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.
@article{arxiv.1709.05765,
title = {Topological Maxwell Metal Bands in a Superconducting Qutrit},
author = {Xinsheng Tan and Dan-Wei Zhang and Qiang Liu and Guangming Xue and Hai-Feng Yu and Yan-Qing Zhu and Hui Yan and Shi-Liang Zhu and Yang Yu},
journal= {arXiv preprint arXiv:1709.05765},
year = {2018}
}