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

TL;DR

This paper presents a measurement-based protocol for probabilistically generating entanglement between two qubits in a bad cavity, analyzing fundamental limits, practical measurement schemes, and effects of dissipation and inhomogeneities.

Contribution

It introduces a novel entanglement protocol using cavity transmission measurements and evaluates its fundamental and practical limitations.

Findings

Entanglement can be probabilistically generated via cavity transmission measurement.

Infidelity scales linearly with qubit-decoherence rate under the protocol.

The protocol accounts for dissipative effects and qubit inhomogeneities.

Abstract

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.