During the semester we have a high energy seminar and a lunch seminar. In addition to these two seminars we participate in a joint theoretical high energy theory seminar in Newe Shalom. The joint seminar takes place on Tuesdays from 10:30 until 13:30 and includes two talks and lunch. This seminar is attended by the high energy groups of all the Israeli institutions and usually attracts a crowd of roughly twenty participants.

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Title: An overview of the Swampland

Abstract:The Swampland program aims at distinguishingeffective theories which can be consistently completed into quantum gravity in the ultraviolet from those which cannot. The main objective of this talk is to present an introduction to the field. I will also present a brief overview of some recentwork which proposes and tests some Swampland constraints, specifically relating to scale separation in anti-deSitter spaces and to the presence of gravitational instanton corrections in supersymmetric theories.

D-instantons perturbation theory

Title: Boundary Conditions for Chiral Fermions

Abstract: Iʼll describe boundary conditions for fermions in d=1+1,

dimensions, using the framework of boundary conformal field theory. Iʼll

explain how boundary states are classified by a mod 2 index, related to

their SPT phase, describe how one can follow RG flows from one boundary

state to another, and give a novel perspective on the Z_8 classification

of d=2+1 SPT phases

Title:

Modularity of supersymmetric partition functions

Abstract:

In this talk, I will present a novel modular property of 4d N=1

supersymmetric partition functions of supersymmetric theories with R-symmetry. It is a generalization of the modular invariance of the supersymmetric partitionfunction of two-dimensional supersymmetric theories on a torus i.e. of the elliptic genus. It comes from requiring consistency of partitionfunctions under gluing and, among other things, can be used to rederive the supersymmetric Cardy formula for four-dimensional gaugetheories that has played a key role in computing the entropy of supersymmetric black holes.

Title: Deformations of JT Gravity and Matrix Models,

Abstract: I will explain how the relation between two-dimensional JT gravity and a matrix model — that is a

random ensemble of quantum systems rather than a specific quantum system — can be generalized

when one perturbs the action of JT gravity to a more generic case. Based on arXiv:2006.13414.

See also arXiv:2006.11317 by Maxfield and Turiaci.

Anybody who is not on the list of the Israel string joint seminar and would like to listen to this seminar send your email to cobi@tauex.tau.ac.il and you will receive the zoom link

Title: “Non-Symmetries and 2-Dimensional QCD” ?Abstract :

We will review the subject of “non-symmetries’’ or “defect symmetries.” We will argue that massless two dimensional QCD admits exponentially many such symmetries and we use them to prove deconfinement as well as to compute exactly the tension of thestring in the small mass limit.

Title: Partition functions of the tensionless string

Abstract: I discuss string theory on AdS3xS3xT4 in the tensionless limit,with one unit of NS-NS flux. This theory is conjectured to be dual to the symmetric product orbifold CFT. I show how to compute the full string partition function on various locally AdS3 backgrounds, such as thermal AdS3, the BTZ black and conical defects,and find that it is independent of the actual background, but only depends on the boundary geometry. Consequently, reproducing the boundary partition function does not require a sum over bulk geometries,but rather agrees with the string partition function on any bulk geometry with the appropriate boundary. I argue that the same mechanism shows the factorization of the bulk partition function when geometries with disconnected boundaries are considered.

Title:

Merging Swampland Conjectures using strings and membranes

Abstract:

In this talk I will discuss new relations that appear among the Swampland Conjectures when analysing the properties of low codimension BPS objects, in particular strings and membranes in N=1 4D EFTs. I will review the state of the art of the Swamplandprogram and revisit the most important conjectures, namely the Weak Gravity Conjecture (WGC) and the Swampland Distance Conjecture (SDC). Then I will describe how to apply the WGC to low codimension BPS objects by interpreting the 4d backreaction of these objectsas a classical RG flow of their couplings. Constraints on the UV charges and tensions get then translated to constraints on the axionic kinetic terms and scalar potential of the EFT, which uncovers new relations among the Swampland Conjectures. In particular,we show that the WGC for strings implies the SDC, by using that infinite distance limits can be realised as RG flow endpoints of fundamental axionic strings. Similarly, WGC-saturating membranes generate a scalar potential satisfying the de Sitter Conjecture.