Taming of decoherence-optimal control approach

We carry out an analysis of the system of two coupled qubits, each of which is subject to its own dissipative environment. We find a combination of the inter-qubit couplings that provides for the lowest possible decoherence rates of the two-qubit register. Using this result, we construct optimized implementations of the CNOT and other universal two-qubit gates that, unlike in the most of previously proposed protocols, are carried out in a single step. The new protocols require tunable inter-qubit couplings but, in return, show a significant improvements in the quality of gate operations.