Polarons and Bose decondensation: A self-trapping approach

Lee, Derek K. K.; Gunn, J. M. F.

doi:10.1103/physrevb.46.301

Cited by 19 publications

(30 citation statements)

References 12 publications

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“…(51) is a generalization of Eqs. (22), (23) in Ref. [38] (up to a factor of two), where they were derived in the context of dynamics of grey solitons.…”

Section: Depleton Dynamics At Zero Temperature Radiative Correctionsmentioning

confidence: 99%

Dynamics and Bloch oscillations of mobile impurities in one-dimensional quantum liquids

2012

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We study dynamics of a mobile impurity moving in a one-dimensional quantum liquid. Such an impurity induces a strong non-linear depletion of the liquid around it. The dispersion relation of the combined object, called depleton, is a periodic function of its momentum with the period 2πn, where n is the mean density of the liquid. In the adiabatic approximation a constant external force acting on the impurity leads to the Bloch oscillations of the impurity around a fixed position. Dynamically such oscillations are accompanied by the radiation of energy in the form of phonons. The ensuing energy loss results in the uniform drift of the oscillation center. We derive exact results for the radiation-induced mobility as well as the thermal friction force in terms of the equilibrium dispersion relation of the dressed impurity (depleton). These results show that there is a wide range of external forces where the (drifted) Bloch oscillations exist and may be observed experimentally.

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“…(51) is a generalization of Eqs. (22), (23) in Ref. [38] (up to a factor of two), where they were derived in the context of dynamics of grey solitons.…”

Section: Depleton Dynamics At Zero Temperature Radiative Correctionsmentioning

confidence: 99%

Dynamics and Bloch oscillations of mobile impurities in one-dimensional quantum liquids

2012

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“…This has led to an investigation of the change of the properties of the bare impurities as a result of the interactions with the condensate (such as the effective interaction [7,8] and the effective mass [9][10][11]) and a study of the self-trapping of the impurity [12,13]. Also, the system of a spin-down fermion in a sea of spin-up fermions, usually indicated as the Fermi polaron, has been investigated, which resulted in good agreement between theory [14,15] and experiments [16,17].…”

Section: Introductionmentioning

confidence: 99%

Response of the polaron system consisting of an impurity in a Bose-Einstein condensate to Bragg spectroscopy

Casteels¹,

Tempere²,

Devreese³

2011

Phys. Rev. A

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We expand the existing polaron response theory, expressed within the Mori-Zwanzig projection operator formalism applicable for the transfer of arbitrary energy and zero momentum, for the case of finite momentum exchange. A general formula is then derived that can be used to calculate the response of a system to a probe that transfers both momentum and energy to the system. The main extension of the existing polaron response theory is the finite momentum exchange, which was not needed until now, since it is negligible for optical absorption. However, this formalism is needed to calculate the response of the polaronic system consisting of an impurity in a Bose-Einstein condensate (BEC) to Bragg spectroscopy. We show that the well-known features that appear in the optical absorption of the solid-state Fröhlich polaron are also present in the Bragg response of the BEC-impurity polaron. The f-sum rule is written in a form suitable to provide an independent consistency test for our results. The effect of lifetime broadening on the BEC-impurity spectrum is examined. The results derived here are discussed in the framework of an experimental realization consisting of a lithium impurity in a sodium condensate.

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“…Recently, the experimental realization of impurities in a BEC [3,4] and the possibility to produce quantum degenerate atomic mixtures [5,6] have generated renewed interest in the physics of impurities. In particular, it was pointed out that single atoms can get trapped in the localized distortion of the BEC that is induced by the impurity-BEC interaction [7][8][9][10][11]. More precisely, the impurity becomes self-trapped if its interaction with the BEC is sufficiently strong to compensate for the high kinetic energy of a localized state, an effect akin to the self-trapping of impurities in liquid helium [1].…”

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confidence: 99%

“…In one dimension Eq. (9) admits the exact solution [7,20] χ λ (x) = (2λ) −1/2 sech(x/λ), with the localization length λ = 2/ζ and the energy ε ′ = −ζ 2 /8. In addition, numerical solutions of Eq.…”

mentioning

confidence: 99%

Self-trapping of impurities in Bose-Einstein condensates: Strong attractive and repulsive coupling

2008

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We study the interaction-induced localization -the so-called self-trapping -of a neutral impurity atom immersed in a homogeneous Bose-Einstein condensate (BEC). Based on a Hartree description of the BEC we show that -unlike repulsive impurities -attractive impurities have a singular ground state in 3d and shrink to a point-like state in 2d as the coupling approaches a critical value β ⋆ . Moreover, we find that the density of the BEC increases markedly in the vicinity of attractive impurities in 1d and 2d, which strongly enhances inelastic collisions between atoms in the BEC. These collisions result in a loss of BEC atoms and possibly of the localized impurity itself.

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Polarons and Bose decondensation: A self-trapping approach

Cited by 19 publications

References 12 publications

Dynamics and Bloch oscillations of mobile impurities in one-dimensional quantum liquids

Dynamics and Bloch oscillations of mobile impurities in one-dimensional quantum liquids

Response of the polaron system consisting of an impurity in a Bose-Einstein condensate to Bragg spectroscopy

Self-trapping of impurities in Bose-Einstein condensates: Strong attractive and repulsive coupling

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