Phase diagram of the Bose-Hubbard model on a ring-shaped lattice with tunable weak links

TL;DR

This study investigates the phase diagram of the 1D Bose-Hubbard model on a ring with tunable weak links, revealing a novel local Mott phase that could inform atomtronic device design.

Contribution

It introduces the concept of a local Mott phase in a ring-shaped lattice with weak links, expanding understanding of phase control in Bose-Hubbard systems.

Findings

Identification of a local Mott phase in the phase diagram.

Demonstration of tunable insulating and conducting phases.

Potential implications for atomtronic device engineering.

Abstract

Motivated by recent experiments on toroidal Bose-Einstein condensates in all-optical traps with tunable weak links, we study the one-dimensional Bose-Hubbard model on a ring-shaped lattice with a small region of weak hopping integrals using quantum Monte Carlo simulations. Besides the usual Mott insulating and superfluid phases, we find a phase which is compressible but non superfluid with a local Mott region. This `local Mott' phase extends in a large region of the phase diagram. These results suggest that the insulating and conducting phases can be tuned by a local parameter which may provide a new insight to the design of atomtronic devices.