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Direct Measurement of Decoherence for Entanglement between a Photon and Stored Atomic Excitation

de Riedmatten, H. and Laurat, J. and Chou, C. W. and Schomburg, E. W. and Felinto, D. and Kimble, H. J. (2006) Direct Measurement of Decoherence for Entanglement between a Photon and Stored Atomic Excitation. Physical Review Letters, 97 (11). Art. No. 113603. ISSN 0031-9007. doi:10.1103/PhysRevLett.97.113603.

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Violations of a Bell inequality are reported for an experiment where one of two entangled qubits is stored in a collective atomic memory for a user-defined time delay. The atomic qubit is found to preserve the violation of a Bell inequality for storage times up to 21 µs, 700 times longer than the duration of the excitation pulse that creates the entanglement. To address the question of the security of entanglement-based cryptography implemented with this system, an investigation of the Bell violation as a function of the cross correlation between the generated nonclassical fields is reported, with saturation of the violation close to the maximum value allowed by quantum mechanics.

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Additional Information:© 2006 The American Physical Society. (Received 29 June 2006; published 14 September 2006) We gratefully acknowledge our ongoing collaboration with Dr. S.J. van Enk. This work was supported by the DTO of the DNI and by the NSF. J.L. acknowledges financial support from the EU (Marie Curie Fellowship), and D.F. from CNPq (Brazilian agency).
Funding AgencyGrant Number
Department of National IntelligenceUNSPECIFIED
Marie Curie FellowshipUNSPECIFIED
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)UNSPECIFIED
Issue or Number:11
Record Number:CaltechAUTHORS:RIEprl06
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5354
Deposited By: Archive Administrator
Deposited On:13 Oct 2006
Last Modified:08 Nov 2021 20:24

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