Quantum correlations of few dipolar bosons in a double-well trap

TL;DR

This paper analytically investigates quantum correlations in a few dipolar bosons within a double-well trap, revealing how correlated hopping influences ground state structure and the formation of Schrödinger-cat states.

Contribution

It introduces an extended Bose-Hubbard model including correlated hopping and analyzes its effects on ground states and quantum correlations for few-particle systems.

Findings

Correlated hopping enables Schrödinger-cat states without strong onsite attraction.

Strong onsite attraction combined with large correlated hopping destroys cat states.

Ground state structure depends critically on correlated hopping parameter.

Abstract

We consider $N$ interacting dipolar bosonic atoms at zero temperature in a double-well potential. This system is described by the two-space-mode extended Bose-Hubbard (EBH) Hamiltonian which includes (in addition to the familiar BH terms) the nearest-neighbor interaction, correlated hopping and bosonic-pair hopping. For systems with $N=2$ and $N=3$ particles we calculate analytically both the ground state and the Fisher information, the coherence visibility, and the entanglement entropy that characterize the correlations of the lowest energy state. The structure of the ground state crucially depends on the correlated hopping $K_c$. On one hand we find that this process makes possible the occurrence of Schr\"odinger-cat states even if the onsite interatomic attraction is not strong enough to guarantee the formation of such states. On the other hand, in the presence of a strong onsite attraction, sufficiently large values of $|K_c|$ destroys the cat-like state in favor of a delocalized atomic coherent state.