Volume 88, Number 2, October 2009
Article Number 20003
Number of page(s) 6
Section General
Published online 27 October 2009
EPL, 88 (2009) 20003
DOI: 10.1209/0295-5075/88/20003

Emergence of entanglement out of a noisy environment: The case of microcavity polaritons

S. Portolan1, 2, O. Di Stefano3, S. Savasta3 and V. Savona1

1   Institute of Theoretical Physics, Ecole Polytechnique Fédérale de Lausanne EPFL - CH-1015 Lausanne, Switzerland
2   CEA/CNRS/UJF Joint Team “Nanophysics and Semiconductors”, Institut Néel, CNRS BP 166, 25 rue des Martyrs, 38042 Grenoble Cedex 9, France, EU
3   Dipartimento di Fisica della Materia e Ingegneria Elettronica, Università di Messina Salita Sperone 31, I-98166 Messina, Italy, EU

received 25 September 2009; accepted in final form 8 October 2009; published October 2009
published online 27 October 2009

We show theoretically that polariton pairs with a high degree of polarization entanglement can be produced through parametric scattering. We demonstrate that entanglement can emerge in coincidence experiments, even at low excitation densities where the dynamics is dominated by incoherent photoluminescence. Our analysis is based on a microscopic quantum statistical approach that treats coherent and incoherent processes on an equal footing, thus allowing for a quantitative assessment of the amount of entanglement under realistic experimental conditions. This result puts forward the robustness of pair correlations in solid-state devices, even when noise dominates one-body properties. In particular, we propose an operational method to measure the entanglement of formation, out of a dominant time-dependent noise background, without any need for post-processing. Our study provides a suggestive perspective towards hybrid all-optical quantum devices where quantum information can be efficiently generated and controlled within the same structure.

03.67.Bg - Entanglement production and manipulation.
71.35.Gg - Exciton-mediated interactions.
71.36.+c - Polaritons (including photon-phonon and photon-magnon interactions).

© EPLA 2009