# “Strings, CFT & Integrability”

## First semester 2018-2019

Wednesday, 11:00, HIT E41.1

Organised by: Matthias Gaberdiel, Blagoje Oblak, Hagen Münkler

day
date
time
venue
speaker
title
Thu
16.08.
11:00
HIT E41.1
Kiryl Pakrouski (Princeton)
“Spectrum of O(4)^3 Majorana Tensor Model: SYK-like system without disorder”
Tue
25.09.
11:30
HIT E41.1
Agnese Bissi (Uppsala University)
“Analytic conformal boostrap and its applications”
Wed
03.10.
11:00
HIT E41.1
Piotr Tourkine (CERN)
“New twisted string theories”
abstract (click to view) Twistor strings have undergone a renewal of interest since the discovery of the Cachazo-He-Yuan formalism for scattering amplitudes in field theory in 2013. These formulae deeply challenge the way we think about scattering amplitudes in quantum field theory and are neatly explained by the so-called ambitwistor string, a cousin of the old twistor string. The existence of these remarkable formalisms, which I shall present to you during the talk, called for a connection to good old string theory. The answer to this question is now understood: it relies on counter-intuitive limits and crucially, the existence of a different quantization for string theory, which we called “twisted strings”. The first part of the talk will be concerned on making that connection to string theory clear. In the second part of the talk, I’ll report on recent results obtained with Eduardo Casali on the winding modes of these twisted strings. They give rise to new exotic target space theories, naively non unitary, but exhibiting features half way between string and field theory. In particular, they are T-duality symmetric. (click to hide)
Wed
10.10.
11:00
HIT E41.1
Rob Klabbers (Humboldt University)
“Holographic correlators finally cracked”
abstract (click to view) In this talk I will discuss recent advances in the computation of four-point functions of 1/2 BPS operators in N=4 SYM using AdS/CFT. These are the simplest dynamical correlation functions and their study goes back to the early days of AdS/CFT research. Not long ago the proposition of a closed formula in Mellin space for the strong-coupling limit of these four-point functions rekindled interest in them, as further results could disprove or corroborate the conjectured formula. I will discuss how one can compute the strong-coupling limit of these correlation functions using the supergravity action through the AdS/CFT correspondence. I will in particular explain how the algorithm was recently improved to allow for the computation of virtually any correlator of 1/2 BPS operators. Moreover, I will explain how to go from these coordinate space results to Mellin space and back. (click to hide)
Wed
17.10.
11:00
HIT E41.1
Pietro Longhi (ETH Zurich)
“BPS counting in five dimensions with lagrangian defects”
Wed
24.10.
11:00
HIT E41.1
Ruben Monten (CEA Saclay)
“Higher spin quantum gravity in de Sitter space”
Wed
31.10.
11:00
HIT E41.1
Roberto Tateo (INFN Turin)
“TTbar-deformed classical and quantum field theories”
abstract (click to view) Surprising links between the deformation of 2D quantum field theories induced by the composite $T \bar{T}$ operator, effective string models and the AdS/CFT correspondence, have recently emerged. I will discuss various classical and quantum aspects of this special irrelevant perturbation, including its geometrical interpretation at classical level. (click to hide)
Wed
07.11.
11:00
HIT E41.1
Ben Gripaios (University of Cambridge)
t.b.a.
Wed
14.11.
11:00
HIT E41.1
Enrico Brehm (AEI Golm)
t.b.a.
Tue
20.11.
11:30
HIT E41.1
Falk Hassler (University of Oviedo)
t.b.a.
Wed
21.11.
11:00
HIT E41.1
Daniel Medina Rincon (ETH Zurich)
t.b.a.
Wed
28.11.
11:00
HIT E41.1
Benjamin Basso (ENS Paris)
t.b.a.
Wed
05.12.
11:00
HIT E41.1
Fabian Ruehle (University of Oxford)
t.b.a.
Wed
12.12.
11:00
HIT E41.1
Du Pei (Aarhus University)
t.b.a.