Exact numerical and theoretical results beyond Fermi liquid theory

Edwin Huang 

Moore Postdoctoral Fellow 

University of Illinois at Urbana-Champaign

Landau's theory of Fermi liquids forms the basis for our understanding of normal metals and their ordering instabilities. Understanding and characterizing the behavior of strongly correlated quantum materials outside the Fermi liquid paradigm is one of the foremost problems in condensed matter physics. In this talk, I will first present numerically exact quantum Monte Carlo calculations of the Hubbard model, where we find large, linear-in-temperature resistivity indicating strange metallic transport and incompatibility with quasiparticle pictures. Then, I will discuss recent results obtained for the little-known Hatsugai-Kohmoto (HK) model, a minimal and exactly solvable model for Mott insulators. We find that the non-Fermi liquid normal state of the model exhibits a superconducting instability that gives rise to a distinctly non-BCS superconducting state. These results demonstrate the utility of simplified models in capturing exotic physics beyond Fermi liquid theory.

References:

1. EWH, R. Sheppard, B. Moritz T. P. Devereaux, Science 366, 987 (2019)

DOI: 10.1126/science.aau7063

2. P. W. Phillips, L. Yeo, EWH, Nature Physics 16, 1175 (2020)

DOI: 10.1038/s41567-020-0988-4