We furthermore acknowledge support from the European Science Foundation Holograv Network and the COST Action MP1210 'The String Theory Universe'. (KU Leuven C1 grant|ZKD1118 C16/16/005, Belgian Federal Science Policy Office through the Inter-University Attraction Pole|P7/37, FWO odysseus grant|G.0.E52.14N, KULeuven|C16/16/005, European Science Foundation Holograv Network, COST Action 'The String Theory Universe'|MP1210)status: Publishe
Regular RR and NS NS BPS black holes
No full textWe show in a precise group theoretical fashion how the generating solution of regular BPS black holes of N = 8 supergravity, which is known to be a solution also of a simpler N = 2 STU model truncation, can be characterized as purely NS-NS or R-R charged according to the way the corresponding STU model is embedded in the original N = 8 theory. Of particular interest is the class of embeddings which yield regular BPS black hole solutions carrying only R-R charge and whose microscopic description can possibly be given in terms of bound states of D-branes only. The microscopic interpretation of the bosonic fields in this class of STU models relies on the solvable Lie algebra (SLA) method. In the present paper, we improve this mathematical technique in order to provide two distinct descriptions for type IIR and type IIB theories and an algebraic characterization of S x T-dual embeddings within the N = 8, d = 4 theory. This analysis will be applied to the particular example of a four parameter (dilatonic) solution of which both the full macroscopic and microscopic descriptions will be worked out
Microscopic entropy of the most general four-dimensional BPS black hole
No full textIn a recent paper we have given the macroscopic and microscopic description of the generating solution of toroidally compactified string theory BPS black holes. In this note we compute its corresponding microscopic entropy. Since by definition the generating solution is the most general solution modulo U-duality transformations, this result accounts for the degeneracy of microstates determining the entropy of any regular BPS black holes of toroidally compactified string (or M) theory
Gauged N=3, D=4 supergravity: A new web of marginally connected vacua
Full text linkWe analyze the vacuum structure of N=3,D=4 supergravity coupled to 9 vector multiplets with gauge group SO(3)×SU(3). Aside from the central N=3 AdS4 vacuum at the origin, on which the supermultiplet structure reproduces the massless sector of M-theory compactified on N0,1,0, we find a rich structure of AdS4 vacua preserving N=0,1,2,3 supersymmetry. These new vacua are arranged in a manifold spanned by scalar fields corresponding to exactly marginal deformations of the dual CFT. This manifold has the form T3/K, where K is a discrete subgroup of the gauge group: N=3,2 and 1 vacua correspond, respectively, to a point, a line and a surface in the three-dimensional vacuum manifold. We study RG flows from the central N=3 vacuum and elaborate on the possible higher dimensional origin of the new vacua. For the reader's convenience we also provide a review of the embedding tensor formulation of D=4, N=3 gauged supergravities. In particular we provide formulas involving the fermion shift tensors and mass matrices in N=3 theories, which can be applied to a generic gauging
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