Measurement-induced two-qubit entanglement in a bad cavity: Fundamental and practical considerations

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Brian Julsgaard and Klaus Mølmer


DOI: 10.1103/PhysRevA.85.032327
PACS: 03.67.Bg, 42.50.Pq, 42.50.Lc, 03.65.Ta

An entanglement-generating protocol is described for two qubits coupled to a cavity field in the bad-cavity limit. By measuring the amplitude of a field transmitted through the cavity, an entangled spin-singlet state can be established probabilistically. Both fundamental limitations and practical measurement schemes are discussed, and the influence of dissipative processes and inhomogeneities in the qubits are analyzed. The measurement-based protocol provides criteria for selecting states with an infidelity scaling linearly with the qubit-decoherence rate.