We review a time-dependent version of the Schrieffer-Wolff transformation that accounts for real-time control of system parameters, soon to be rendered possible on a broad basis due to technical progress. The dispersive regime of N multilevel systems coupled to a cavity via a Jaynes-Cummings interaction is extended to the most general case. As a concrete example we rigorously apply the technique to dispersive two-qubit gates in a superconducting architecture, showing that fidelities based on previous models are off by up to 10−2, which is certainly relevant for high-fidelity gates compatible with fault-tolerant quantum information devices. A closed analytic form for the error depending on the target evolution closes our work.
@article{arxiv.1611.02490,
title = {Nonadiabatic corrections to fast dispersive multiqubit gates involving Z control},
author = {L. S. Theis and F. K. Wilhelm},
journal= {arXiv preprint arXiv:1611.02490},
year = {2017}
}