Single-Step Implementation of Universal Quantum Gates
I. A. Grigorenko, Dmitri V. Khveshchenko · Physical Review Letters · 2005
We construct optimized implementations of the controlled-NOT and other universal two-qubit gates that, unlike many of the previously proposed protocols, are carried out in a single step. The new protocols require tunable interqubit couplings but, in return, show a significant improvement in the quality of gate operations. We make specific predictions for coupled Josephson junction qubits and compare them with the results of recent experiments.