# Institut d'été XLVI

29 August 2016 to 2 September 2016
Paris, France
Europe/Paris timezone

## Titles and abstracts

Daniele Dorigoni

Title: Resurgence in eta-deformed Principal Chiral Models

Abstract: In this talk I study the SU(2) Principal Chiral Model (PCM) in the
presence of an integrable η-deformation.  By reducing the theory to
quantum mechanics I obtain the Whittaker-Hill equation whose ground
state energy I compute. I review some basic concept in resurgence
theory and, by studying the large order behaviour of perturbation
theory, I recover new non-perturbative effects called fractons,
responsible for the IR renormalons. I show that these fractons are
modified from the standard PCM due to the presence of this
η-deformation but they are still the constituents of uniton-like
solutions in a complexification of the deformed quantum field theory.

Title: Review of LHC searches for physics beyond the Standard Model

Abstract: I will review the state-of-the-art new physics searches at
the LHC, including the latest update based on up to 16 inverse
femtobarn at 13 TeV. I will also discuss the signification of these
result for model building beyond the Standard Model.

Hee Cheol Kim

Title: Monopoles and Vortices in 3d SUSY gauge theories

Abstract: In 3d gauge theories, monopole operators create and destroy vortices. The monopole operators generate an interesting algebra which naturally acts on vortex states. In this talk, I will show how to construct these 3d monopole operators in the 1d quantum mechanics describing the moduli space of vortices and also show that the quantum algebra generated by monopole operators can be obtained from localization computation.

João Penedones

Title: S-matrix bootstrap revisited

Abstract: Inspired by the recent success of the numerical approach to the conformal bootstrap, we revisit the S-matrix bootstrap program. We shall explain how to obtain analytic bounds on the interaction strength in 1+1 QFT. In higher dimensions, we propose a numerical algorithm that seems to converge to optimal bounds.

Leonardo Rastelli

Title: How to succeed at holographic correlators without really trying.''

Abstract: In this talk I will revisit the calculation of holographic correlation functions in IIB supergravity on AdS_5 × S^5 . Results for four-point functions simplify drastically when expressed in Mellin space. I will motivate the conjecture of a compact formula for four-point functions of one-half BPS singe-trace operators of arbitrary weight. These methods rely on general consistency conditions and eschew detailed knowledge of the supergravity effective action. [Based on work with Xinan Zhou, arXiv:1608:06624 & to appear.]

Rodolfo Russo

Title: CFT correlators at large c with(out) information loss

Abstract: According to the AdS/CFT duality, heavy CFT states whose conformal dimension scales with the central charge c correspond, on the gravity side, to non-trivial string backgrounds that are asymptotically AdS. I will focus on the AdS3/CFT2 case arising from the decoupling limit of a stack of D1 and D5-branes, where we have a precise dictionary between classes of heavy CFT states and dual geometries in the 1/8-BPS sector. I will discuss in some concrete examples when the large c CFT correlators with two heavy and two light operators are captured by a black hole geometry and when this description fails (thus avoiding any information loss).

Amit Sever

Title: Strings from Massive Higher Spins: The Asymptotic Uniqueness of the Veneziano Amplitude

AbstractWe consider weakly-coupled theories of massive higher-spin particles. This class of models includes, for instance, tree-level String Theory and Large-N Yang-Mills theory. The S-matrix in such theories is a meromorphic function obeying unitarity and crossing symmetry. We discuss the (unphysical) regime s,t ≫ 1, in which we expect the amplitude to be universal and exponentially large. We develop methods to study this regime and show that the amplitude necessarily coincides with the Veneziano amplitude there. In particular, this implies that the leading Regge trajectory, j(t), is asymptotically linear in Yang-Mills theory. Further, our analysis shows that any such theory of higher-spin particles has stringy excitations and infinitely many asymptotically parallel subleading trajectories. More generally, we argue that, under some assumptions, any theory with at least one higher-spin particle must have strings.

Alberto Zaffaroni

Title: AdS4 black holes and 3d gauge theories

Abstract: One of the great success of string theory is the microscopical explanation of the entropy of a class of asymptotically flat black holes.
Much less is known about asymptotically AdS  black holes in four dimensions or higher. In this talk I explain how to derive the entropy of a class of asymptotically AdS supersymmetric black holes
in four dimensions using holography. The counting of black hole micro-states is related to a counting of states in the dual 3d gauge theory which can be explicitly
performed using localization.

Michele del Zotto

Title: Exceptional Properties for Exceptional Instantons

Abstract: According to the recent classification of 6d (1, 0) theories within F-theory there are only 5 pure'' 6d gauge theories which have a superconformal UV completion. The corresponding gauge groups are SU(3), SO(8), F4, E6, E7, and E8. These exceptional models have BPS strings which are also instantons for the corresponding gauge groups. The ADHM construction, however, does not capture the corresponding worldsheets. For G simply-laced, we determine the 2d N = (0, 4) worldsheet theories of such BPS instanton strings by a simple geometric engineering argument. These are given by a twisted S2 compactification of the 4d N = 2 theories of type H2, D4, E6, E7 and E8 (and their higher rank generalizations), where the 6d instanton number is mapped to the rank of the corresponding 4d SCFT. This determines their anomaly polynomials and, via topological strings, establishes an interesting relation among the corresponding T2 × S2 partition functions and the Hilbert series for moduli spaces of G instantons. Such relations allows to bootstrap'' the corresponding elliptic genera by modularity. As an example of such procedure, the elliptic genera of the one-instanton strings are determined. As an aside, these results unveil a rather surprising relation with the Schur index of the corresponding 4d N = 2 models. Based on joint work with G. Lockhart.