Tunable Quantum Criticality and Super-ballistic Transport in a `Charge' Kondo Circuit

TL;DR

This study uses a quantum circuit to simulate the three-channel Kondo model, revealing universal critical behaviors, multiple crossovers, and an unexpected conductance violation, advancing understanding of quantum criticality in strongly-correlated systems.

Contribution

It introduces a charge pseudospin Kondo circuit as a quantum simulator, enabling detailed exploration of quantum criticality and transport phenomena.

Findings

Universal scalings toward low-temperature fixed points

Multiple crossovers from quantum criticality

Violation of maximum conductance for ballistic electrons

Abstract

Quantum phase transitions are ubiquitous in many exotic behaviors of strongly-correlated materials. However the microscopic complexity impedes their quantitative understanding. Here, we observe thoroughly and comprehend the rich strongly-correlated physics in two profoundly dissimilar regimes of quantum criticality. With a circuit implementing a quantum simulator for the three-channel Kondo model, we reveal the universal scalings toward different low-temperature fixed points and along the multiple crossovers from quantum criticality. Notably, an unanticipated violation of the maximum conductance for ballistic free electrons is uncovered. The present charge pseudospin implementation of a Kondo impurity opens access to a broad variety of strongly-correlated phenomena.