Novel Transport Phenomena in Quantum Matter

Abstract

This dissertation delves into the exploration of novel transport phenomena in quantum matter, with a particular emphasis on the strange metal problem and the thermal Hall effect, both of which have been observed in cuprate high-temperature superconductors. Regarding the strange metal problem, we begin by investigating a series of lattice models constructed from the Sachdev-Ye-Kitaev (SYK) models, which provide a robust mechanism for the strange metal phenomenology. Furthermore, we apply insights from the SYK model to the critical Fermi surface problem to construct a strange metal with a well-defined Fermi surface. The research ultimately leads to a controlled large $N$ theory that explains the behavior of the strange metal in a comprehensive manner. In regards to the thermal Hall effect, this dissertation explores various potential heat carriers and heat conduction mechanisms. Firstly, we investigate the scenario where the Hall effect arises due to the Berry curvature of emergent excitations. Secondly, we consider situations in which thermal Hall effect is produced by phonons through the skew-scattering mechanism or the side-jump mechanism.