Southwest Quantum Information and Technology

Optimizing control parameters for three-qubit gates

Presenting Author: Karl Mayer, National Institute of Standards and Technology & University of Colorado Boulder

Many problems in quantum control deal with performing a desired unitary transformation in a minimal amount of time, or utilizing a minimal number of resources. Here we investigate the problem of implementing the three-qubit double controlled Z gate in a minimal number of steps, where each step is defined as evolution generated by a squared angular momentum operator about a different axis. We prove that at least three such steps are necessary, and numerical optimization of the standard fidelity demonstrates that six steps are sufficient. We seek a general invariant theory approach to extend our proof of necessity to six steps, and classify three-qubit gates according to their complexity in terms of J^2 evolutions.

(Session 5 : Thursday from 5:00 - 7:00 pm)