Month: May 2020

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 18 we will have a seminar by

Luis Fernando Alday (Oxford)

Title: 6d (2,0) correlators and quantum M-theory

Abstract:
We study holographic correlators in maximally super-symmetric conformal field theories. This includes the 6d (2,0) theory, where our computation is dual to graviton scattering in weakly coupled M-theory on AdS₇ × S⁴. Although the theory is non-Lagrangian, analytic bootstrap techniques allow us to make computations to one loop order. The flat space limit of our results exactly reproduces the 11d M-theory S-matrix in flat space.

Meeting information:
18th of June at 14:30 Italian Time
Zoom Meeting https://zoom.us/j/198435430

Slides are available at
https://pandora.infn.it/public/aabe3f

You can watch the recording at
https://pandora.infn.it/public/6cb0c1

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 June 4 we will have a seminar by

Nathan Seiberg (IAS Princeton)

Title: Continuum Quantum Field Theories for Fractons

Abstract: Starting with a lattice system at short distances, its long-distance behavior is captured by a continuum Quantum Field Theory (QFT). This description is universal, i.e. it is independent of most of the details of the microscopic system. Surprisingly, certain recently discovered lattice systems, and in particular models of fractons, seem to violate this general dogma. Motivated by this apparent contradiction, we will present exotic continuum QFTs that describe these systems. This talk will have a different emphasis than previous talks with the same title and abstract.

Meeting information:
4th of June at 14:30 Italian Time
Zoom Meeting https://zoom.us/j/198435430

Slides are available at
https://pandora.infn.it/public/c15d10

You can watch the recording at
https://pandora.infn.it/public/7e4c79

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