Events Archive

IAS HET Seminar | Giulio Salvatori, Member, School of Natural Sciences, IAS| “Scattering Amplitudes, Positive Geometries and Surfaces” | Wolfensohn Hall (behind Bloomberg Hall) & on Zoom
Fri, Mar 11, 2022, 1:45 pm1:45 pm

In recent years we have witnessed the emergence of a novel description for the physics of scattering amplitudes at the heart of which are mathematical structures called Positive Geometries, which loosely speaking are generalizations of polytopes having the crucial feature of encoding in their boundaries the singularity structure of…

HET Seminar | Beatrix Muhlmann, McGill University | “The semiclassical gravitational path integral and random matrices” | Via Zoom
Mon, Feb 21, 2022, 2:30 pm2:30 pm

According to Gibbons and Hawking the entropy of a dS universe is encoded in the Euclidean gravitational path integral over compact manifolds with dominant sphere saddle. In this talk I will report on recent work in which we explicitly calculate this gravitational path integral in two spacetime dimensions. Whereas the Euclidean two-dimensional…

HET Seminar |Justin Kaidi , Stony Brook University | “Kramers-Wannier-like duality defects in (3+1)d gauge theories” | Via Zoom
Fri, Feb 18, 2022, 1:45 pm1:45 pm

I will introduce a class of non-invertible topological defects in (3+1)d gauge theories whose fusion rules are the higher-dimensional analogs of those of the Kramers-Wannier defect in the (1+1)d critical Ising model. As in the lower-dimensional case, the presence of such non-invertible defects implies self-duality under a particular gauging of…

HET Seminar | Sabrina Gonzalez Pasterski, Princeton University | “The Celestial Almanac” | PCTS (Room 407) & Zoom
Mon, Feb 14, 2022, 2:30 pm2:30 pm

We start by revisiting the task of constructing a holographic dual to quantum gravity in asymptotically flat spacetimes. Upon recasting the S-matrix in terms of data at the conformal boundary, we see that the two standard approaches amount to slicing up the bulk and boundary in different ways.

The Celestial Hologram organizes…

IAS HET Seminar | Igor Klebanov, Princeton University; Distinguished Visiting Professor, School of Natural Sciences, IAS | "O(N), Sp(2M), and OSp(1|2M) Models" | Wolfensohn Hall (behind Bloomberg Hall) & on Zoom
Fri, Feb 11, 2022, 1:45 pm1:45 pm


The upper critical dimension of the O(N) vector model is well-known to be 4. In dimension 4-epsilon it is described by the Wilson-Fisher IR fixed point of the O(N) invariant scalar field theory with a small positive quartic coupling. Above 4 dimensions, this theory is non-renormalizable, but in 4+epsilon dimensions it…

IAS HET Seminar | Kevin Costello, Perimeter Institute | “Scattering Amplitudes in Gauge Theory as Chiral Algebra Correlators” | Wolfensohn Hall (behind Bloomberg Hall) & on Zoom
Mon, Feb 7, 2022, 2:30 pm2:30 pm

I will report on my recent work with Natalie Paquette, where we derive expressions for form factors and scattering amplitudes of gauge theory as correlators of a chiral algebra.  The chiral algebra is closely related to algebras appearing in the celestial holography program.



IAS HET Seminar | Shai Chester, Weizmann Institute of Science | "Bootstrapping N = 4 super-Yang-Mills on the conformal manifold" | Wolfensohn Hall (behind Bloomberg Hall) & on Zoom
Mon, Nov 15, 2021, 2:30 pm2:30 pm

Abstract:  We study the = 4 SYM stress tensor multiplet 4-point function for any value of the complexified coupling tau, and in principle any gauge group (we focus on SU(2) and SU(3) for simplicity). By combining non-perturbative constraints from the numerical bootstrap with two exact constraints from supersymmetric localization, we…

IAS HET Seminar | Ahsan Z Khan, Member, School of Natural Sciences, IAS | "TBA" | Wolfensohn Hall (behind Bloomberg Hall) & on Zoom
Fri, Nov 12, 2021, 1:45 pm1:45 pm
The Universe from a single Particle - Michael Freedman - Microsoft Q
Mon, Nov 1, 2021, 4:30 pm4:30 pm

I will explore a toy model for our universe in which spontaneous symmetry breaking – acting on the level of operators (not states) - can produce the interacting physics we see about us from the simpler, single particle, quantum mechanics we study as undergraduates. Based on joint work with Modj Shokrian Zini, see arXiv:2011.05917 and arXiv:2108…

IAS HET Seminar | Venkatesa Chandrasekaran, Member, School of Natural Sciences, IAS | "The Area Operator in Gravity and Holography" | Wolfensohn Hall (behind Bloomberg Hall) & on Zoom
Fri, Oct 29, 2021, 1:45 pm1:45 pm

Abstract:  The area operator plays a central role in our understanding of holography and black hole thermodynamics. In this talk I will discuss a formulation of the area operator at the level of classical gravity, the “kink transform”, which defines a notion of a half-sided boost of gravitational initial data. I will show that it satisfies the…

Special IAS HET Seminar | Nima Arkani-Hamed, Professor, School of Natural Sciences, IAS | "Spacetime and Quantum Mechanics; Particles and "Strings"; Polytopes, Binary Geometries and Quiver Categories" | Wolfensohn Hall (behind Bloomberg Hall) & on Zoom
Tue, Oct 26, 2021, 1:30 pm1:30 pm

Abstract: The past decade has seen the emergence of surprising new connections between the real-world physics of elementary particle scattering processes, and simple new mathematical structures in combinatorics, algebra and geometry. These ideas provide, in a number of examples, a different starting point for conceptualizing…

IAS HET Seminar | Michael Levin, University of Chicago | "Lattice Edge Theories for Topological Phases of Matter" | Wolfensohn Hall (behind Bloomberg Hall) & on Zoom
Mon, Oct 25, 2021, 2:30 pm2:30 pm

Abstract: Edge excitations of (2+1)D topological phases are usually described using continuum field theories. But the boundaries of some (2+1)D topological phases can also be described using lattice-like edge theories that have a finite dimensional Hilbert space for a finite size boundary. I will discuss several examples of…

IAS HET Seminar | Nathan Haouzi, Member, School of Natural Sciences, IAS | "Old and New Physics Prospects for q-Virasoro" | Wolfensohn Hall & on Zoom
Fri, Oct 22, 2021, 1:45 pm1:45 pm

This seminar will be presented in-person in Wolfensohn Hall at the IAS and on Zoom.

For contact-tracing purposes all off-campus attendees must register for this seminar: 

All in-person attendees…

HET Seminar | Alexei Kitaev, Caltech | “Topological Quantum Phases” | Bloomberg Lecture Hall
Fri, Dec 13, 2019, 1:45 pm1:45 pm

 I will discuss topological classification of gapped many-body Hamiltonians and their ground states in dimension d. In general, the problem is too hard as it includes diverse phenomena such as degenerate ground states on the torus, anyons, and fractons. There is, however, hope to fully understand short-range entangled, or "invertible" systems,…

Physics Group Meeting | Sridip Pal, IAS | "Towards optimal asymptotic spectral gap in 2D unitary GFT" | Bloomberg Hall Physics Library
Wed, Dec 11, 2019, 1:45 pm1:45 pm

We will prove a conjecture [1] on upper bound of asymptotic gap in dimension in unitary compact 2D CFT, proving it to be 1 using a "extremal" function [2]. The notion of asymptotic gap can be generalized to (h, \bar{h}) plane [3]. We will discuss how the extremal function used in [2] can be put into a bigger (natural) framework of an extremal…

HET Seminar - Radu Roiban - Pennsylvania State University
Mon, Nov 25, 2019, 2:30 pm2:30 pm
A free lecture open to the public.
HET Seminar | Edgar Shaghoulian, Cornell | "Integrable deformations in quantum mechanics, T-Tbar, and SYK" | Jadwin A06
Wed, Nov 20, 2019, 4:00 pm4:00 pm

The Wilsonian paradigm suggests universality of quantum field theory in the infrared. Interestingly, it also suggests universality of quantum mechanics (d=1 quantum field theory) in the ultraviolet. This suggests a study of the landscape of the infrared and the robustness of the ultraviolet. I will introduce and…

A free lecture open to the public.
HET Seminar | Theo Johnson-Freyd, Perimeter Institute | “TMF and SQFT” | Bloomberg Lecture Hall
Mon, Nov 18, 2019, 2:30 pm2:30 pm

I will describe my work, all joint with D. Gaiotto and some also joint with E. Witten, to understand the homotopy type of the space of (1+1)d N=(0,1) SQFTs --- what a condensed matter theorist would call "phases" of SQFTs. Our motivating hypothesis (due in large part to Stolz and Teichner) is that this space models the spectrum called …

A free lecture open to the public.
High Energy Theory | Joao Penedones, EPFL | "S-matrix Bootstrap for Effective Field Theories"
Mon, Nov 11, 2019, 2:30 pm2:30 pm

I will explain how the S-matrix Bootstrap for massless particles can be used to constrain the space of Effective Field Theories (EFT). In particular, I will discuss the S-matrix bootstrap for massless particles in unitary, relativistic two dimensional quantum field theories. In the context of flux tube physics, this…

A free lecture open to the public.
Physics Group Meeting | "Title to be announced." | Bloomberg Hall Physics Library
Mon, Nov 11, 2019, 1:45 pm1:45 pm