Author: Alessandro Sfondrini

On January 14 we will have a seminar by

Marc Henneaux (ULB & Collège de France)

Title: Asymptotic symmetries of electromagnetism and gravity: a Hamiltonian study

Abstract: The asymptotic symmetries of gravity and electromagnetism are remarkably rich.    The talk will explain the asymptotic structure of these theories in the asymptotically flat case by making central use of the Hamiltonian formalism.  In particular, how the relevant infinite-dimensional asymptotic symmetry groups emerge at spatial infinity will be discussed. Extensions to supergravity will be briefly touched upon.

Meeting information:
14th of January at 14:30 Italian Time
Zoom Meeting https://zoom.us/j/19843543

Slides are available at
https://pandora.infn.it/public/c8b1b7

You can watch the recording at
https://pandora.infn.it/public/06173b

On June 25 we will have a seminar by

Charlotte Kristjansen (Niels Bohr Institute)

Title: News on domain walls and integrability in N=4 SYM.

Abstract:
Domain walls in N=4 SYM theory separating regions with different vevs for the scalar fields allow us to study versions of AdS/CFT where supersymmetry is either partially or completely broken and where boundary integrability might or might not be present. We review the present status of this line of research paying particular attention to novel results on integrability beyond the scalar sector, at higher loops and for the non-supersymmetric D3-D7 probe brane set-up.

Meeting information:
25th of June at 14:30 Italian Time
Zoom Meeting https://zoom.us/j/198435430

Slides are available at
https://pandora.infn.it/public/9e97f9

You can watch the recording at
https://pandora.infn.it/public/cdc69a

On June 11 we will have a seminar by

Niels Obers (NORDITA)

Title: Non-relativistic gravity and strings

Abstract: I will start by motivating the recent interest in non-relativistic gravity and strings. These build on recent advances and generalizations of Newton-Cartan geometry, originally introduced by Cartan to geometrize Newtonian gravity. I will then present an action principle for non-relativistic gravity and its coupling to matter, including its Newtonian limit. This requires a new notion of NC geometry, which  naturally arises in a covariant 1/c expansion of general relativity, with c being the speed of light. The corresponding non-relativistic truncation of general relativity goes beyond Newtonian gravity and is able to correctly describe gravitational time dilation. Finally, I will discuss how non-relativistic geometry appears in connection to non-relativistic strings and limits of the AdS/CFT correspondence. 

Meeting information:
11th of June at 14:30 Italian Time
Zoom Meeting https://zoom.us/j/198435430

Slides are available at
https://pandora.infn.it/public/bd2da0

You can watch the recording at
https://pandora.infn.it/public/d05d44

On May 28 we will have a seminar by

Stephen Wolfram (Wolfram Research)

Title: A Surprisingly Promising Approach to the Fundamental Theory of Physics

Abstract:
What might an ultimate rule for physics—below space, time, particles, etc.—be like?  I had an idea about this 30 years ago, wrote about in 2002, and finally last fall decided to investigate it again … and to my great surprise realized that it actually looks as if it can work.  It has no intrinsic notion of space or time, but just consists in repeatedly (like 10^400 times) applying a very simple rule to abstract collections of elements and relations which can be thought of as forming a hypergraph.  With various assumptions the large-scale limit behaves like continuum space, shows Lorentz invariance, and reproduces the Einstein equations (including energy-momentum).  Different rewritings of the hypergraph define a multiway system, whose large-scale limit reproduces quantum mechanics, and in particular the path integral.  In the framework, general relativity and quantum mechanics are essentially the same theory, but applied to the spacetime causal graph as opposed to the multiway causal graph.  I’ll talk about the structure of the theory, some of its potential predictions, and (insofar as I understand them) its apparently close connections with popular recent mathematical physics approaches.

Meeting information:
28th of May at 18:30 Italian Time
Zoom Meeting https://zoom.us/j/198435430

You can watch the recording at
https://pandora.infn.it/public/28abf5

On April 30 we will have a seminar by

Juan Maldacena (IAS Princeton)

Title: The entropy of Hawking radiation and the information paradox

Abstract:
We will review recent progress on the black hole information paradox.
We start by reviewing some aspects of black hole thermodynamics.
Then we will introduce the formula for fine grained entropy of black holes. We apply it various examples. We then discuss how this formula computes the entropy of evaporating black holes as well as the entropy of Hawking radiation.

Meeting information:
30th of April at 16:30 Italian Time
Zoom Meeting https://zoom.us/j/198435430

Slides are available at
https://pandora.infn.it/public/2965e9

You can watch the recording at
https://pandora.infn.it/public/936a73

On April 16 we will have a seminar by

David Tong (Cambridge U.)

Title: A New 5d Non-Supersymmetric Fixed Point?

Abstract: The question mark is important.

Meeting information:
16th of April at 14:30 Italian Time
Zoom Meeting https://zoom.us/j/198435430

Slides are available at
https://pandora.infn.it/public/e46e51

You can watch the recording at
https://pandora.infn.it/public/615f1a

On April 2 we will have a seminar by

Noppadol Mekareeya (INFN Milano Bicocca & Chulangokorn U. Bangkok)

Title: 3d S-fold SCFTs

Abstract:
A local SL(2,Z) transformation on the Type IIB brane configuration gives rise to an interesting class of 3d superconformal field theories, known as the S-fold SCFTs. One of the interesting features of such a theory is that, in general, it does not admit a conventional Lagrangian description. Nevertheless, it can be described by a quiver diagram with a link being a superconformal field theory, known as the T(U(N)) theory. In this talk, we discuss various interesting properties of the S-fold theories, including supersymmetry enhancement in the infrared as well as several interesting dualities.

Meeting information:
2nd of April at 14:30
Zoom Meeting https://zoom.us/j/198435430

Slides are available at
https://pandora.infn.it/public/3c8cc4

You can watch the recording at
https://pandora.infn.it/public/1929ad

On March 26 we will have a seminar by

Massimo Taronna (Napoli U.)

Title: Bootstrapping (A)dS exchanges

Abstract:
Gravitational observables are inherently holographic in nature. When the asymptotic boundary of space time admits a canonical definition of time this allows to use standard principles of Quantum Mechanics to describe such observables. On the other hand the situation is not clear otherwise. This is the case in dS space where the boundary is space-like. Nonetheless bulk causality must be imprinted at the boundary in some way. In this talk I will discuss how to bootstrap tree level amplitudes both in AdS and dS. I will fix from first principles the form of such holographic observables discussing their singularities. In AdS I will also discuss how the knowledge of exchange amplitudes alone allows to derive non-perturbative constraints on CFT correlators writing down extremal functionals for the CFT bootstrap in arbitrary dimensions

Meeting information:
26th of March at 14:30
Zoom Meeting https://zoom.us/j/198435430

Slides are available at
https://pandora.infn.it/public/377a24

You can watch the recording at
https://pandora.infn.it/public/69ae67