Identifying Entanglement Using Quantum Ghost Interference and Imaging

Milena D’Angelo, Yoon-Ho Kim, Sergei P. Kulik, and Yanhua Shih

Phys. Rev. Lett. 92, 233601 – Published 8 June 2004

Abstract

We report a quantum interference and imaging experiment which allows identifying the entanglement in momentum and position variables of a two-photon system. The measurements show indeed that the uncertainties in the sum of momenta and in the difference of positions of the entangled two-photon satisfy both EPR inequalities $Δ (k_{1} + k_{2}) < \min (Δ k_{1}, Δ k_{2})$ and $Δ (x_{1} - x_{2}) < \min (Δ x_{1}, Δ x_{2})$ . These two inequalities, together, represent a nonclassicality condition. Our measurements provide a direct way to distinguish between quantum entanglement and classical correlation in continuous variables for systems of pairs of photons.

Received 20 August 2003

DOI:https://doi.org/10.1103/PhysRevLett.92.233601

Authors & Affiliations

Milena D’Angelo^1,*, Yoon-Ho Kim^2,†, Sergei P. Kulik^1,‡, and Yanhua Shih¹

¹Department of Physics, University of Maryland, Baltimore County, Baltimore, Maryland, 21250, USA
²Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, 790-784, Korea

^*Electronic address: dmilena1@umbc.edu
^†Electronic address: yoonho@postech.ac.kr
^‡Permanent address: Department of Physics, Moscow State University, Moscow, Russia.

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Vol. 92, Iss. 23 — 11 June 2004

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