Entanglement entropy and macroscopic quantum states with dipolar bosons in a triple-well potential

TL;DR

This paper investigates the ground state properties and entanglement characteristics of dipolar bosons in a triple-well potential, revealing transitions from delocalized to localized states and the emergence of macroscopic superpositions.

Contribution

It introduces a combined numerical and analytical analysis of the ground state, highlighting the transition from coherent to cat-like states in a triple-well dipolar boson system.

Findings

Maximum entanglement entropy at transition point

Identification of macroscopic cat-like states

Energy landscape with near-degenerate minima

Abstract

We study interacting dipolar atomic bosons in a triple-well potential within a ring geometry. This system is shown to be equivalent to a three-site Bose-Hubbard model. We analyze the ground state of dipolar bosons by varying the effective on-site interaction. This analysis is performed both numerically and analytically by using suitable coherent-state representations of the ground state. The latter exhibits a variety of forms ranging from the su(3) coherent state in the delocalization regime to a macroscopic cat-like state with fully localized populations, passing for a coexistence regime where the ground state displays a mixed character. We characterize the quantum correlations of the ground state from the bi-partition perspective. We calculate both numerically and analytically (within the previous coherent-state representation) the single-site entanglement entropy which, among various interesting properties, exhibits a maximum value in correspondence to the transition from the cat-like to the coexistence regime. In the latter case, we show that the ground-state mixed form corresponds, semiclassically, to an energy exhibiting two almost-degenerate minima.