Hannover 2013 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 56: Poster III
Q 56.5: Poster
Donnerstag, 21. März 2013, 16:00–18:30, Empore Lichthof
Non-equilibrium Functional Renormalization for Driven Open Many-Body Quantum Systems — •Lukas M. Sieberer1, Ehud Altman2, Sebastian D. Huber3, and Sebastian Diehl1,4 — 1Institute for Theoretical Physics, University of Innsbruck, 6020 Innsbruck, Austria — 2Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel — 3Institute for Theoretical Physics, ETH Zurich, 8093 Zurich, Switzerland — 4Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, 6020 Innsbruck, Austria
We study phase transitions in bosonic driven-dissipative systems with competing dissipative and unitary dynamics, describing a natural long-wavelength model for pumped quantum systems such as exciton-polariton condensates or cold atomic systems with optical Feshbach resonances. In three spatial dimensions, these systems thermalize at low frequencies and exhibit universal critical behavior governed by an interacting Wilson-Fisher fixed point. We identify a new and independent non-equilibrium critical exponent, measuring the fade-out of the microscopic competition of unitary and dissipative dynamics.
The starting point of our analysis is a description of the driven-dissipative dynamics by a Markovian many-body master equation which we map to a Keldysh functional integral partition function. The Keldysh technique provides an excellent framework to put into practice a functional renormalization group approach for the study of criticality in non-equilibrium stationary states.