Polaron-like effects in a one-dimensional optical lattice

TL;DR

This paper investigates polaron-like effects in a one-dimensional optical lattice with an imbalanced Fermi gas, using advanced computational methods to reveal behaviors similar to three-dimensional experiments and identifying a crossover from quasiparticles to charge-density excitations.

Contribution

It provides the first detailed numerical analysis of polaronic behavior in a 1D optical lattice, bridging experimental observations and theoretical models.

Findings

Qualitative similarity to 3D polaron experiments

Excellent agreement with polaron ansatz in weak interactions

Crossover from quasiparticle to charge-density excitation in strong interactions

Abstract

We study a highly imbalanced Fermi gas in a one-dimensional optical lattice from the polaronic point of view. The time-evolving block decimationg algorithm is used to calculate the ground state and dynamics of the system. We find qualitatively similar polaronic behaviour as in the recent experiment by Schirotzek et al. \cite{Schirotzek2009a} where radio-frequency spectroscopy was used to observe polarons in three-dimensional space. In the weakly interacting limit our exact results are in excellent agreement with a polaron ansatz, and in the strongly interacting limit the results match with an approximative solution of the Bethe ansatz, suggesting a crossover from a quasiparticle to a charge-density excitation regime.