Quantum Phase Transitions and the Hidden Order in a Two-Chain Extended Boson Hubbard Model at Half-Odd-Integer Fillings

TL;DR

This paper explores the complex phase diagram of two coupled dipolar boson chains at half-odd-integer fillings, revealing four distinct phases and a hidden string order parameter akin to that in integer-filling Mott insulators.

Contribution

It introduces a detailed analysis of phase transitions and hidden order in a two-chain extended boson Hubbard model at half-odd-integer fillings.

Findings

Identification of four phases: Mott insulators, resonant superfluid, paired superfluid, and density waves.

Discovery of a hidden string order parameter in the Mott insulating phase.

Demonstration of rich phase behavior in coupled dipolar boson chains.

Abstract

We study the phase diagram of two weakly coupled one-dimensional dipolar boson chains at half-odd-integer fillings. We find that the system contains a rich phase diagram. Four different phases are found. They are the Mott insulators, the single-particle resonant superfluid, the paired superfluid, and the bond- or inter-chain density waves. Moreover, the Mott insulating phase can be further classified according to a hidden string order parameter, which is analogous to the one investigated recently in the one-dimensional boson Mott insulator at integer fillings.