Quantum phases of hardcore bosons in two coupled chains: A density matrix renormalization group study

TL;DR

This study explores the quantum phases of hardcore bosons in two coupled chains using DMRG, revealing novel pair-superfluid and density wave phases induced by inter-chain interactions, with potential cold atom experimental realizations.

Contribution

It introduces the phase diagram of coupled hardcore bosons, identifying new phases like pair-superfluid and density wave of bound pairs, analyzed via DMRG.

Findings

Identification of superfluid, density wave, pair-superfluid, and bound pair density wave phases.

Demonstration of inter-chain pairing leading to novel quantum phases.

Discussion of experimental realization in cold dipolar gases.

Abstract

We consider hardcore bosons in two coupled chain of one dimensional lattices at half filling with repulsive intra-chain interaction and inter-chain attraction. This can be mapped on to a coupled chain of spin-1/2 XXZ model with inter chain ferromagnetic coupling. We investigate various phases of hardcore bosons (and related spin model) at zero temperature by density matrix renormalization group method. Apart from the usual superfluid and density wave phases, pairing of inter chain bosons leads to the formation of novel phases like pair-superfluid and density wave of strongly bound pairs. We discuss the possible experimental realization of such correlated phases in the context of cold dipolar gas.