Transport Through Quantum Melts

TL;DR

This paper models electrical transport in quantum phase transitions, emphasizing the role of disorder-induced tunneling and activation at saddle points, aligning theoretical resistivity laws with experimental data.

Contribution

It introduces a detailed theoretical framework for transport through disordered quantum phases, focusing on saddle point junctions and their resistance behavior.

Findings

Resistivity laws match recent experimental observations.

Disorder creates a percolating network affecting transport.

Dissipation mechanisms at zero temperature are discussed.

Abstract

We discuss superconductor to insulator and quantum Hall transitions which are first order in the clean limit. Disorder creates a nearly percolating network of the minority phase. Electrical transport is dominated by tunneling or activation through the saddle point junctions, whose typical resistance is calculated as a function of magnetic field. In the Boltzmann regime, this approach yields resistivity laws which agree with recent experiments in both classes of systems. We discuss the origin of dissipation at zero temperature.