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.

# Events Archive

## High Energy Theory Seminar

### HET Seminar | Alexei Kitaev, Caltech | “Topological Quantum Phases” | Bloomberg Lecture Hall

### Physics Group Meeting | Sridip Pal, IAS | "Towards optimal asymptotic spectral gap in 2D unitary GFT" | Bloomberg Hall Physics Library

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].

### HET Seminar - Radu Roiban - Pennsylvania State University

### HET Seminar | Edgar Shaghoulian, Cornell | "Integrable deformations in quantum mechanics, T-Tbar, and SYK" | Jadwin A06

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.

### HET Seminar | Theo Johnson-Freyd, Perimeter Institute | “TMF and SQFT” | Bloomberg Lecture Hall

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 "...

### High Energy Theory | Joao Penedones, EPFL | "S-matrix Bootstrap for Effective Field Theories"

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.

### Physics Group Meeting | "Title to be announced." | Bloomberg Hall Physics Library

### HET Seminar | Callum Jones, U of Michigan | "Born-Infeld Electrodynamics at One-Loop” | Jadwin A06

The Born-Infeld model is an effective field theory of central importance describing the low-energy dynamics of massless gauge bosons on the world-volume of D-branes. Though it is in many ways an exceptional model of nonlinear electrodynamics, several aspects of the physics of the Born-Infeld model remain mysterious.

### High Energy Theory | Jacobus Verbaarschot, Stony Brook | "Chaotic and Thermodynamic Properties of two Coupled Sachdev-Ye-Kitaev Models" | PCTS Seminar Room 407

The SYK Model was originally introduced as a random matrix model for the nuclear interaction that also describes the exponential rise of the spectral density known as the Bethe formula.

### Physics Group Meeting | Nafiz Ishtiaque, IAS | “Topological Holography” | Bloomberg Hall Physics Library

We consider supersymmetric twist and omega deformation of a type IIB brane setup involving N D3 and K D5 branes. In the large N limit, this leads to a holographic duality between two topological/holomorphic theories. We compute certain operator algebras from both sides of this topological holographic duality and find the result consistent with...

### HET Seminar | Tom Hartman, Cornell University | "Dynamical Constraints on RG Flows and Cosmology” | Bloomberg Lecture Hall

I will discuss time-dependent probes of the renormalization group, and derive new constraints that govern the spread of local operators in holographic theories. The same methods lead to sum rules for inflationary correlators, relating observables, like the speed of sound during inflation, to properties of the UV theory.

### Physics Group Meeting at IAS | Robert Penna, IAS | “The Geroch Group” | Bloomberg Hall Physics Library

We review some infinite dimensional symmetries that appear indimensionally reduced classical general relativity.

### Physics Group Meeting at IAS | Robert Penna, IAS | “The Geroch Group” | Bloomberg Hall Physics Library

We review some infinite dimensional symmetries that appear indimensionally reduced classical general relativity.

### HET Seminar | Bruno Balthazar, Harvard | "ZZ Instantons and the Non-Perturbative Dual of c=1 String Theory" | Jadwin A07

### High Energy Theory | Sabrina Gonzalez Pasterski - Princeton | "4D Scattering as 2D Correlators"

The asymptotic symmetry algebra of asymptotically flat spacetimes implies an infinity of conserved charges for 4D scattering which can be neatly recast as 2D conformal Ward identities.

### Physics Group Meeting at IAS | Baurzhan Mukhametzhanov, IAS | “Matrix Models and Minimal Liouville Gravity” | Bloomberg Lecture Hall

I will review some old ideas about the duality between matrix models and Liouville theory coupled to a (p,q) minimal model. In this approach t'Hooft diagrams of the matrix model are thought of as a discretization of a 2d surface. Fine-tuning of the coupling constant leads to divergence of the perturbative expansion.

### HET Seminar | Geoff Penington | Stanford University | “Entanglement Wedge Reconstruction and the Information Paradox” | Bloomberg Lecture Hall

When absorbing boundary conditions are used to evaporate a black hole in AdS/CFT, we show that there is a phase transition in the location of the quantum Ryu-Takayanagi surface, at precisely the Page time. The new RT surface lies slightly inside the event horizon, at an infalling time approximately one scrambling time in the past.

### High Energy Theory - "dS thermodynamics from bulk and horizon characters" Zimo Sun - Columbia

In this talk, I will discuss the idea that the exact one-loop free energy of the static patch of D-dimensional de Sitter space can be computed as a simple integral transform of an SO(1;D) bulk character corrected by an SO(1; D-2) edge character, for fields of arbitrary mass and spin. The bulk character captures the particle content of the...

### Physics Group Meeting @ IAS | Daniel Kapec, IAS | “Black Hole Images and the Photon Ring” | Bloomberg Hall Physics Library

The EHT Collaboration has recently published images of the supermassive black hole in M87. The images are dominated by a bright ring-like structure with an angular brightness asymmetry. While the diameter of this ring is resolved by the EHT, its thickness and detailed substructure are not.

### HET Seminar | Andrea Dei, ETH Zurich | "Three-point functions in AdS3/CFT2 holography." | Jadwin A06

String theory on AdS3xS3xT4 with one unit of NSNS flux has been recently argued to be dual to the symmetric product orbifold of T^4. The duality has been extended to the case of generic NSNS background flux. I will consider the bosonic version of this duality and show how to match null-vector constraints on three-point functions.