Neutral impurities in a Bose-Einstein condensate for simulation of the Fröhlich-polaron

Hohmann, Michael; Kindermann, Farina; Gänger, Benjamin; Lausch, Tobias; Mayer, Daniel; Schmidt, Felix; Widera, Artur

doi:10.1140/epjqt/s40507-015-0036-y

Cited by 54 publications

(60 citation statements)

References 58 publications

(68 reference statements)

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“…We subsequently remove the Rb cloud from the trap and record the atomic position with fluorescence imaging (Fig. 1(b)) [17,18]. The spatial distribution for any fixed time is determined by accumulating atomic positions over about 600 realizations.…”

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confidence: 99%

Individual Tracer Atoms in an Ultracold Dilute Gas

et al. 2017

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Understanding the motion of a tracer particle in a rarefied gas is of fundamental and practical importance. We report the experimental investigation of individual Cs atoms impinging on a dilute cloud of ultracold Rb atoms with variable density. We study the nonequilibrium relaxation of the initial nonthermal state and detect the effect of single collisions which has eluded observation so far. We show that after few collisions, the measured spatial distribution of the light tracer atoms is correctly described by a generalized Langevin equation with a velocity-dependent friction coefficient, over a large range of Knudsen numbers.

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confidence: 99%

Individual Tracer Atoms in an Ultracold Dilute Gas

et al. 2017

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“…Given the clean and highly controllable nature of condensates, they allow a study of the fundamental physics of impurities, which is paramount to creating models of realistic condensed matter systems, which are never truly impurity or defect-free. By now impurities have been used to investigate the atomic density distribution [11], as well as exotic quasi-particles such as Fröhlich polarons [12]. These results show that impurities are very robust and reliable tools to investigate the underlying condensate behaviour, and many proposals for further investigations exist [14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 96%

“…Studying impurities in Bose-Einstein condensates (BECs) is a promising and rich topic and the first experiments in this area have recently been carried out [11][12][13]. Given the clean and highly controllable nature of condensates, they allow a study of the fundamental physics of impurities, which is paramount to creating models of realistic condensed matter systems, which are never truly impurity or defect-free.…”

Section: Introductionmentioning

confidence: 99%

Topological defect dynamics of vortex lattices in Bose-Einstein condensates

O’Riordan

Busch

2016

Phys. Rev. A

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Vortex lattices in rapidly rotating Bose-Einstein condensates are systems of topological excitations that arrange themselves into periodic patterns. Here we show how phase-imprinting techniques can be used to create a controllable number of defects in these lattices and examine the resulting dynamics. Even though we describe our system using the mean-field Gross-Pitaevskii theory, the full range of many particle effects among the vortices can be studied. In particular we find the existence of localized vacancies that are quasi-stable over long periods of time, and characterize the effects on the background lattice through use of the orientational correlation function, and Delaunay triangulation.

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“…We interface a quantum gas with individually controlled impurities to realize a model system for impurity physics. Experimentally, we immerse single neutral cesium atoms (Cs) in a pure ultracold cloud of rubidium atoms (Rb) using advanced optical trapping and cooling techniques . Single Cs atoms act as the impurity species and undergo cold collisions with their Rb environment, that is, the bath, thus allowing to investigate single‐atom interaction via the exchange of momentum, energy, or angular momentum.…”

Section: Introductionmentioning

confidence: 99%

“…Experimentally, we immerse single neutral cesium atoms (Cs) in a pure ultracold cloud of rubidium atoms (Rb) using advanced optical trapping and cooling techniques. [23,24] Single Cs atoms act as the impurity species and undergo cold collisions with their Rb environment, that is, the bath, thus allowing to investigate single-atom interaction via the exchange of momentum, energy, or angular momentum. The behavior of impurities in the ultracold bath can be very diverse, depending on internal as well as motional states of the atoms.…”

Section: Introductionmentioning

confidence: 99%

Motional and Spin Dynamics of Individual Neutral Impurities in an Ultracold Gas

Schmidt¹,

Mayer²,

Lausch³

et al. 2019

Physica Status Solidi (b)

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Recent studies on the dynamics of single, neutral impurities immersed in an ultracold gas are reviewed. This paradigmatic model system is realized by the controlled doping of single Caesium atoms into an ultracold Rubidium gas. Interaction between the impurity and the gas in both the motional and internal degrees of freedom is studied for a broad range of bath temperatures in the thermal and quantum‐degenerate regime. Tracing single‐atom diffusion it is found that, even for a granular bath, where the assumption of a continuous medium is not fulfilled, a modified Langevin equation yields excellent predictions for tracer diffusion. Numerical modeling of impurity dynamics in a three‐dimensional superfluid bath shows the emergence of a prethermalized state for intermediate times due to the existence of a superfluid critical momentum, while for lower dimensions the effect of thermal phonons dominates and obstructs the formation of such nonthermal states. Finally, unleashing the quasi‐spin degree of freedom, the authors observe and control spin‐exchange dynamics between individual impurities and the bath. Moreover, a regime of sympathetic impurity cooling is realized, where the internal‐state coherence of the impurity is preserved. In the future, control over the motional and spin‐degree of freedom will enable using individual impurities as thermalized, localized, minimally invasive quantum probes for a quantum fluid.

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Neutral impurities in a Bose-Einstein condensate for simulation of the Fröhlich-polaron

Cited by 54 publications

References 58 publications

Individual Tracer Atoms in an Ultracold Dilute Gas

Individual Tracer Atoms in an Ultracold Dilute Gas

Topological defect dynamics of vortex lattices in Bose-Einstein condensates

Motional and Spin Dynamics of Individual Neutral Impurities in an Ultracold Gas

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