arXiv subjects

Andrew Strominger

Publications and source records attributed to Andrew Strominger.

At least 145 records · Page 8Linked to original sources

arXiv2006

D0-branes in Black Hole Attractors

Configurations of N probe D0-branes in a Calabi-Yau black hole are studied. A large degeneracy of near-horizon bound states are found which can be described as lowest Landau levels tiling the horizon of the black hole. These states preserve some of the enhanced supersymmetry of the near-horizon AdS_2xS^2xCY attractor geometry, but not of the full asymptotically flat solution. Supersymmetric non-abelian configurations are constructed which, via the Myers effect, develop charges associated with higher-dimensional branes wrapping CY cycles. An SU(1,1|2) superconformal quantum mechanics describing D0-branes in the attractor geometry is explicitly constructed.

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arXiv2006

From AdS3/CFT2 to Black Holes/Topological Strings

The elliptic genus Z_{BH} of a large class of 4D black holes can be expressed as an M-theory partition function on an AdS_3xS^2xCY_3 attractor. We approximate this partition function by summing over multiparticle chiral primary states of membranes which wrap curves in the CY_3 and tile Landau levels on the horizon S^2. Significantly, membranes and antimembranes can preserve the same supercharges if they occupy antipodal points on the horizon. It is shown the membrane contribution to Z_{BH} gives precisely the topological string partition function Z_{top} while the antimembranes give \bar Z_{top}, implying Z_{BH}=|Z_{top}|^2 in this approximation.

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arXiv2006

5D Black Rings and 4D Black Holes

It has recently been shown that the M theory lift of a IIA 4D BPS Calabi-Yau black hole is a 5D BPS black hole spinning at the center of a Taub-NUT-flux geometries, and a certain linear relation between 4D and 5D BPS partition functions was accordingly proposed. In the present work we fortify and enrich this proposal by showing that the M-theory lift of the general 4D multi-black hole geometry are 5D black rings in a Taub-NUT-flux geometry.

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arXiv2005

D4-D0 Branes on the Quintic

It is proposed that the quantum mechanics of N D4-branes and M D0-branes on the quintic is described by the dimensional reduction of a certain U(N)xU(M) quiver gauge theory, whose superpotential encodes the defining quintic polynomial. It is shown that the moduli space on the Higgs branch exactly reproduces the moduli space of degree N hypersurfaces in the quintic endowed with the appropriate line bundle, and that the cohomology growth reproduces the D4-D0 black hole entropy.

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arXiv2005

Counting Dyons in N=8 String Theory

A recently discovered relation between 4D and 5D black holes is used to derive exact (weighted) BPS black hole degeneracies for 4D N=8 string theory from the exactly known 5D degeneracies. A direct 4D microscopic derivation in terms of weighted 4D D-brane bound state degeneracies is sketched and found to agree.

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arXiv2005

R^2 Corrections for 5D Black Holes and Rings

We study higher-order corrections to two BPS solutions of 5D supergravity, namely the supersymmetric black ring and the spinning black hole. Due in part to our current relatively limited understanding of F-type terms in 5D supergravity, the nature of these corrections is less clear than that of their 4D cousins. Effects of certain $R^2$ terms found in Calabi-Yau compactification of M-theory are specifically considered. For the case of the black ring, for which the microscopic origin of the entropy is generally known, the corresponding higher order macroscopic correction to the entropy is found to match a microscopic correction, while for the spinning black hole the corrections are partially matched to those of a 4D $D0-D2-D6$ black hole.

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arXiv2004

Superconformal Black Hole Quantum Mechanics

In recent work, the superconformal quantum mechanics describing D0 branes in the AdS_2xS^2xCY_3 attractor geometry of a Calabi-Yau black hole with D4 brane charges p^A has been constructed and found to contain a large degeneracy of chiral primary bound states. In this paper it is shown that the asymptotic growth of chiral primaries for N D0 branes exactly matches the Bekenstein-Hawking area law for a black hole with D4 brane charge p^A and D0 brane charge N. This large degeneracy arises from D0 branes in lowest Landau levels which tile the CY_3xS^2 horizon. It is conjectured that such a multi-D0 brane CFT1 is holographically dual to IIA string theory on AdS_2xS^2xCY_3.

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arXiv2004

Microscopic Entropy of the Black Ring

A surprising new seven-parameter supersymmetric black ring solution of five-dimensional supergravity has recently been discovered. In this paper, M-theory is used to give an exact microscopic accounting of its entropy.

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arXiv2004

Black Hole Non-Formation in the Matrix Model

The leading classical low-energy effective actions for two-dimensional string theories have solutions describing the gravitational collapse of shells of matter into a black hole. It is shown that string loop corrections can be made arbitrarily small up to the horizon, but $α'$ corrections cannot. The matrix model is used to show that typical collapsing shells do not form black holes in the full string theory. Rather, they backscatter out to infinity just before the horizon forms. The matrix model is also used to show that the naively expected particle production induced by the collapsing shell vanishes to leading order. This agrees with the string theory computation. From the point of view of the effective low energy field theory this result is surprising and involves a delicate cancellation between various terms.

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arXiv2004

Supersymmetric Branes in AdS_2 x S^2 x CY_3

The problem of finding supersymmetric brane configurations in the near-horizon attractor geometry of a Calabi-Yau black hole with magnetic-electric charges (p^I,q_I) is considered. Half-BPS configurations, which are static for some choice of global AdS2 coordinate, are found for wrapped brane configurations with essentially any four-dimensional charges (u^I,v_I). Half-BPS multibrane configurations can also be found for any collection of wrapped branes provided they all have the same sign for the symplectic inner product p^Iv_I-u^Iq_I of their charges with the black hole charges. This contrasts with the Minkowski problem for which a mutually preserved supersymmetry requires alignment of all the charge vectors. The radial position of the branes in global AdS2 is determined by the phase of their central charge.

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arXiv2004

Black Hole Attractors and the Topological String

A simple relationship of the form Z_BH = |Z_top|^2 is conjectured, where Z_BH is a supersymmetric partition function for a four-dimensional BPS black hole in a Calabi-Yau compactification of Type II superstring theory and Z_top is a second-quantized topological string partition function evaluated at the attractor point in moduli space associated to the black hole charges. Evidence for the conjecture in a perturbation expansion about large graviphoton charge is given. The microcanonical ensemble of BPS black holes can be viewed as the Wigner function associated to the wavefunction defined by the topological string partition function.

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arXiv2004

Closed String Tachyon Condensation at c=1

The c=1 matrix model, with or without a type 0 hat, has an exact quantum solution corresponding to closed string tachyon condensation along a null surface. The condensation occurs, and spacetime dissolves, at a finite retarded time on I^+. The outgoing quantum state of tachyon fluctuations in this time-dependent background is computed using both the collective field and exact fermion pictures. Perturbative particle production induced by the moving tachyon wall is shown to be similar to that induced by a soft moving mirror. Hence, despite the fact that I^+ for the tachyon is geodesicaly incomplete, quantum correlations in the incoming state are unitarily transmitted to the outgoing state in perturbation theory. It is also shown that, non-perturbatively, information can leak across the tachyon wall, and tachyon scattering is not unitary. Exact unitarity remains intact only in the free fermion picture.

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arXiv2004

Hartle-Hawking Vacuum for c=1 Tachyon Condensation

Quantum vacua are constructed for a time-symmetric cosmology describing closed string tachyon condensation in two-dimensional string theory. Due to the Euclidean periodicity of the solution, and despite its time dependence, we are able to construct thermal states at discrete values of the temperature. The asymptotic thermal Green functions and stress energy tensor are computed and found to have an intriguing resemblance to those in the Hartle-Hawking vacuum of a black hole.

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arXiv2004

An Index for 2D field theories with large N=4 superconformal symmetry

We consider families of theories with large N=4 superconformal symmetry. We define an index generalizing the elliptic genus of theories with N=2 symmetry. In contrast to the N=2 case, the new index constrains part of the non-BPS spectrum. Motivated by aspects of the AdS/CFT correspondence we study the index in the examples of symmetric product theories. We give a physical interpretation of the Hecke operators which appear in the expressions for partition functions of such theories. Finally, we compute the index for a nontrivial example of a symmetric product theory.

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arXiv2004

The Search for a Holographic Dual to AdS(3)xS(3)xS(3)xS(1)

The problem of finding a holographic CFT dual to string theory on AdS(3)xS(3)xS(3)xS(1) is examined in depth. This background supports a large N=4 superconformal symmetry. While in some respects similar to the familiar small N=4 systems on AdS(3)xS(3)xK3 and AdS(3)xS(3)xT4, there are important qualitative differences. Using an analog of the elliptic genus for large N=4 theories we rule out all extant proposals -- in their simplest form -- for a holographic duality to supergravity at generic values of the background fluxes. Modifications of these extant proposals and other possible duals are discussed.

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arXiv2004

Chern-Simons Gauge Theory and the AdS(3)/CFT(2) Correspondence

The bulk partition function of pure Chern-Simons theory on a three-manifold is a state in the space of conformal blocks of the dual boundary RCFT, and therefore transforms non-trivially under the boundary modular group. In contrast the bulk partition function of AdS(3) string theory is the modular-invariant partition function of the dual CFT on the boundary. This is a puzzle because AdS(3) string theory formally reduces to pure Chern-Simons theory at long distances. We study this puzzle in the context of massive Chern-Simons theory. We show that the puzzle is resolved in this context by the appearance of a chiral "spectator boson" in the boundary CFT which restores modular invariance. It couples to the conformal metric but not to the gauge field on the boundary. Consequently, we find a generalization of the standard Chern-Simons/RCFT correspondence involving "nonholomorphic conformal blocks" and nonrational boundary CFTs. These generalizations appear in the long-distance limit of AdS(3) string theory, where the role of the spectator boson is played by other degrees of freedom in the theory.

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arXiv2004

Non-Singular Solutions for S-branes

Exact, non-singular, time-dependent solutions of Maxwell-Einstein gravity with and without dilatons are constructed by double Wick rotating a variety of static, axisymmetric solutions. This procedure transforms arrays of charged or neutral black holes into s-brane (spacelike brane) solutions, i.e. extended, short-lived spacelike defects. Along the way, new static solutions corresponding to arrays of alternating-charge Reissner-Nordstrom black holes, as well as their dilatonic generalizations, are found. Their double Wick rotation yields s-brane solutions which are periodic in imaginary time and potential large-N duals for the creation/decay of unstable D-branes in string theory.

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arXiv2003

Correlators in Timelike Bulk Liouville Theory

Liouville theory with a negative norm boson and no screening charge corresponds to an exact classical solution of closed bosonic string theory describing time-dependent bulk tachyon condensation. A simple expression for the two point function is proposed based on renormalization/analytic continuation of the known results for the ordinary (positive-norm) Liouville theory. The expression agrees exactly with the minisuperspace result for the closed string pair-production rate (which diverges at finite time). Puzzles concerning the three-point function are presented and discussed.

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