Bloch Oscillations in Optical and Zeeman Lattices in the Presence of Spin-Orbit Coupling

TL;DR

This paper investigates how spin-orbit coupling influences Bloch oscillations in optical and Zeeman lattices, revealing controllable atomic motion, oscillation suppression, and period-doubling phenomena linked to band structure crossings.

Contribution

It demonstrates novel effects of spin-orbit coupling on Bloch oscillations, including motion control, suppression, and period-doubling in different lattice types.

Findings

Spin-orbit coupling enables control over atomic motion direction.

Complete suppression of oscillations occurs at specific coupling strengths.

Band crossings lead to period-doubling of Bloch oscillations.

Abstract

We address Bloch oscillations of a spin-orbit coupled atom in periodic potentials of two types: Optical and Zeeman lattices. We show that in optical lattices the spin-orbit coupling allows controlling the direction of atomic motion and may lead to complete suppression of the oscillations at specific values of the coupling strength. In Zeeman lattices the energy bands are found to cross each other at the boundaries of the Brillouin zone, resulting in period-doubling of the oscillations. In all cases, the oscillations are accompanied by rotation of the pseudo-spin, with a dynamics that is determined by the strength of the spin-orbit coupling. The predicted effects are discussed also in terms of a Wannier-Stark ladder, which in optical lattices consist of two mutually-shifted equidistant sub-ladders.