Hannover 2020 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 13: Posters: Quantum Optics and Photonics I
Q 13.8: Poster
Monday, March 9, 2020, 16:30–18:30, Empore Lichthof
Dynamical variational approach to Bose polarons at finite temperatures — •David Dzsotjan1, Richard Schmidt2, and Michael Fleischhauer1 — 1TU Kaiserslautern, Kaiserslautern, Germany — 2Max-Planck-Institute of Quantum Optics, Garching, Germany
Polarons appear as the result of interaction between a large number of majority particles and a few impurities. Here, we discuss the interaction of a mobile quantum impurity with a Bose-Einstein condensate of atoms at finite temperature. To describe the resulting Bose polaron formation we apply a dynamical variational approach to an initial thermal gas of Bogoliubov phonons. We study the polaron formation after switching on the interaction, e.g., by a radio-frequency (RF) pulse from a non-interacting to an interacting state (injection spectrum). We calculate the real-time impurity Green's function and discuss its temperature dependence. Furthermore, we determine the RF absorption spectrum and find good agreement with recent experimental observations. We predict temperature-induced shifts and a substantial broadening of spectral lines. The analysis of the real-time Green's function reveals a crossover to a linear temperature dependence of the thermal decay rate of Bose polarons as the unitary interaction regime is approached. We also show the results of our work concerning the polaronic ejection spectrum, i.e., when from a steady-state polaron one transfers the impurity to a state where it no longer interacts with the majority bosons.