Bloch oscillations of bosonic lattice polarons

Abstract

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 non-equilibrium dynamics of polarons by projecting equations of motion into mean-field (MF) type wavefunctions. 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 non-linear 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.

25 pages, 12 figures

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Cited by in corpus (9)

• Quantum Brownian Motion with Inhomogeneous Damping and Diffusion
• Lattice polarons across the superfluid to Mott insulator transition
• Effective approach for taking into account interactions of quasiparticles from the low-temperature behavior of a deformed fermion-gas model
• Bloch Oscillations of a Soliton in a 1D Quantum Fluid
• Disorder in order: Localization without randomness in a cold atom system
• Entangling lattice-trapped bosons with a free impurity: impact on stationary and dynamical properties
• Particle zoo in a doped spin chain: Correlated states of mesons and magnons
• Path-Integral Approach to Quantum Acoustics
• Phenomenological model of decaying Bose polarons