Optimizing quantum gates within decoherence-free subspaces

A scheme for optimizing quantum gates in quantum computation on decoherence-free subspaces using optimal control theory is presented. Compared with the previous scheme, this scheme possesses the following properties: (i) efficiency in finding control sequences, specifically in a system without controllable exchange interaction where the previous method is difficult to handle; (ii) robustness against control errors; and (iii) showing better performance than the robust GRAPE method under stochastic noise. As an application, we work out the control sequences for the NOT, quantum phase, and CNOT gates.

Automated summary

This scheme uses optimal control theory to optimize quantum gates in quantum computation on decoherence-free subspaces, providing efficiency, robustness, and better performance compared to previous methods.