Controlled pairing symmetry of the superfluid state in systems of three-component repulsive fermionic atoms in optical lattices

TL;DR

This paper explores how the pairing symmetry of superfluid states in three-component fermionic atoms in optical lattices varies with interaction strengths, revealing transitions from extended s-wave to d-wave pairing driven by quantum fluctuations.

Contribution

It demonstrates the controllable change in pairing symmetry in three-component fermionic systems based on interaction anisotropy, linking it to underlying quantum fluctuation mechanisms.

Findings

Extended s-wave pairing when two interactions are strong

Transition to d-wave pairing as interactions become weaker

Change driven by competition among different quantum fluctuations

Abstract

We investigate the pairing symmetry of the superfluid state in repulsively interacting three-component (colors) fermionic atoms in optical lattices. When two of the three color-dependent repulsions are much larger than the other, pairing symmetry is an extended s wave, although the superfluid state appears adjacent to the paired Mott insulator in the phase diagram. As the difference between the three repulsions is decreased in square optical lattices, the extended s-wave pairing changes into a nodal s-wave pairing and then into a d-wave pairing. This change in pairing symmetry is attributed to the competition among the density fluctuations of unpaired atoms, the quantum fluctuations of the color-density wave, and those of the color-selective antiferromagnet. This phenomenon can be studied using existing experimental techniques.We investigate the pairing symmetry of the superfluid state in repulsively interacting three-component (color) fermionic atoms in optical lattices. When two of the three color-dependent repulsions are much stronger than the other, pairing symmetry is an extended $s$ wave although the superfluid state appears adjacent to the paired Mott insulator in the phase diagram. On the other hand, when two of the three color-dependent repulsions are weaker than the other, pairing symmetry is a d_{x^2-y^2}-wave. This change in pairing symmetry is attributed to the change in the dominant quantum fluctuations from the density fluctuations of unpaired atoms and the color-density wave fluctuations to the color-selective antiferromagnet fluctuations. This phenomenon can be studied using existing experimental techniques.