12.04.2023 (Wednesday)

Lieb-Schultz-Mattis, t Hooft and Luttinger: anomalies in lattice systems

Triangular Seminar Meng Cheng (Yale)

at:
15:00 QMUL
room David Sizer Lecture Theatre
abstract:

In this talk I will discuss aspects of global symmetry and their t Hooft anomalies in lattice systems. I will discuss how anomalies are defined and probed using topological defects, which will be applied to both internal and lattice symmetries. The latter arise in systems satisfying Lieb-Schultz-Mattis-type theorems. Using the example of a spin-1/2 XXZ chain, I will also discuss how the continuum limit of a lattice model is properly described in terms of a low-energy theory with topological defects. In particular, I will show that t Hooft anomaly explains a curious size dependence of the ground state lattice momentum in the spin-1/2 XXZ chain.