Hannover 2016 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 22: Quantum Gases: Bosons II
Q 22.8: Vortrag
Dienstag, 1. März 2016, 16:15–16:30, e001
Dynamics of Bose polarons in a BEC — •Fabian Grusdt1, Yulia Shchadilova1, Richard Schmidt1,2, and Eugene Demler1 — 1Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA — 2ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA
When neutral impurity atoms are placed in a Bose-Einstein condensate (BEC), they become dressed by a cloud of phonons and form a polaron. We calculate the spectral function of the impurity, which serves as a fingerprint of polarons in experiments with strongly imbalanced atomic mixtures. We also study the dynamics of polaron formation in the time domain, after a sudden quench of the interaction strength which can be realized using Feshbach resonances. For finite initial velocities of the impurity atoms we predict strong deceleration for long times and find non-trivial transient polaron trajectories.
We analyze the BEC polaron using an extension of the renormalization group (RG) approach [Grusdt et al., Sci.Rep.5:12124, 2015] to far-from equilibrium dynamics. Fröhlich polarons are considered first, but we also apply the RG method to go beyond the Fröhlich approximation. This is necessary to describe experiments in the strong-coupling regime.