Designing Robust Unitary Gates: Application to Concatenated Composite Pulse

Tsubasa Ichikawa, Masamitsu Bando, Yasushi Kondo, Mikio Nakahara

Published 2011-05-04, updated 2011-11-23Version 3

We propose a simple formalism to design unitary gates robust against given systematic errors. This formalism generalizes our previous observation [Y. Kondo and M. Bando, J. Phys. Soc. Jpn. 80, 054002 (2011)] that vanishing dynamical phase in some composite gates is essential to suppress amplitude errors. By employing our formalism, we naturally derive a new composite unitary gate which can be seen as a concatenation of two known composite unitary operations. The obtained unitary gate has high fidelity over a wider range of the error strengths compared to existing composite gates.