Condensates induced by interband coupling in a double-well lattice

TL;DR

This paper predicts new inter-band phenomena in bosons within a double-well lattice, including enhanced Mott regions and various condensate types due to interaction-induced coupling between bands, which are experimentally observable.

Contribution

It introduces the concept of interaction-induced inter-band coupling leading to novel condensates and altered Mott regions in double-well optical lattices.

Findings

Larger Mott regions at even fillings due to inter-band coupling.

Multiple types of condensates including mixed and pair condensates.

Predicted phenomena are experimentally observable in current setups.

Abstract

We predict novel inter-band physics for bosons in a double-well lattice. An intrinsic coupling between the s and px band due to interaction gives rise to larger Mott regions on the phase diagram at even fillings than the ones at odd fillings. On the other hand, the ground state can form various types of condensates, including a mixture of single-particle condensates of both bands, a mixture of a single-particle condensate of one band and a pair-condensate of the other band, and a pair-condensate composed of one particle from one band and one hole from the other band. The predicted phenomena should be observable in current experiments on double-well optical lattices.