Non-Gaussian quantum correlations from a four-well Bose–Hubbard system

Abstract

We propose and analyse a four-well Bose–Hubbard model in a star configuration, with pumping in the middle well and damping at the three end wells. We find that the system can operate in a stationary regime and exhibits non-Gaussian quantum correlations. Bipartite and tripartite quantum correlations can be established between the end wells of the system which can be measured either in situ or in the outcoupled beams. Symmetric EPR steering can be achieved between the end wells at steady state. While in some cases, there exists asymmetric EPR steering between the middle well and one of the end wells during the transients, although it tends to be symmetric at steady state. The results show that quantum correlations depend deeply on the choice of collisional nonlinearity and the intensity of pumping. Different from the optical cavity, where dissipation is inevitable, our scheme allows for selective addition of pumping and damping. This feature makes it a flexible and controllable resource for experimental investigations and future technological applications.