D-wave bosonic pair in an optical lattice

TL;DR

This paper introduces a bosonic model where pairs with d-wave symmetry form via ring exchange interactions, leading to potential superfluid and density wave states, with realizations in fermionic systems and analysis via mean field and TEBD methods.

Contribution

It proposes a new bosonic system with d-wave pairing and density wave states, analyzed through mean field and TEBD, and suggests experimental realization in fermionic systems.

Findings

D-wave pairs can condense into a superfluid at low densities.

A d-wave density wave state emerges at specific fillings.

Quantum phase transitions between these states are characterized.

Abstract

We present a bosonic model, in which two bosons may form a bound pair with d-wave symmetry via the four-site ring exchange interaction. A d-wave pairing superfluid as well as a d-wave density wave (DDW) state, are proposed to be achievable in this system. This exotic bosonic system can be realized in the BEC zone of a two-dimensional attractive p-band spinless fermionic system. By the mean field approach, we find that at low densities, the d-wave pairs may condensate, leading to a d-wave bosonic paired superfluid. At some particular filling factors, a novel phase, d-wave density wave state, emerges. We study this DDW state and its corresponding quantum phase transition in a two-leg ladder by the time-evolving block decimation (TEBD) method.