Generation of macroscopic superposition states in ring superlattices

TL;DR

This paper proposes a method to generate macroscopic superposition states in non-uniform ring lattices of ultracold bosons, improving robustness and applicability over previous uniform lattice schemes.

Contribution

It demonstrates that slightly non-uniform ring lattices facilitate the creation of superposition states with better energy gaps and reduced sensitivity to detunings, not limited by filling factors.

Findings

Energy gap decreases less with particle number in non-uniform lattices

Reduced sensitivity to detuning from critical rotation frequency

Proposed detection via time-of-flight imaging and correlation measurements

Abstract

Ultracold bosons in rotating ring lattices have previously been shown to form macroscopic superpositions of different quasi-momentum states. We demonstrate that the generation of such kind of states using slightly non-uniform ring lattices has several advantages: the energy gap decreases less severely with the number of particles, the sensitivity to detunings from the critical rotation frequency is reduced, and the scheme is not limited to commensurate filling. We show that different quasi-momentum states can be distinguished in time-of-flight absorption imaging and propose to probe correlations via the many-body oscillations induced by a sudden change in the rotation frequency.