The implementation of an optical system universal logic-qubit controlled-NOT gate of decoherence-free subspaces (DFSs) using the cross-Kerr nonlinearity effect is discussed. Both the control qubit and the target qubit contain two photons, the states of which are DFSs of collective-rotating noise or collective-dephasing noise. A three-qubit parity-check circuit, which is the most important unit of the quantum gate, is proposed first, and only one ancillary photon is needed in our scheme. A single-photon source, linear optical apparatus, and quantum nondemolition detector are used to perform the process. Its efficiency may approach 100% with a feed-forward process. The experimental feasibility of the strategy with current technology is also considered.
© 2013 Optical Society of America
Original Manuscript: April 8, 2013
Manuscript Accepted: April 26, 2013
Published: June 13, 2013
Chun-Yan Li, Zu-Rong Zhang, Shi-Hai Sun, Mu-Sheng Jiang, and Lin-Mei Liang, "Logic-qubit controlled-NOT gate of decoherence-free subspace with nonlinear quantum optics," J. Opt. Soc. Am. B 30, 1872-1877 (2013)