Condensates induced by interband coupling in a double-well lattice

Understand

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.