Quantum theory for generation of nonclassical photon pairs by a medium with collective atomic memory

Journal Article · Sat Oct 15 04:00:00 EDT 2005 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.72.043806· OSTI ID:20718798

Sisakyan, Narek; Malakyan, Yuri ^[1]

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1. Institute for Physical Research, Armenian National Academy of Sciences, Ashtarak-2, 378410 (Armenia)

We present the quantum theory for creation of collective atomic memory and generation of nonclassically correlated photon pairs from an ensemble via the protocol of Duan et al. [Nature (London) 414, 413 (2001)]. The temporal evolution of photon numbers, photon statistics, and cross-correlation between the Stokes and anti-Stokes fields is found by solving the equation of motion for atomic spin-wave excitations. We consider a low-finesse cavity model with collectively enhanced signal-to-noise ratio, which remains still considerably large in the free-space limit. Our results describe analytically the dependence of quantum correlations on spin decoherence time and time delay between the write and read lasers and reproduce the observed data very well including the generated pulse shapes, strong violation of Cauchy-Schwarz inequality and conditional generation of anti-Stokes single-photon pulse. The approach we developed may be used also for quantum description of storage and retrieval of quantum information, especially when the statistical properties of nonclassical pulses are studied.

• OSTI ID: 20718798
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 4 Vol. 72; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
CORRELATIONS
DATA TRANSMISSION
EQUATIONS OF MOTION
EXCITATION
INFORMATION THEORY
LASERS
OPTICS
PHOTONS
PULSES
QUANTUM INFORMATION
QUANTUM MECHANICS
SIGNAL-TO-NOISE RATIO
SPIN
SPIN WAVES
STATISTICS
TIME DELAY