# Two independent photon pairs versus four-photon entangled states in parametric down conversion

Authors: | H De Riedmatten, V Scarani, I Marcikic, A Acin, W Tittel, H Zbinden, N Gisin |

Journal: | Journal of Modern Optics 51, 1637–1649 (2004) |

DOI: | http://dx.doi.org/10.1080/09500340310001654991 |

Abstract: | We study the physics of four-photon states generated in spontaneous parametric down-conversion with a pulsed pump field. In the limit where the coherence time of the photons t©(ph) is much shorter than the duration of the pump pulse Deltat, the four photons can be described as two independent pairs. In the opposite limit, the four photons are in a four-particle entangled state. Any intermediate case can be characterized by a single parameter chi, which is a function of t©(ph)/Deltat. We present a direct measurement of chi through a simple experimental set-up. The full theoretical analysis is also provided. |

File: | jmodoptpublished.pdf |

# BibTeX Source

@ARTICLE{DeRiedmatten2004,
author = {De Riedmatten, H. and Scarani, V. and Marcikic, I. and Acin, A. and
Tittel, W. and Zbinden, H. and Gisin, N.},
title = {Two independent photon pairs versus four-photon entangled states
in parametric down conversion},
journal = {Journal of Modern Optics},
year = {2004},
volume = {51},
pages = {1637--1649},
number = {11},
abstract = {We study the physics of four-photon states generated in spontaneous
parametric down-conversion with a pulsed pump field. In the limit
where the coherence time of the photons t(c)(ph) is much shorter
than the duration of the pump pulse Deltat, the four photons can
be described as two independent pairs. In the opposite limit, the
four photons are in a four-particle entangled state. Any intermediate
case can be characterized by a single parameter chi, which is a function
of t(c)(ph)/Deltat. We present a direct measurement of chi through
a simple experimental set-up. The full theoretical analysis is also
provided. },
doi = {10.1080/09500340310001654991},
owner = {cc},
sn = {0950-0340},
timestamp = {2010.08.20},
ut = {WOS:000222181300005}
}