Emulating the Bose-Hubbard Model with Arrays of Superconducting Qubits
William D. Oliver
Massachusetts Institute of Technology
In this talk, we study the propagation, entanglement, and entropy of quantum information using 3x3 and 4x4 arrays of superconducting qubits that emulate the two-dimensional (2D) hard-core Bose-Hubbard model. The 2D arrays feature site-selective, simultaneous control and readout of all qubits. We highlight several recent experimental demonstrations using these arrays, including quantum random walks, Anderson and Wannier-Stark localization [1], and multi-excitation localization observed using out-of-time-ordered correlators (OTOCs) and Loschmidt echoes [2]. Finally, we present a means to generate superpositions of eigenstates of the hard-core Bose-Hubbard model, extracting correlation lengths and entanglement entropy across its many-body spectrum. We observe volume-law entanglement scaling for states at the center of the spectrum and a crossover to area-law scaling near its edges [3].
[1] npj Quantum Information 8, 35 (2022) | arXiv:2107.05035 (2021)
[2] Nature Physics 18, 172-178 (2022) | arXiv:2102.11751 (2021)