Engineering mesoscopic superpositions of superfluid flow

TL;DR

This paper explores the creation and robustness of mesoscopic superpositions of superfluid flow in ultracold atoms, analyzing effects of non-ideal procedures and temperature, and proposing feasible experimental methods.

Contribution

It identifies optimal regimes and procedures for generating robust superpositions of vortex states in ultracold atoms, including strongly-interacting and weakly-interacting regimes.

Findings

Superpositions are most accessible in the Tonks-Girardeau regime.

Adiabatic decrease of interaction strength can produce NOON states.

Creating superpositions with about 100 atoms appears feasible.

Abstract

Modeling strongly correlated atoms demonstrates the possibility to prepare quantum superpositions that are robust against experimental imperfections and temperature. Such superpositions of vortex states are formed by adiabatic manipulation of interacting ultracold atoms confined to a one-dimensional ring trapping potential when stirred by a barrier. Here, we discuss the influence of non-ideal experimental procedures and finite temperature. Adiabaticity conditions for changing the stirring rate reveal that superpositions of many atoms are most easily accessed in the strongly-interacting, Tonks-Girardeau, regime, which is also the most robust at finite temperature. NOON-type superpositions of weakly interacting atoms are most easily created by adiabatically decreasing the interaction strength by means of a Feshbach resonance. The quantum dynamics of small numbers of particles is simulated and the size of the superpositions is calculated based on their ability to make precision measurements. Experimental creation of strongly correlated and NOON-type superpositions with about 100 atoms seems feasible in the near future.