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.


Wednesday Nov 28, 2012

Chern-Simons contact terms constitute new
observables in three-dimensional quantum field theory. In N=2 supersymmetric
theories with an R-symmetry, they lead to a superconformal anomaly. This
understanding clarifies several puzzles surrounding the S3 partition function
of these theories. In particular, it leads to a proof of the F-maximization
principle.  Chern-Simons contact terms
can be computed exactly using localization and lead to new tests of proposed

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Tuesday Nov 27, 2012

The existence of a
positive linear functional acting on the space of (differences between)
conformal blocks has been shown to rule out regions in the parameter space of
conformal field theories (CFTs). We argue that at the boundary of the allowed
region the extremal functional contains, in principle, enough information to
determine the dimensions and OPE coefficients of an infinite number of
operators appearing in the correlator under analysis. Based on this idea we

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Tuesday Nov 20, 2012

I will present recent developments in the computation of
three point functions in the AdS4/CFT3 correspondence. More specifically I will
consider two different computations for three point functions of operators
belonging to the SU(2)XSU(2) sector of  ABJM. I
will discuss first the generalization of the
determinant representation, found by Foda for the three-point functions of
the SU(2) sector of N = 4 SYM, to the ABJM theory and 

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Tuesday Nov 13, 2012

I will discuss recent progress in the study of
anomaly-induced transport, focusing on the chiral vortical effect in 3+1 dimensions.
Most of my discussion will be framed in light of a larger story, namely
progress in making exact statements about finite-temperature quantum field
theory, for which the chiral magnetic and vortical effects are instructive

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Tuesday Nov 06, 2012

Recently techniques have been developed to compute the
partition functions of 3d theories with N=2 supersymmetry on curved, compact
spaces, in particular S^3 and S^2xS^1 (the latter giving a supersymmetric
index). I will discuss how both of these partition functions can be decomposed
as products of more fundamental, universal "holomorphic blocks." For
3d gauge theories arising from (auxiliary) 3-manifolds M, these holomorphic
blocks are specific Chern-Simons partition functions on M.

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Tuesday Oct 23, 2012

String-like objects arise in many quantum field theories.
Well known examples include flux tubes in QCD and cosmic strings. To a first approximation,
their dynamics is governed by the Nambu-Goto action, but for QCD flux tubes
numerical calculations of the energy levels of these objects have become so
accurate that a systematic understanding of corrections to this simple
description is desirable.

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Tuesday Oct 16, 2012

The entanglement entropy S(R) across a circle of radius R
has been invoked recently in deriving general constraints on renormalization
group flow in three-dimensional field theory. 
At conformal fixed points, the negative of the finite part of the
entanglement entropy, which is called F, is equal to the free energy on the
round three-sphere. The F-theorem states that F decreases under RG flow.

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Tuesday Oct 09, 2012

Integrability has been successfully used to compute the
non-perturbative spectrum, Wilson loops and scattering amplitudes in the
AdS/CFT correspondence. Most of these results apply to N=4, D=4 SYM / strings
on AdS(5)xS(5). Strings on AdS(3)xM, where M is either



Tuesday Sep 25, 2012

We derive the collective theory of singlet fields of large-N Sp(N) spin
models and display its unconventional features. Using the known relationship
between O(N) collective fields and higher spin fields of Vasiliev theory in AdS
space, we argue that the unique features of the Sp(N) collective
theory suggest an interpretation in terms of a higher spin theory in de Sitter
space, as proposed by Anninos, Hartman and Strominger.  This is
reminiscent of the way the Liouville mode is naturally  interpreted as



Tuesday Sep 11, 2012

When nuclear matter is heated beyond a temperature of 2 trillion

degrees, it converts into a strongly coupled plasma of quarks and

gluons, the sQGP. Experiments using highly energetic collisions

between heavy nuclei have revealed that this new state of matter is a

nearly ideal, highly opaque liquid. A description based upon string

theory and black holes in five dimensions has made the quark- gluon

plasma an iconic example of a strongly coupled quantum system. In this

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