Macroscopic two-state systems in trapped atomic condensates

TL;DR

This paper explores macroscopic two-state quantum systems in a Bose-Einstein condensate confined in a ring with a Josephson link, demonstrating superpositions, dynamics, and measurable coherence.

Contribution

It introduces a macroscopic two-state system based on BEC persistent currents, analyzing superpositions, dynamics, and noise effects in Josephson-ring geometries.

Findings

Macroscopic superpositions of BEC flows are energetically favorable.

Emergence of two-state dynamics in low energy limit.

Coherent dynamics are experimentally measurable.

Abstract

We consider a macroscopic two-sate system based on persistent current states of a Bose-Einstein condensate (BEC) of interacting neutral atoms confined in a ring with a weak Josephson link. We demonstrate that macroscopic superpositions of different BEC flows are energetically favorable in this system. Moreover, a macroscopic two-state dynamics emerges in the low energy limit. We also investigate fundamental limitations due to the noise inherent to the interacting BEC of Josephson-ring geometry. We show that the coherent macroscopic dynamics is readily measurable for an experimentally accessible range of parameters.