Using the Fluxonium Qubit for Quantum Simulation
Superconducting qubits are created by connecting Josephson junctions, which are non-linear, non-dissipative elements, to simple electrical circuits. Using this same toolbox of inductors, capacitors, and Josephson junctions, one is also able to generate different interactions between qubits. In this talk, I will discuss prospects for using the fluxonium qubit for quantum simulation. The fluxonium qubit is particularly suited to quantum simulation because its energy spectrum is strongly anharmonic and tunable with applied external flux. I will describe a gradiometric circuit based on the fluxonium qubit; this circuit is the smallest building block for realizing a z z-type interaction between fluxonium qubits. We find excellent agreement between the measured spectroscopy of the circuit and the theoretically-predicted level transitions. In addition, this circuit is engineered to be insensitive to global magnetic field noise and allows us to bound the local and global flux noise present in the circuit. I will conclude with a proposal for coupling fluxonium qubits in a 1-dimensional array. This array can be mapped to an Ising chain and exhibits multiple quantum phase
transitions, whose signatures can be observed experimentally.