# Berlin 2014 – wissenschaftliches Programm

## Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

# Q: Fachverband Quantenoptik und Photonik

## Q 32: Poster: Quantum gases, ultracold atoms and molecules

### Q 32.1: Poster

### Mittwoch, 19. März 2014, 16:30–18:30, Spree-Palais

**Driven-dissipative two-dimensional Bose-Einstein condensation** — Ehud Altman^{1}, John Toner^{2}, •Lukas M. Sieberer^{3,4}, Sebastian Diehl^{3,4}, and Leiming Chen^{5} — ^{1}Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel — ^{2}Department of Physics and Institute of Theoretical Science, University of Oregon, Eugene OR, 97403, U.S.A. — ^{3}Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck, Austria — ^{4}Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck — ^{5}College of Science, The China University of Mining and Technology, Xuzhou Jiangsu, 221116, P.R. China

The non-equilibrium dynamics of driven-dissipative Bose condensates is described by the dissipative stochastic Gross-Pitaevskii equation, which in the long-wavelength limit can be mapped exactly to the Kardar-Parisi-Zhang equation. This mapping allows us to show that for two-dimensional isotropic systems deviations from equilibrium are relevant perturbations in the renormalization group sense, leading ultimately to the destruction of the condensate at the longest scales. This is in stark contrast to the three-dimensional case where thermodynamic properties and long range correlations mimic the behavior of equilibrium systems with truly non-equilibrium phenomena arising in the dynamics only. Effective equilibrium can be established in two-dimensional driven-dissipative condensates only if rotational symmetry is strongly broken. Then the transition to the disordered phase occurs by a standard equilibrium Kosterlitz-Thouless transition.