Integrable model of bosons in a four-well ring with anisotropic tunneling

Abstract

We introduce an integrable, four-well ring model for bosons where the tunneling couplings between nearest-neighbour wells are not restricted to be equal. We show how the model may be derived through the quantum inverse scattering method from a solution of the Yang–Baxter equation, and in turn solved by algebraic Bethe ansatz means. The model admits multiple pseudovacuum states. Numerical evidence is provided to indicate that all pseudovacua are required to obtain a complete set of Bethe eigenstates. The model has the notable property that there is a class of eigenstates which admit a simple, closed-form energy expression.