Improved variational approach to the two-site Bose-Hubbard model

TL;DR

This paper introduces a refined variational method that effectively models the ground state of a biased two-site Bose-Hubbard system, capturing key quantum phenomena such as fragmentation and cat-like state formation.

Contribution

It presents a new, simple variational ansatz that accurately describes the ground state properties across various parameters of the model.

Findings

Accurately captures ground state properties of the model

Reproduces fragmentation phenomena before cat state formation

Describes formation of strongly correlated cat-like states

Abstract

An improved variational ansatz is proposed to capture the most striking properties of the ground state of a slightly biased attractive two-site Bose-Hubbard Hamiltonian. Our ansatz, albeit its simplicity, is found to capture well the exact properties of the ground state for a wide variety of model parameters, in particular the fragmentation occurring before the formation of cat-like states and also the formation of strongly correlated cat-like states.