EQuAL Seminar: Gabrielle Roberts

"Quantum Fluids in a Bose-Hubbard Circuit"

A central challenge of modern quantum science is understanding strongly correlated quantum matter. Inspired by Feynman, one way to approach the problem is to recreate the physics of interest in pristine analog quantum simulators. Microwave photons in superconducting circuits have proven to be a rich testbed for modeling many-body phenomena. In this talk, we use superconducting quantum circuits to construct and probe strongly interacting quantum fluids in a 1D Bose-Hubbard circuit. We deterministically prepare fluid eigenstates of our system using particle-by-particle assembly and adiabatic control of lattice site detuning. Site-resolved readout enables characterization of the multi-particle fluids and probe particle entanglement and correlations. The adiabatic state preparation technique is reversible; combining it with a manybody Ramsey experiment, we prepare cat states of quantum fluids, and then localize the information about energy differences of these highly entangled and delocalized states into one qubit for measurement. With this single qubit measurement, we then extract information about the manybody eigenstates, the associated excitation spectrum, and thermodynamic observables, a compelling example of how control and measurement overhead need not scale with system size.