# String Seminars

This series consists of talks in the area of Superstring Theory.

## Seminar Series Events/Videos

Currently there are no upcoming talks in this series.

## Stringy Instantons, Geometric Transitions, and Dynamical SUSY Breaking

Tuesday Nov 20, 2007

We describe simple systems where stringy instantons induce dynamical supersymmetry breaking, without any non-Abelian gauge dynamics. In suitable cases, a dual description via geometric transitions allows one to recast the instanton-generated superpotential as a classical flux superpotential. These simple DSB systems may have applications in model building.

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## 3d ADS/CFT from a quantum gravity point of view.

Tuesday Nov 13, 2007
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TBA

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## Partition Functions of Three Dimensional Gravity

Monday Nov 12, 2007
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We consider pure three dimensional quantum gravity with a negative cosmological constant. The torus partition function can be computed exactly as a sum over geometries, including all known quantum corrections. The answer provides important clues about the structure of quantum gravity; in particular, in order for the theory to be a proper quantum mechanical system some extra ingredients are needed beyond the usual real geometries considered in general relativity.

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## The Central Charge of AdS2 Gravity

Monday Nov 12, 2007

TBA

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## Sweet spot supersymmetry

Tuesday Nov 06, 2007
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We find that there is no supersymmetric flavor/CP problem, mu-problem, cosmological moduli/gravitino problem or dimension four/five proton decay problem in a class of supersymmetric theories with O(1) GeV gravitino mass. The cosmic abundance of the non-thermally produced gravitinos naturally explains the dark matter component of the universe.

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## Wilson loops in 4d SYM, in 2d YM and in 0d

Tuesday Oct 30, 2007
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I will present a construction of supersymmetric Wilson loop operators in N=4 SYM for an arbitrary path on an S3 subspace of space-time. I will show how they are evaluated in AdS and in particular that the string world-sheet is a generalized calibration with respect to an almost-complex structure associate to the supersymmetries preserved by the loop. I will present some special examples and in the case when the loop is restricted to an S2, some evidence that the calculation reduces to a perturbative calculation in YM in 2-dimensions on S2.

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## Theory of the Nernst effect near quantum phase transitions in condensed matter, and in dyonic black holes

Tuesday Oct 23, 2007
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We present a general hydrodynamic theory of transport in the vicinity of superfluid-insulator transitions in two spatial dimensions described by Lorentz\'\'-invariant quantum critical points. We allow for a weak impurity scattering rate, a magnetic field $B$, and a deviation in the density, $rho$, from that of the insulator.

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## The Atomic Picture of Extremal Black Holes

Tuesday Oct 23, 2007
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Resent research seems to indicate that charged extremal black holes in D=4 supersymmetric theories should be most naturally described in terms of more primitive atomic constituents. I will briefly describe what I mean by these atomic constituents and how they appear to play a role in both BPS and non-BPS extremal black holes.

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## Nonperturbative effects in matrix models and topological strings

Tuesday Oct 16, 2007
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It has been known for a long time that instanton effects control the large order behavior of the perturbation series in quantum mechanics and gauge theories. I present a study of this connection in the context of matrix models in 1/N-expansion and topological strings.

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## Multiloop Gluon Amplitudes and AdS/CFT

Tuesday Oct 02, 2007
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Some recent investigations into the structure of the AdS/CFT correspondence rely on input from increasingly complicated technical calculations. Two related examples in planar N=4 super Yang-Mills theory include testing consequences of integrability and exploring iteration relations amongst multiloop gluon scattering amplitudes. I will review the latest developments in these areas and the methods used to carry out relevant calculations through four loops.

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