Power-law decay of the spatial correlation function in exciton-polariton condensates

Georgios Roumpos*, Michael Lohse, Wolfgang H. Nitsche, Jonathan Keeling, Marzena Hanna Szymanska, Peter B. Littlewood, Andreas Loeffler, Sven Höfling, Lukas Worschech, Alfred Forchel, Yoshihisa Yamamoto

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

110 Citations (Scopus)


We create a large exciton-polariton condensate and employ a Michelson interferometer setup to characterize the short- and long-distance behavior of the first order spatial correlation function. Our experimental results show distinct features of both the two-dimensional and nonequilibrium characters of the condensate. We find that the gaussian short-distance decay is followed by a power-law decay at longer distances, as expected for a two-dimensional condensate. The exponent of the power law is measured in the range 0.9-1.2, larger than is possible in equilibrium. We compare the experimental results to a theoretical model to understand the features required to observe a power law and to clarify the influence of external noise on spatial coherence in nonequilibrium phase transitions. Our results indicate that Berezinskii-Kosterlitz-Thouless-like phase order survives in open-dissipative systems.

Original languageEnglish
Pages (from-to)6467-6472
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number17
Early online date11 Apr 2012
Publication statusPublished - 24 Apr 2012


  • quantum well excitons
  • semiconductor microcavities
  • GAS


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