Erlangen 2018 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 17: Bose-Einstein Condensation (joint session A/Q)

Q 17.8: Talk

Monday, March 5, 2018, 15:45–16:00, K 2.016

Role of thermal phonon scattering for impurity dynamics in low-dimensional BEC — •Tobias Lausch, Artur Widera, and Michael Fleischhauer — TU Kaiserslautern and Forschungszentrum OPTIMAS, Erwin-Schroedinger-Strasse 46, 67663 Kaiserslautern, Germany

Ultracold gases have proven powerful systems to engineer quantum systems, paving the way for quantum simulations of solid state phenomena. An intriguing focus of research lies on impurity systems, aiming on elucidating microscopic properties of thermalization or quasi-particle formation in quantum systems.

We theoretically study the immersion of single impurities into a BEC in different spatial-dimensions and solve a Boltzmann equation to analyze the non-equilibrium dynamics. We find that high order scattering processes, such as two phonon scattering, dominate the impurities cooling dynamics in low dimensional BEC even at low (experimentally accessible) finite temperatures. In fact, these two-phonon scattering processes are the microscopic mechanism reflecting the famous Mermin-Wagner-Hohenberg theorem. Our work undelines the necessity to include higher-order scattering terms in the investigation of low-dimensional impurity physics.