Observation of $1/k^4$-tails after expansion of Bose-Einstein Condensates with impurities

Abstract

We measure the momentum density in a Bose-Einstein condensate (BEC) with dilute spin impurities after an expansion in the presence of interactions. We observe tails decaying as $1/k^4$ at large momentum $k$ in the condensate and in the impurity cloud. These algebraic tails originate from the impurity-BEC interaction, but their amplitudes greatly exceed those expected from two-body contact interactions at equilibrium in the trap. Furthermore, in the absence of impurities, such algebraic tails are not found in the BEC density measured after the interaction-driven expansion. These results highlight the key role played by impurities when present, a possibility that had not been considered in our previous work [Phys. Rev. Lett. 117, 235303 (2016)]. Our measurements suggest that these unexpected algebraic tails originate from the non-trivial dynamics of the expansion in the presence of impurity-bath interactions.

arXiv comment6 pages, 6 figures

References in corpus (35)

• Kondo Physics in a Single Electron Transistor
• A Tunable Kondo Effect in Quantum Dots
• Colloquium: The transport properties of graphene: An introduction
• Large momentum part of fermions with large scattering length
• Quantum dynamics of a single, mobile spin impurity
• Defects in correlated metals and superconductors
• Observation of Attractive and Repulsive Polarons in a Bose-Einstein Condensate
• Bose polarons in the strongly interacting regime
• Polarons, Dressed Molecules, and Itinerant Ferromagnetism in ultracold Fermi gases
• Froehlich Polaron and Bipolaron: Recent Developments
• A trapped single ion inside a Bose-Einstein condensate
• Quantum dynamics of impurities in a 1D Bose gas
• Dynamics of a cold trapped ion in a Bose-Einstein condensate
• Motion of a heavy impurity through a Bose-Einstein condensate
• Localization of bosonic atoms by fermionic impurities in a 3d optical lattice
• Suppression and enhancement of impurity scattering in a Bose-Einstein condensate
• Quantum transport through a Tonks-Girardeau gas
• Bose polarons near quantum criticality
• Coupling a single electron to a Bose-Einstein condensate
• Quantum depletion of a homogeneous Bose-Einstein condensate
• Non-equilibrium quantum dynamics and formation of the Bose polaron
• Single Atom Cooling by Superfluid Immersion: A Non-Destructive Method for Qubits
• Momentum-resolved observation of thermal and quantum depletion in an interacting Bose gas
• Interaction of Impurity Atoms in Bose-Einstein-Condensates
• Universal aspects of a strongly interacting impurity in a dilute Bose condensate
• Neutral Impurities in a Bose-Einstein Condensate for Simulation of the Fröhlich-Polaron
• Quantum behavior of a heavy impurity strongly coupled to a Bose gas
• Ultracold collisions of metastable helium atoms
• Observation of pairs of atoms at opposite momenta in an equilibrium interacting Bose gas
• Single-atom aided probe of the decoherence of a Bose-Einstein condensate
• Evidence for Bosonization in a three-dimensional gas of SU($N$) fermions
• Single-atom-resolved probing of lattice gases in momentum space
• Fast production of Bose-Einstein condensates of metastable Helium
• Expansion of harmonically trapped interacting particles and time dependence of the contact
• On the survival of the quantum depletion of a condensate after release from a magnetic trap

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