Entanglement fidelity of quantum memories

Abstract

We introduce a figure of merit for a quantum memory which measures the preservation of entanglement between a qubit stored in and retrieved from the memory and an auxiliary qubit. We consider a general quantum memory system consisting of a medium of two level absorbers, with the qubit to be stored encoded in a single photon. We derive an analytic expression for our figure of merit taking into account Gaussian fluctuations in the Hamiltonian parameters, which for example model inhomogeneous broadening and storage time dephasing. Finally we specialize to the case of an atomic quantum memory where fluctuations arise predominantly from Doppler broadening and motional dephasing.

5 pages, 3 figures

References in corpus (14)

• Distributed Entanglement
• Experimental demonstration of quantum memory for light
• Quantum repeaters based on entanglement purification
• Quantum memory for photons: I. Dark state polaritons
• Storage and retrieval of single photons transmitted between remote quantum memories
• Monogamy of entanglement and other correlations
• Direct estimations of linear and non-linear functionals of a quantum state
• Universal Quantum Estimator
• Quantum memory for non-stationary light fields based on controlled reversible inhomogeneous broadening
• Quantum benchmark for storage and transmission of coherent states
• Three-dimensional theory for interaction between atomic ensembles and free-space light
• Tema Con Variazioni: Quantum Channel Capacity
• Efficient quantum memory and entanglement between light and an atomic ensemble using magnetic fields
• Entanglement splitting of pure bipartite quantum states

Cited by in corpus (8)

• Quantum interface between light and atomic ensembles
• Quantum Memories. A Review based on the European Integrated Project "Qubit Applications (QAP)"
• Creating diamond color centers for quantum optical applications
• Efficient spatially-resolved multimode quantum memory
• The connection between holographic entanglement and complexity of purification
• Quantum memory for light via stimulated off-resonant Raman process: beyond the three-level Lambda-scheme approximation
• Decoherence of an $n$-qubit quantum memory
• Entanglement fidelity and measurement of entanglement preserving in quantum processes