Entanglement swapping between photon pairs is a fundamental building block in schemes using quantum relays or quantum repeaters to overcome the range limits of long-distance quantum key distribution. We develop a closed-form solution for the actual quantum states prepared by realistic entanglement swapping, which takes into account experimental deficiencies due to inefficient detectors, detector dark counts, and multiphoton-pair contributions of parametric down-conversion sources. We investigate how the entanglement present in the final state of the remaining modes is affected by the real-world imperfections. To test the predictions of our theory, comparison with previously published experimental entanglement swapping is provided.
@article{arxiv.0904.1184,
title = {Quantum states prepared by realistic entanglement swapping},
author = {Artur Scherer and Regina B. Howard and Barry C. Sanders and Wolfgang Tittel},
journal= {arXiv preprint arXiv:0904.1184},
year = {2010}
}
Comments
44 pages, 7 figures, Published with minor changes in Phys. Rev. A