# Three-body constrained bosons in double-well optical lattice

## TL;DR

This paper investigates the ground-state phases of three-body constrained bosons in a one-dimensional double-well optical lattice, revealing various quantum phases including Mott insulators, bond-order, and pair superfluidity.

## Contribution

It provides a detailed phase diagram for constrained bosons in a double-well lattice, highlighting novel gapped and gapless phases due to the geometry and interactions.

## Key findings

- Identification of Mott insulators and bond-order phases at commensurate densities.
- Discovery of a pair bond order phase resembling a valence-bond solid.
- Observation of a gapless pair superfluid phase at incommensurate densities.

## Abstract

We analyse the ground-state properties of three-body constrained bosons in a one dimensional optical lattice with staggered hoppings analogous to the double well optical lattice. By considering attractive and repulsive on-site interactions between the bosons, we obtain the phase diagram which exhibits various quantum phases. Due to the double-well geometry and three-body constraint several gapped phases such as the Mott insulators and dimer/bond-order phases emerge at commensurate densities in the repulsive interaction regime. Attractive interaction leads to the pair formation which leads to the pair bond order phase at unit filling which resembles the valence-bond solid phase of composite bosonic pairs. At incommensurate densities we see the signatures of the gapless pair superfluid phase.