Evgeny Skvortsov

9/28/16, 2:00 PM

String & Mathematical Physics

We study the higher-spin gauge theory in six-dimensional anti-de Sitter space AdS6 that is based on the exceptional Lie superalgebra F(4). The relevant higher-spin algebra was constructed in arXiv:1409.2185 [hep-th]. We determine the spectrum of the theory and show that it contains the physical fields of the Romans F(4) gauged supergravity. The full spectrum consists of an infinite tower of...

Dr
Dmitri Bykov
(Max-Planck-Institut fur Gravitationsphysik)

9/28/16, 2:20 PM

String & Mathematical Physics

We construct zero-curvature representations for the equations of motion of a class of sigma-models with complex homogeneous target spaces, not necessarily symmetric. We show that in the symmetric case the proposed flat connection is gauge-equivalent to the conventional one.

Jochen Zahn
(Universität Leipzig)

9/28/16, 2:40 PM

String & Mathematical Physics

In the sense of perturbation theory around arbitrary classical solutions, the Nambu-Goto (NG) string can be consistently quantised as an effective theory for any dimension $D$ of the target space [Comm. Math. Phys. 327 (2014) 779, with D. Bahns & K. Rejzner]. In this framework, we compute semi-classical corrections to the energy of rotating NG strings, using the locally covariant...

Burkhard Eden

9/28/16, 3:00 PM

String & Mathematical Physics

Three-point functions of generic gauge invariant composite operators in N=4 SYM are very hard to construct in higher-order weak-coupling perturbation theory. On the other hand, three-point functions of half-BPS operators are non-renormalised, and guided by symmetry principles the integrands for their four-point functions can be constructed to high loop order at least in the planar theory. We...

Mr
Severin Lüst
(Universität Hamburg)

9/28/16, 3:20 PM

String & Mathematical Physics

We study maximally supersymmetric solutions of all gauged or deformed supergravity theories in D≥3 space-time dimensions. For vanishing background fluxes the space-time background has to be either Minkowski or anti-de Sitter. We derive a simple criterion for the existence of solutions with non-trivial fluxes and determine all supergravities that satisfy it. We show that their solutions...

Paul-Konstantin Oehlmann
(DESY)

9/28/16, 3:35 PM

String & Mathematical Physics

We give further evidence that genus-one fibers with multi-sections are mirror dual to fibers with Mordell-Weil torsion. In the physics of F-theory compactifications this implies a relation between models with a non-simply connected gauge group and those with discrete symmetries. We explicitly check this observation for torus fibers in two and three dimensional ambient spaces whereas the...

Dr
Irene Valenzuela
(MPI, Munich)

9/28/16, 4:15 PM

String & Mathematical Physics

Axion monodromy is a promising proposal to achieve a transplanckian field range for an axion in string theory. These models are better described in terms of a Minkowski 3-form field which couples linearly to the axion, in the Kaloper-Sorbo fashion. We highlight the differences between this simple effective theory and the structure actually obtained from string theory. We show that all the RR...

Mr
Pietro Longhi
(Uppsala University)

9/28/16, 4:35 PM

String & Mathematical Physics

New relations between wall crossing invariants, such as the BPS monodromy, and various limits of superconformal indices of 4d N=2 theories have been recently proposed. For theories of class S on their Coulomb branches, spectral networks provide a way to compute BPS monodromies directly, in a neighborhood of the superconformal point. Several new results on BPS monodromies can be obtained in...

Dr
Diego Regalado
(MPP Munich)

9/28/16, 4:55 PM

String & Mathematical Physics

I will describe a class of four dimensional field theories constructed by quotienting ordinary N=4 U(N) SYM by particular combinations of R-symmetry and SL(2,Z) automorphisms. These theories appear naturally on the worldvolume of D3 branes probing terminal singularities in F-theory, where they can be thought of as non-perturbative generalizations of the O3 plane. I will focus on cases...

Dr
Aswin Balasubramanian
(DESY and Univ of Hamburg)

9/28/16, 5:15 PM

String & Mathematical Physics

I'll talk about my work with J. Distler (to appear) in which we study a class of 3d N=4 superconformal field theories and their mass deformations. We perform this study by establishing a relation between the geometry of the vacuum moduli spaces of these theories and (a refined version of) the ``Theory of sheets" which is an important subject in Geometric Representation Theory. This realizes...

Nezhla Aghaei
(DESY)

9/28/16, 5:30 PM

String & Mathematical Physics

Mr
Orestis Loukas
(University of Bern)

9/29/16, 2:00 PM

String & Mathematical Physics

I will introduce the basic concepts of Large-Charge Perturbation Theory (LCPT) in d+1 space-time dimensions.
Given a Quantum Field Theory with a globally conserved charge Q, LCPT aims at providing analytic insight to sectors, which remain inaccessible via ordinary perturbative methods, but where Q is assumed to be large.
To this end, the scalar O(2) model with $\phi^N$ self-interaction will...

Mr
Wadim Wormsbecher
(Hu Berlin)

9/29/16, 2:15 PM

String & Mathematical Physics

We investigate the collinear behavior of tree level amplitudes in several theories using their CHY (Cachazo-He-Yuan) representation. We obtain the leading and subleading orders of the adjacent collinear limit and ask the question whether universality is present and how Einstein-Yang-Mills amplitudes emerge by checking specific identities due to Stieberger and Taylor.

Dr
Oliver Schlotterer
(AEI Potsdam)

9/29/16, 2:30 PM

String & Mathematical Physics

In this talk we derive the tree-level S-matrix of the effective theory of
Goldstone bosons known as the non-linear sigma model (NLSM) from
string theory. This novel connection relies on a recent realization of tree-level
open-superstring S-matrix predictions as a double copy of super-Yang--Mills theory
with Z-theory --- the collection of putative scalar effective field theories...

Martin Sprenger
(ETH Zürich)

9/29/16, 2:50 PM

String & Mathematical Physics

In this talk, I will describe the connection between the high-energy limit of the six-gluon scattering amplitude in N=4 super Yang-Mills theory and a certain class of single-valued polylogarithmic functions.
While the evaluation of the six-gluon amplitude to high loop orders in general kinematics is a very difficult problem, the amplitude in the multi-Regge regime is governed by a...

Dr
Florian Loebbert
(Humboldt University Berlin)

9/29/16, 3:10 PM

String & Mathematical Physics

Recently, Wilson loops in strongly coupled AdS/CFT were found to be invariant under a curious one-parameter family of deformations. In this talk we analyze the nonlocal symmetry underlying this observation. We show that it acts as a raising operator on the Yangian charges and generates the spectral parameter of the model. We also speculate about the possibility to extend this symmetry beyond...

Marco Meineri
(EPFL)

9/29/16, 3:30 PM

String & Mathematical Physics

Rényi entropies, and entanglement entropy in particular, are popular measures of entanglement in quantum theories. We present a holographic method for computing the response of Rényi entropies in conformal field theories to small shape deformations around a flat (or spherical) entangling surface. Our strategy is based on general properties of conformal field theories in the presence of...

Pedro Liendo
(DESY)

9/29/16, 4:05 PM

String & Mathematical Physics

Dr
Daniela Cadamuro
(Universität Göttingen)

9/29/16, 4:25 PM

String & Mathematical Physics

In the context of constructing interacting quantum field theories in the operator-algebraic approach, wedge-local fields play an important role. After the work of Lechner to construct factorizing scattering matrix models with scalar S-matrices without bound states, we recently extended this construction to the Z(N)-Ising model and the A_N-1 affine Toda field theories, namely models with a...

Dr
Lorenzo Bianchi
(Hamburg University)

9/29/16, 4:45 PM

String & Mathematical Physics

We consider possible discretizations for a gauge-fixed Green-Schwarz action of Type IIB superstring. We use them for measuring the action, from which we extract the cusp anomalous dimension of planar N=4 SYM as derived from AdS/CFT, as well as the mass of the two AdS excitations transverse to the relevant null cusp classical string solution. For both the observables, we find a good agreement...

Jacek Wosiek
(Jagellonian University)

9/29/16, 5:00 PM

String & Mathematical Physics

A positive representation for an arbitrary complex, gaussian weight is derived and used to construct a statistical formulation of gaussian path integrals directly in the Minkowski time. The positivity of Minkowski weights is achieved by doubling the number of real variables. The continuum limit of the new representation exists only if some of the additional couplings tend to infinity and are...