Generation of an arbitrary logic W state with cross-Kerr nonlinearities

Abstract

Environmental noise is a big obstacle in quantum communication and computation. Quantum error code (QEC) technology can resist the photon transmission loss and decoherence error caused by the environmental noise and has great application potential in future quantum communication and computation fields. The generation of logic qubits or logic entanglement is the important first step of the QEC. The logic W state, which replaces each physical qubit in a physical W state with a logic qubit, may be highly robust against photon loss and errors, so that it may have big application potential. In this paper, we propose an efficient scheme to generate an arbitrary logic W state with the help of cross-Kerr nonlinearities. Our protocol only requires a physical W state and some auxiliary single photons, and can deterministically generate a general logic W state based on the homodyne measurement results. Our logic W state generation protocol may be useful in future quantum information processing based on the logic W state.