Topological Maxwell Metal Bands in a Superconducting Qutrit

TL;DR

This paper experimentally demonstrates topological Maxwell metal bands in superconducting circuits, revealing Maxwell points, topological phase transitions, and measuring higher Chern numbers, advancing quantum simulation of topological phases.

Contribution

It is the first experimental realization of Maxwell metal bands in superconducting circuits, including the observation of Maxwell points and higher Chern numbers.

Findings

Observation of Maxwell points in superconducting circuits

Demonstration of topological phase transition

Measurement of higher Chern numbers

Abstract

We experimentally explore the topological Maxwell metal bands by mapping the momentum space of condensed-matter models to the tunable parameter space of superconducting quantum circuits. An exotic band structure that is effectively described by the spin-1 Maxwell equations is imaged. Three-fold degenerate points dubbed Maxwell points are observed in the Maxwell metal bands. Moreover, we engineer and observe the topological phase transition from the topological Maxwell metal to a trivial insulator, and report the first experiment to measure the Chern numbers that are higher than one.