Vortex macroscopic superpositions in ultracold bosons in a double-well potential

TL;DR

This paper investigates macroscopic superpositions of ultracold bosons in a double-well potential, revealing that transverse vortices tunnel faster than axisymmetric ones, enabling experimental observation of orbital superpositions.

Contribution

It introduces a simplified description of complex many-body vortex dynamics in ultracold bosons, highlighting the faster tunneling of transverse vortices and their potential for experimental detection.

Findings

Transverse vortices tunnel significantly faster than axisymmetric vortices.

Macroscopic superpositions are generated within realistic experimental times.

A small set of many-body states suffices to describe the complex dynamics.

Abstract

We study macroscopic superpositions in the orbital rather than the spatial degrees of freedom, in a three-dimensional double-well system. We show that the ensuing dynamics of $N$ interacting excited ultracold bosons, which in general requires at least eight single-particle modes and ${N+7 \choose N}$ Fock vectors, is described by a surprisingly small set of many-body states. An initial state with half the atoms in each well, and purposely excited in one of them, gives rise to the tunneling of axisymmetric and transverse vortex structures. We show that transverse vortices tunnel orders of magnitude faster than axisymmetric ones and are therefore more experimentally accessible. The tunneling process generates macroscopic superpositions only distinguishable by their orbital properties and within experimentally realistic times.