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Title: Long-range order in the Bose-Einstein condensation of polaritons

Abstract

We adopt a kinetic theory of polariton nonequilibrium Bose-Einstein condensation to describe the formation of off-diagonal long-range order. The theory accounts properly for the dominant role of quantum fluctuations in the condensate. In realistic situations with optical excitation at high energy, it predicts a significant depletion of the condensate caused by long-wavelength fluctuations. As a consequence, the one-body density matrix in space displays a partially suppressed long-range order and a pronounced dependence on the finite size of the system.

Authors:
;  [1]
  1. Institute of Theoretical Physics, Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)
Publication Date:
OSTI Identifier:
20957781
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter and Materials Physics; Journal Volume: 75; Journal Issue: 11; Other Information: DOI: 10.1103/PhysRevB.75.115326; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BOSE-EINSTEIN CONDENSATION; CONDENSATES; DENSITY MATRIX; EXCITATION; FLUCTUATIONS; KINETIC EQUATIONS; POLARONS; WAVELENGTHS

Citation Formats

Sarchi, D., and Savona, V. Long-range order in the Bose-Einstein condensation of polaritons. United States: N. p., 2007. Web. doi:10.1103/PHYSREVB.75.115326.
Sarchi, D., & Savona, V. Long-range order in the Bose-Einstein condensation of polaritons. United States. doi:10.1103/PHYSREVB.75.115326.
Sarchi, D., and Savona, V. Thu . "Long-range order in the Bose-Einstein condensation of polaritons". United States. doi:10.1103/PHYSREVB.75.115326.
@article{osti_20957781,
title = {Long-range order in the Bose-Einstein condensation of polaritons},
author = {Sarchi, D. and Savona, V.},
abstractNote = {We adopt a kinetic theory of polariton nonequilibrium Bose-Einstein condensation to describe the formation of off-diagonal long-range order. The theory accounts properly for the dominant role of quantum fluctuations in the condensate. In realistic situations with optical excitation at high energy, it predicts a significant depletion of the condensate caused by long-wavelength fluctuations. As a consequence, the one-body density matrix in space displays a partially suppressed long-range order and a pronounced dependence on the finite size of the system.},
doi = {10.1103/PHYSREVB.75.115326},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 11,
volume = 75,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}
  • We have experimentally investigated the formation of off-diagonal long-range order in a gas of ultracold atoms. A magnetically trapped atomic cloud prepared in a highly nonequilibrium state thermalizes and thereby crosses the Bose-Einstein condensation phase transition. The evolution of phase coherence between different regions of the sample is constantly monitored and information on the spatial first-order correlation function is obtained. We observe the growth of the spatial coherence and the formation of long-range order in real time and compare it to the growth of the atomic density. Moreover, we study the evolution of the momentum distribution during the nonequilibrium formationmore » of the condensate.« less
  • It is shown theoretically that Bose condensation of spin-degenerated exciton polaritons results in spontaneous buildup of the linear polarization in emission spectra of semiconductor microcavities and therefore that linear polarization is a good order parameter for the polariton Bose condensation under unpolarized pumping. If spin degeneracy is lifted, an elliptically polarized light is emitted by the polariton condensate. The main axis of the ellipse rotates in time due to self-induced Larmor precession of the polariton condensate pseudospin. The polarization decay time is governed by the dephasing induced by the polariton-polariton interaction and is strongly dependent on the statistics of themore » condensed state. If the elliptical polarization preexists in the system as a result of pumping, the lifetime of the linear part of the polarization is also extremely sensitive to the degree of circular polarization induced in the system by pumping. This decay time can be used to measure the coherence degree of the condensate as a function of the polarization of the emitted light, as opposed to more conventional but harder particle counting experiments of the Hanbury Brown-Twiss type.« less
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