This series consists of talks in the area of Superstring Theory.
I
will discuss superhorizon fluctuations in de Sitter space. The first part of
the talk will focus on computing entanglement entropies of field theories in a
fixed de Sitter background. Those computations are done for free theories and
also theories with gravity duals. If time permits, I will also discuss
superhorizon fluctuations in cosmological backgrounds. In particular, I focus
on showing that subhorizon fluctuations can not produce any significant
backreaction on superhorizon modes. If those late time effects existed, one in
The study of the worldsheet S-matrix for AdS_5×S^5
strings was a key step in
the complete determination of the non-pertubrative planar
spectrum of anomalous
dimensions for N=4 super-Yang-Mills. To go beyond
the spectral problem it is
important to consider higher-point
worldsheet correlation functions and, as is
standard in many integrable models, one approach is
the study of form factors.
We will discuss a set of consistency conditions appropriate
to form factors in
In this talk we will present results on all one-loop scattering amplitudes in N=6 Chern-Simons matter theories. Especially we will discuss connection between certain triple-cut diagrams and tree-level recursive diagrams, and a general formula capturing the multi-particle factorization of arbitrary one-loop amplitudes in the theories is obtained from this connection. Furthermore a recursion relation for the supercoefficients of one-loop amplitudes will be derived, which leads the solution for all one-loop amplitudes.
Two-dimensional gauge
theories with (0,2) supersymmetry admit a much broader, and more interesting,
class of solutions than their better studied (2,2) counterparts. In this talk,
we will explore some of the possibilities that are offered by this additional
freedom. The moduli spaces we find can be interpreted as the target spaces for
heterotic strings moving in backgrounds with non-trivial H-flux. A remarkable
relationship between (0,2) gauge anomalies and H-flux will emerge.
The information paradox and the infall problem have been
long-standing puzzles in the understanding of black holes. The idea of free
infall is in considerable tension with unitarity of the evaporation process and
recent developements have made this tension sharp. In the first part of my talk
I will address the information question and argue that unitarty requires every
quantum of radiation leaving the black hole to carry information about the
initial state. Unitary evaporation is thus inconsistent with an
Warped AdS3 has isometry SL(2,R) x U(1). It is closed
related to Kerr/CFT, non local dipole theories and AdS/CMT. In this talk I will
derive the spectrum of string theory on
Warped AdS3. This is possible because the worldsheet theory can be
mapped to the worldsheet on AdS3 by a nonlocal field redefinition.
In this talk, I will
relate moduli stabilization in AdS or de Sitter space to basic properties of
the Wilsonian action in the holographic dual theory living on dS (of one lower
dimension): the single-trace terms in the action have vanishing beta
functions, and higher-trace couplings are determined purely from lower-trace
ones (a property we refer to as the iterative structure of RG). In the dS
case, this encodes the maximal symmetry of the bulk spacetime in a quantity
which is accessible within a single observer's patch.
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
dualities.
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
develop the Extremal Functional Method (EFM), a numerical procedure for
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