Fast Non-Adiabatic Gates and Quantum Algorithms on the Kane Quantum Computer in the Presence of Dephasing.

We propose and find pulse sequences for non-adiabatic two-qubit gates (CNOT, swap and controlled Z gates) for the Kane silicon-based electron mediated nuclear spin quantum computer architecture. These quantum gates are simpler, with higher fidelity and faster than existing proposals. Any two qubit gate may be implemented using similar pulse sequences. In this paper, we investigate the effect of decoherence on the operation of these quantum gates and some simple algorithms for a variety of dephasing rates. Our model shows that conservative estimates of the dephasing rates in the Kane architecture give gate fidelities comparable to that required for fault tolerant quantum computing. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]