Physics

Global symmetries in two dimensions are implemented by topological defect lines (TDLs). For continuous global symmetries, the TDLs are nothing but the Noether charges. However, there are TDLs that are not associated to any global symmetry, and can...

I will explore the generalization of the Feynman path integral in quantum field theory to complexified fields, and explain how it can be utilized to tackle the famous "sign problem". The sign problem prevents first principle studies of real-time...

The paradigmatic example of $AdS_4/CFT_3$ relates M-theory on $AdS_4 x S^7$ to the family of maximally supersymmetric 3d CFTs discovered by Aharony, Bergman, Jafferis, and Maldacena (ABJM). I will focus on the stress tensor four point function for...

In finite entropy systems such as black holes, real-time partition functions do not decay to zero at late times. It is a challenge to derive this non-decaying behavior starting from the path integral over the master fields of a large N theory. I...

It has been recently recognized that the same type of melonic large N structure governs SYK models and tensor models alike. Following Witten and Klebanov-Tarnopolsky, this has led to the introduction of new SYK-like tensor models, which reproduce...

Noether's theorem is textbook material in quantum field theory, but among experts it has been known for a while that there are quantum field theories with continuous global symmetries which possess no conserved current. In this talk I will give a...

Inspired by a recent computation of holographic entanglement entropy in flat space holography, we proposed a covariant prescription to compute holographic entanglement entropy and Poincare blocks (Global BMS blocks) in the context of three...

Interacting unitary conformal fixed points in five dimensions are mysterious objects which often do not have weakly coupled UV descriptions. Their conformal data such as operator spectrum and correlation functions appear more elusive to conventional...

Quantum field theories with a large number of fields offer a number of simplifications, and in some cases allow for computations at strong coupling. Two canonical examples are field theories where the fundamental fields are vectors, such as the O(N)...

I discuss the partition functions of supersymmetric gauge theories on Seifert manifolds. First we consider the case of 3d N=2 theories on a three-manifold $M_{g,p}$, a degree-p principal U(1) bundle over a smooth, genus-g Riemann surface. This...