High-fidelity analog quantum simulation with superconducting qubits

Analog quantum simulation is a promising path for achieving beyond-classical simulation applications, particularly due to its faster entanglement growth than digital circuits. The higher classical simulation complexity in analog simulation is rooted in the simultaneous interaction between all qubits and the potential inclusion of non-computational states in the Hilbert space; however, these same aspects also make analog calibration a daunting task. We here report on recent progress toward a transmon-based high-fidelity analog quantum simulator. Specifically, we present a new analog calibration framework achieving significant reduction in eigenfrequency error compared to past works. We then demonstrate time-domain control of the analog quantum simulator via cross-entropy benchmarking, and leverage hybrid digital-analog circuits to study the equilibrium and non-equilibrium properties of the 2D XY model. Our work paves the way for analog quantum simulation to become a competitive avenue toward beyond-classical applications.