Rostock 2019 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 60: Quantum Gases (Bosons and Fermions) II
Q 60.7: Vortrag
Freitag, 15. März 2019, 12:15–12:30, S HS 037 Informatik
Dynamical variational approach to Bose polarons at finite temperatures — •David Dzsotjan1, Richard Schmidt2, and Michael Fleischhauer1 — 1Department of Physics and Research Centre OPTIMAS, TU Kaiserslautern, Germany — 2Max-Planck Institute for Quantum Optics, Garching, Germany
With recent experiments exploring the behaviour of polarons in quantum gases, there has been a very real motivation to construct theoretical models that give a good description of polarons at temperatures larger than zero. We specifically investigate finite-temperature Bose polarons, i.e., an impurity particle interacting with bosons in a BEC. In our theoretical framework we use a dynamical variational approach to solve the dynamics of a single impurity interacting with the Bogoliubov phonons of a BEC which are initially in a thermal state. We present the model where the temperature dependence is mapped onto a stochastic Hamiltonian that includes impurity-phonon interactions up to the 2-phonon order. The ansatz wavefunction for the phonon state is based on coherent states, allowing for an arbitrary number of exitations in the polaronic system. We subsequently present the numerical results for the polaronic dynamics and excitation spectrum, comparing them to recent experimental findings for an impurity-BEC system in a three-dimensional trap.