Semiclassical polaron dynamics of impurities in ultracold gases

Abstract

We present a semiclassical treatment of a fermionic impurity coupled to Bogolyubov modes of a BEC. In the lowest order approximation we find a full solution of an initial value problem, which turns out to behave differently in the sub- and supersonic regimes. While in the former case no impurity deceleration is observed, in the latter case non-Markovian dissipation effects kick in resulting in slowing down of the fermion. Although this scenario is compatible with the one offered by an elementary field theoretical picture at weak coupling, the details of the dynamics turn out to be completely different. Fluctuation effects can be taken into account by expansion around the classical path. This allows for estimation of the all-important polaron radius as a function of fermion-boson coupling strength. As an application we calculate the drag force which is exerted by the BEC on the impurity moving with constant velocity $v$. Contrary to the perturbative result, according to which the drag force is $\sim v^4$, it turns out to be proportional to $1/v^2$ in the semiclassical regime.

arXiv comment4 pages, 3 figures

References in corpus (10)

• Many-Body Physics with Ultracold Gases
• BCS-BEC Crossover: From High Temperature Superconductors to Ultracold Superfluids
• Observation of Fermi Polarons in a Tunable Fermi Liquid of Ultracold Atoms
• Resonantly-paired fermionic superfluids
• Feynman path-integral treatment of the BEC-impurity polaron
• Polaron Physics in Optical Lattices
• Bogoliubov-Cerenkov radiation in a Bose-Einstein condensate flowing against an obstacle
• Quantum flutter of supersonic particles in one-dimensional quantum liquids
• Feshbach spectroscopy and scattering properties of ultracold Li+Na mixtures
• "Cherenkov radiation" of a sound in a Bose-condensed gas

Cited by in corpus (12)

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• Bloch oscillations of bosonic lattice polarons
• Feynman path-integral treatment of the Bose polaron beyond the Fröhlich model
• New theoretical approaches to Bose polarons
• Effective Potentials Generated by Field Interaction in the Quasi-Classical Limit
• Quantum Cherenkov transition of finite momentum Bose polarons
• Spectral flow of trimer states of two heavy impurities and one light condensed boson
• Creation of excitations from a uniform impurity motion in the condensate
• Dynamical response of ultracold interacting fermion-boson mixtures
• Spectral weight suppression in response functions of ultracold fermion-boson mixtures