Topological Maxwell Metal Bands in a Superconducting Qutrit

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. Threefold 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.

Non-Hermitian topological Anderson insulators

“…Such topological phases induced by the combination of non-Hermiticity and disorders are dubbed non-Hermitian topological Anderson insulators. We also find that the system has unique non-monotonous localization behaviour and the topological transition is accompanied by an Anderson transition.Topological states of matter have been widely explored in condensed-matter materials [1-5] and various engineered systems, which include ultracold atoms [6-8], photonic lattices [9, 10], mechanic systems [11], classic electronic circuits [12][13][14][15], and superconducting circuits [16][17][18][19][20]. One hallmark of topological insulators is the robustness of nontrivial boundary states against certain types of weak disorders, since the topological band gap (topological invariants) preserves under these perturbations [1][2][3].…”

Experimental Measurement of the Quantum Metric Tensor and Related Topological Phase Transition with a Superconducting Qubit

“…Experimental system.-We realize a highly tunable twolevel Hamiltonian with superconducting quantum circuits and measure the quantum metric using the two different methods. The circuits consist of a superconducting transmon qubit embedded in a three-dimensional aluminium (Al) cavity [19,20,[38][39][40][41]. The transmon qubit is composed of an Al single Josephson junction and two pads (250 µm × 500 µm) fabricated on a 500 µm thick silicon substrate.…”

“…The whole sample package is cooled in a dilution refrigerator to a base temperature of 10 mK. The experimental setups for the qubit control and measurement are well established [19,20,[38][39][40][41]. The coupled transmon qubit and cavity exhibit anharmonic multiple energy levels.…”

Simulating bosonic Chern insulators in one-dimensional optical superlattices

“…Recently, the exploration of topological phases has became an important research area in condensed matter physics [1][2][3][4][5] and various artificial systems, such as topological photonic and mechanic systems [6][7][8] and superconducting circuits [9][10][11][12]. In particular, ultracold atoms in optical lattices provide a powerful platform for quantum simulation of many-body physics and topological states of matter [13][14][15][16][17][18][19][20][21][22].…”