“Strings, CFT & Integrability”
Fall Semester 2017
Organised by: Niklas Beisert, Mahdi Godazgar, Christoph Keller and Blagoje Oblak
day
date
date
time
venue
venue
speaker
title
title
Tue
19.09.
11:30
HIT E41.1
Benoit Vicedo (University of Hertfordshire)
“Integrable field theories and dihedral affine Gaudin models”
abstract (click to view)
The quantisation of so called non-ultralocal classical integrable field theories is an important open problem in Mathematical Physics. I will explain how this problem can be reformulated mathematically within the framework of affine Gaudin models. I will also motivate this new perspective on non-ultralocality as a way of understanding the massive ODE/IM correspondence, a conjectural classical/quantum duality in integrable field theories. (click to hide)
Tue
03.10.
11:30
HIT E41.1
Sameer Murthy (King's College, London)
“Entanglement, Replicas, and Thetas”
Tue
03.10.
13:30
Johannes Noller (ETH ITS)
abstract (click to view)
In this talk I will give a whistle-stop tour of our current understanding of the fundamental building blocks of gravity in close analogy to the way in which we understand the other forces in nature. I will show to what extent we have already decoded nature's blueprint at this level, where recent progress has been made and how all this affects observable phenomena from the very large (e.g. the evolution of galaxies) to the very small (e.g. the discovery of new elementary particles). Along the way I will also highlight where some long-standing challenges to our current best theories of gravity exist and how recent theoretical progress may assist in resolving them. (click to hide)
Tue
10.10.
11:30
HIT E41.1
Linus Wulff (Masaryk University)
“Classifying integrable symmetric space strings”
abstract (click to view)
We show how the requirement of factorized scattering can be used to rule out integrability for strings in AdS backgrounds. This leads to a classification in the case of symmetric spaces. (click to hide)
Tue
17.10.
11:30
HIT E41.1
Charles Melby-Thompson (Julius-Maximilians-Universität Würzburg)
“Double Trace Defects in Holography”
abstract (click to view)
Perhaps the simplest RG flows in the AdS/CFT correspondence are those triggered by double trace deformations, which are realized holographically by a choice of boundary asymptotics for the fluctuations of a scalar field in the unitarity window. We consider the holographic realization of RG interfaces separating the two ends of this RG flow, which we call double trace interfaces.
In the limit of large central charge, we derive the spectrum of non-trivial interface operators, the 2-point function, and relations between the bulk and interface OPE coefficients. We show that our results match conformal perturbation theory in the regime where both methods are valid. We also compute the interface g-factor.
We further argue that within 3d higher spin gravity, our construction realizes the integrable RG defects in the W_{N,k} minimal models studied by Gaiotto. We reproduce the large-N limit of several of Gaiotto’s overlap coefficients and, computing the interface g-factor exactly in CFT, find that at large N it coincides with our holographic result. (click to hide)
In the limit of large central charge, we derive the spectrum of non-trivial interface operators, the 2-point function, and relations between the bulk and interface OPE coefficients. We show that our results match conformal perturbation theory in the regime where both methods are valid. We also compute the interface g-factor.
We further argue that within 3d higher spin gravity, our construction realizes the integrable RG defects in the W_{N,k} minimal models studied by Gaiotto. We reproduce the large-N limit of several of Gaiotto’s overlap coefficients and, computing the interface g-factor exactly in CFT, find that at large N it coincides with our holographic result. (click to hide)
Tue
24.10.
11:30
HIT E41.1
Andrea Campoleoni (ETH Zürich)
“Higher-spin BMS symmetries in four dimensions and soft theorems”
Tue
31.10.
11:30
HIT E41.1
Hagen Muenkler (ETH Zürich)
“Symmetries of smooth Wilson loops”
Tue
07.11.
11:30
HIT E41.1
Sergey Frolov (Trinity College, Dublin)
“Free field representation of the Zamolodchikov-Faddeev algebra and form factors of the SU(N) x SU(N) Principal Chiral Field model”
abstract (click to view)
A free field representation of the Zamolodchikov-Faddeev algebra of the SU(N) x SU(N) Principal Chiral Field model is constructed, and used to derive an integral representation for form factors of a multi-parameter family of exponential fields. (click to hide)
Tue
07.11.
14:00
HIT E41.1
Vasily Pestun (IHES)
“Non-simply laced q-deformed W-algebras from fractional instantons”
abstract (click to view)
I will discuss the construction of the generators of q-deformed W-algebra(g) for arbitrary simple Lie algebra g, including the non-simply laced cases, in terms of the geometry of the moduli spaces of fractional instantons and Coulomb branches of fractional quiver gauge theories. (click to hide)
Tue
14.11.
11:30
HIT E41.1
Jules Lamers (Chalmers University)
“Resurrecting the q-analogue of the Haldane–Shastry spin chain”
Tue
21.11.
Florian Loebbert (Humboldt University)
“Yangian Symmetry for Fishnet Feynman Graphs”
Tue
05.12.
11:30
HIT E41.1
Edoardo Vescovi (U. Sao Paulo)
“Two non-BPS Wilson loops: quark-antiquark potential in defect CFT and circular loop beyond the wavy approximation”
abstract (click to view)
I will describe interesting features of two observables measured by non-BPS Wilson loops.
In the first part I determine the potential energy of a quark-antiquark pair in a Higgsed variant of N=4 SYM with a codimension-1 defect [1708.04884] at weak coupling via gauge perturbation theory and at strong coupling in the dual D3-D5 brane system. In the latter regime, the relevant string free energy displays Gross-Ooguri transitions between a connected string surface and a phase where the string breaks into two disconnected surfaces.
In the second part I consider small deformations of the circular Wilson loop in N=4 SYM and of the dual minimal surface in hyperbolic space H_3. The formalism introduced by Kruczenski showed that the Wilson loop vev at strong coupling is invariant under certain deformations of the boundary contour. This symmetry was later found by Dekel to break down at weak coupling only at an unexpected high order in the deformation parameter. I report ongoing progress to understand this approximate symmetry in gauge theory. (click to hide)
In the first part I determine the potential energy of a quark-antiquark pair in a Higgsed variant of N=4 SYM with a codimension-1 defect [1708.04884] at weak coupling via gauge perturbation theory and at strong coupling in the dual D3-D5 brane system. In the latter regime, the relevant string free energy displays Gross-Ooguri transitions between a connected string surface and a phase where the string breaks into two disconnected surfaces.
In the second part I consider small deformations of the circular Wilson loop in N=4 SYM and of the dual minimal surface in hyperbolic space H_3. The formalism introduced by Kruczenski showed that the Wilson loop vev at strong coupling is invariant under certain deformations of the boundary contour. This symmetry was later found by Dekel to break down at weak coupling only at an unexpected high order in the deformation parameter. I report ongoing progress to understand this approximate symmetry in gauge theory. (click to hide)
Tue
12.12.
11:30
HIT E41.1
Joan Simon (University of Edinburgh)
“EPR=ER in LLM”
last modified: Wed, 6 Dec 2017, 14:27 CET