12:00–1:00 pm
Please Join us:
Gabrielle Roberts’ PhD Thesis Defense
Friday, October 27 at 12:00 PM CDT
QUANTUM FLUIDS IN A BOSE-HUBBARD CIRCUIT
A central challenge of contemporary physics is understanding strongly correlated quantum matter at the microscopic level, with important applications in materials, medicine, and infrastructure. We approach this problem by recreating the physics of interest in pristine quantum simulators. Microwave photons in superconducting circuits have proven to be a rich testbed for modeling many-body phenomena. This platform boasts excellent single-particle and single-site control, site-resolved readout, long quantum state lifetimes compared to the timescale of dynamics, flexible geometries, and prospects for engineered cooling, opening up a variety of avenues to showcase new techniques for gaining physical intuition about manybody physics. In this thesis, 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.
Committee Members:
David Schuster (Co-Chair)
Jonathan Simon (Co-Chair)
David DeMille
Liang Jiang
Gabrielle will be a Research Scientist at Google Quantum AI.