Phonon resonances in atomic currents through Bose-Fermi mixtures in optical lattices

Bruderer, M.; Johnson, T. H.; Clark, Stephen R. L.; Jaksch, Dieter; Posazhennikova, Anna; Belzig, Wolfgang

doi:10.1103/physreva.82.043617

Cited by 20 publications

(32 citation statements)

References 39 publications

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“…More precisely, we consider an M -site system with box boundary conditions or a suitably flat bottomed potential (see [41] for an example of a box trap realized in an experiment). As in [8] we expect our system to share its bulk behavior with the experimentally important case of an additional harmonic trap, provided that the trap is sufficiently shallow. A realization of the model may also draw on recent experimental successes in trapping atoms in species-specific optical lattices [11,42,43].…”

Section: Detailed Model and Measuring Proceduresmentioning

confidence: 85%

“…The system is identical to that considered in [8] which focussed on a superfluid environment (U b /J b ≪ 1), whereby the impurity and Bose gas together mimicked the electron-phonon interaction. However, the control and flexibility of an optical lattice setup allows for the creation of a strongly-interacting Bose gas (U b /J b ≫ 1), the regime we explore in this article.…”

Section: Detailed Model and Measuring Proceduresmentioning

confidence: 99%

“…The advantage of a cold atom and optical lattice setup is its ability to realize idealized Hamiltonians and fine-tune interactions over large parameter regimes, often beyond those found in condensed matter systems [2]. In this vein, we extend the large body of theoretical work on the transport of an impurity (partly subject to static forcing) through a superfluid [3][4][5][6][7][8][9] by considering strongly-interacting bosons in one dimension up to the Mott insulator and Tonks-Girardeau limits, whereupon the bosons exhibit fermionic characteristics [10]. Recently, impurity transport in this context has received interest due to its successful realization by two experiments, one using a species specific dipole potential [11] and another using gravity to provide a static force for the impurities [12,13].…”

Section: Introductionmentioning

confidence: 99%

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Impurity transport through a strongly interacting bosonic quantum gas

et al. 2011

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Using near-exact numerical simulations we study the propagation of an impurity through a onedimensional Bose lattice gas for varying bosonic interaction strengths and filling factors at zero temperature. The impurity is coupled to the Bose gas and confined to a separate tilted lattice. The precise nature of the transport of the impurity is specific to the excitation spectrum of the Bose gas which allows one to measure properties of the Bose gas non-destructively, in principle, by observing the impurity; here we focus on the spatial and momentum distributions of the impurity as well as its reduced density matrix. For instance we show it is possible to determine whether the Bose gas is commensurately filled as well as the bandwidth and gap in its excitation spectrum. Moreover, we show that the impurity acts as a witness to the cross-over of its environment from the weakly to the strongly interacting regime, i.e., from a superfluid to a Mott insulator or TonksGirardeau lattice gas and the effects on the impurity in both of these strongly-interacting regimes are clearly distinguishable. Finally, we find that the spatial coherence of the impurity is related to its propagation through the Bose gas, giving an experimentally controllable example of noise-enhanced quantum transport.

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Section: Detailed Model and Measuring Proceduresmentioning

confidence: 85%

Section: Detailed Model and Measuring Proceduresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Impurity transport through a strongly interacting bosonic quantum gas

et al. 2011

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“…Additionally, cold-atomic ensembles are well suited to the investigation of nonequilibrium phenomena [39][40][41][42][43] since they are very well isolated from the environment and their parameters can be tuned dynamically. There is thus a growing interest in out-of-equilibrium polaron problems [23,37,37,38,[44][45][46][47][48][49] which remained out of reach in solid-state systems due to short equilibration times.…”

Section: Introductionmentioning

confidence: 99%

Bloch oscillations of bosonic lattice polarons

et al. 2014

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We consider a single-impurity atom confined to an optical lattice and immersed in a homogeneous Bose-Einstein condensate (BEC). Interaction of the impurity with the phonon modes of the BEC leads to the formation of a stable quasiparticle, the polaron. We use a variational mean-field approach to study dispersion renormalization and derive equations describing nonequilibrium dynamics of polarons by projecting equations of motion into mean-field-type wave functions. As a concrete example, we apply our method to study dynamics of impurity atoms in response to a suddenly applied force and explore the interplay of coherent Bloch oscillations and incoherent drift. We obtain a nonlinear dependence of the drift velocity on the applied force, including a sub-Ohmic dependence for small forces for dimensionality d > 1 of the BEC. For the case of heavy impurity atoms, we derive a closed analytical expression for the drift velocity. Our results show considerable differences with the commonly used phenomenological Esaki-Tsu model.

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“…A traditional way of simulating electron-phonon systems with cold atoms is to trap the species representing electrons in an OL and place it in contact with the Bose condensate of another species that provides the phonons [9][10][11][12][13][14][15]. In our case the trapped species represents the ions providing the phonons and the untrapped species represents the electrons.…”

Section: Introductionmentioning

confidence: 99%

Optical lattices with large scattering length: Using few-body physics to simulate an electron-phonon system

Lan

Lobo

2014

Phys. Rev. A

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We propose to go beyond the usual Hubbard model description of atoms in optical lattices and show how few-body physics can be used to simulate many-body phenomena, e.g., an electron-phonon system. We take one atomic species to be trapped in a deep optical lattice at full-filling and another to be untrapped spin-polarized fermions (which do not see the optical lattice) but to have an s-wave contact interaction with the first species. For large positive scattering length on the order of lattice spacing, the usual two-body bound (dimer) states overlap forming giant orbitals extending over the entire lattice, which can be viewed as an "electronic" band for the untrapped species while the trapped atoms become the "ions" with their own on-site dynamics, thereby simulating an electron-phonon system with renormalization of the phonon frequencies and Peierls transitions. This setup requires large scattering lengths but minimizes losses, does not need higher bands, and adds degrees of freedom which cannot easily be described in terms of lattice variables, thus opening up intriguing possibilities to explore interesting physics at the interface between few-body and many-body systems.

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Phonon resonances in atomic currents through Bose-Fermi mixtures in optical lattices

Cited by 20 publications

References 39 publications

Impurity transport through a strongly interacting bosonic quantum gas

Impurity transport through a strongly interacting bosonic quantum gas

Bloch oscillations of bosonic lattice polarons

Optical lattices with large scattering length: Using few-body physics to simulate an electron-phonon system

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