Speaker: Matthew Neeley, University of California - Santa Barbara
Abstract: Quantum computers are typically thought of as being composed of qubits, or two-level quantum systems. However, one can also use qutrits (three-level systems) or general qudits (d-level systems) in quantum information processing, which can simplify certain computational tasks. Like many physical realizations of qubits, the superconducting phase qubit is a quantum system with multiple energy levels that is usually operated as a qubit by restricting it to the lowest two energy states. Here, we relax this restriction and instead use the higher levels to operate this device as a qudit up to d=5. We show how to manipulate and measure the qudit state, and then use it to emulate the dynamics of single spins with principal quantum number s=1/2, 1 and 3/2. In particular, we use this emulation to show the even (odd) parity of integer (half-integer) spins under 2pi rotation.