Quantum Theory Seminar - Akshat Pandey (Stanford University)

Title: What does a 2d infinite-randomness fixed point look like?

Abstract: The theorist often hopes that low-energy observables in critical theories with quenched disorder are characterised by their disorder-averaged counterparts (or perhaps by a small number of moments of the distribution). There are models which represent an opposite extreme, however, as they flow under the appropriate RG to “infinite-randomness” fixed points, characterised by distributions of observables that grow unboundedly broad with RG flow. These fixed points are well studied in one-dimensional models, but in two dimensions the RG generates random geometrical structure in the interaction graph which has not hitherto been analysed. The eventual fixed point lives in the space of joint distributions of geometries and couplings on those geometries. I will talk about what these notions mean in the 2d critical random transverse-field Ising model, and about the progress we have made in understanding the character of its flow to infinite randomness.

Faculty Hosts: Eun-Ah Kim, Chao-Ming Jian, and Debanjan Chowdhury