Logic-qubit controlled-NOT gate of decoherence-free subspace with nonlinear quantum optics
Chunyan Li, Zu-Rong Zhang, Shi‐Hai Sun, Mu-Sheng Jiang, Lin-Mei Liang · Journal of the Optical Society of America B · 2013
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.