Adiabatic Preparation of a Superfluid in a Bose-Hubbard Quantum Circuit

Strongly-correlated quantum materials can be studied synthetically using the flexible toolset of microwave photons and superconducting circuits in the circuit QED paradigm. We build a 1D Bose-Hubbard lattice for photons where capacitively coupled transmon qubits serve as lattice sites and the transmon anharmonicity mediates strong photon-photon collisions. Individual frequency control over each site enables explorations of adiabatic state preparation. We discuss our efforts to prepare a superfluid state, study the diabatic to adiabatic regime, and quantify the reversibility of the state preparation as a measure of adiabaticity. Our circuit design allows for single-site and multi-site readout, enabling us to study both state population densities and correlations. These efforts can shed light on the intricate interplay of interactions and entanglement in these many-body systems.