Condensed Matter Theory Seminar - Shankar Ganesh - “Two gauge stories in quantum matter — from hyperbolic band theory to monopoles in spin liquids”

Event time: 
Tuesday, January 2, 2024 - 1:00pm to 2:00pm
Sloane Physics Laboratory SPL, Room 51 See map
217 Prospect Street
New Haven, CT 06511
Shankar Ganesh - University of Alberta
Event description: 

Hyperbolic lattices are synthetic materials where particles hop on a discrete tessellation of the hyperbolic plane. Encouraged by recent circuit-QED realizations of tight-binding models on such lattices, the first part of my talk will propose a band theory of Bloch-like states on hyperbolic lattices by exploiting an intriguing connection with (topological) Yang-Mills theory on higher-genus Riemann surfaces.

The second (unrelated) part of my talk will discuss the threat of monopoles to the stability of a Dirac spin liquid, and their spectroscopic signatures, on various lattices. Along the way, I shall rely on instanton methods to construct monopole operators and paint them as ’t Hooft vertices — fermion-number-violating interactions that have their origin in instanton-bound zero modes of the Dirac operator.

Host: Meng Cheng