Hidden order in 1D Bose insulators

TL;DR

This paper uncovers a novel hidden order phase in 1D Bose insulators with long-range interactions, characterized by non-local string correlations, and predicts a distinctive spectral signature for experimental detection.

Contribution

It identifies a new hidden order phase between Mott and density wave insulators in 1D Bose systems with long-range interactions and develops a mean field theory to describe its excitations.

Findings

Discovery of a hidden order phase with string correlations

Prediction of a sharp resonance in the absorption spectrum

Development of a mean field theory for all insulating phases

Abstract

We investigate the phase diagram of spinless bosons with long range (~ 1/r^3) repulsive interactions, relevant to ultracold polarized atoms or molecules, using DMRG. Between the two conventional insulating phases, the Mott and density wave phases, we find a new phase possessing hidden order revealed by non local string correlations analogous to those characterizing the Haldane gapped phase of integer spin chains. We develop a mean field theory that describes the low energy excitations in all three insulating phases. This is used to calculate the absorption spectrum due to oscillatory lattice modulation. We predict a sharp resonance in the spectrum due to a collective excitation of the new phase that would provide clear evidence for the existence of this phase.