Resonantly Enhanced Tunneling and Transport of Ultracold Atoms on Tilted Optical Lattices

TL;DR

This paper studies resonantly enhanced tunneling of ultracold bosons in tilted optical lattices, revealing quantum critical behavior and proposing a controllable transport scheme for atomtronic applications.

Contribution

It introduces an analytical approach for incommensurate fillings and demonstrates a new transport scheme for optical lattice-based atomtronic devices.

Findings

Maximum center of mass oscillation amplitude at quantum critical point

Good agreement between analytical and numerical results at low fillings

Proposed a controllable transport scheme for atomtronic devices

Abstract

We investigate the resonantly enhanced tunneling dynamics of ultracold bosons loaded on a tilted 1-D optical lattice, which can be used to simulate a chain of Ising spins and associated quantum phase transitions. The center of mass motion after a sudden tilt both at commensurate and incommensurate fillings is obtained via analytic, time-dependent exact diagonalization and density matrix renormalization group methods (adaptive t-DMRG). We identify a maximum in the amplitude of the center of mass oscillations at the quantum critical point of the effective spin system. For the dynamics of incommensurate systems, which cannot be mapped to a spin model, we develop an analytical approach in which the time evolution is obtained by projecting onto resonant families of small clusters. We compare the results of this approach at low fillings to the exact time evolution and find good agreement even at filling factors as large as 2/3. Using this projection onto small clusters, we propose a controllable transport scheme applicable in the context of Atomtronic devices on optical lattices (`slinky scheme').