Quantum Theory for Generation of Nonclassical Photon Pairs by a Medium with Coherent Atomic Memory
arXiv:quant-ph/0503186 · doi:10.1103/PhysRevA.72.043806
Abstract
We present a fully quantum mechanical treatment of recent experiments on creation of collective quantum memory and generation of non-classically correlated photon pairs from an atomic ensemble via the protocol of Duan et al. [Nature {\bf 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 theory we developed may serve as a basic approach for quantum description of storage and retrieval of quantum information, especially when the statistical properties of non-classical pulses are studied.
arXiv comment9 pages, 3 figures, Revtex
References in corpus (13)
- Quantum Cryptography
- Long-distance quantum communication with atomic ensembles and linear optics
- Quantum state transfer and entanglement distribution among distant nodes in a quantum network
- Storage of light in atomic vapor
- Dark-State Polaritons in Electromagnetically Induced Transparency
- Scalable photonic quantum computation through cavity-assisted interaction
- Generation of Nonclassical Photon Pairs for Scalable Quantum Communication with Atomic Ensembles
- Entanglement of Atomic Ensembles by Trapping Correlated Photon States
- Single-Photon Generation from Stored Excitation in an Atomic Ensemble
- Single Photons on Pseudo-Demand from Stored Parametric Down-Conversion
- Shaping quantum pulses of light via coherent atomic memory
- Temporal Dynamics of Photon Pairs Generated by an Atomic Ensemble
- Nonclassical photon pairs generated from a room-temperature atomic ensemble