Anisotropy induced Feshbach resonances in a quantum dipolar gas of magnetic atoms

TL;DR

This study investigates the anisotropic Feshbach resonances in ultracold magnetic dysprosium atoms, revealing their dependence on magnetic dipole interactions and isotope variations through first-principles calculations.

Contribution

It provides the first detailed theoretical analysis of anisotropic Feshbach resonances in magnetic lanthanide atoms, highlighting their unique coupling mechanisms.

Findings

Approximately a dozen Feshbach resonances predicted within 20 mT magnetic field range

Resonance positions are highly sensitive to dysprosium isotope

Strong correlation between anisotropy and Feshbach spectrum

Abstract

We explore the anisotropic nature of Feshbach resonances in the collision between ultracold magnetic submerged-shell dysprosium atoms, which can only occur due to couplings to rotating bound states. This is in contrast to well-studied alkali-metal atom collisions, where most Feshbach resonances are hyperfine induced and due to rotation-less bound states. Our novel first-principle coupled-channel calculation of the collisions between open-4f-shell spin-polarized bosonic dysprosium reveals a striking correlation between the anisotropy due to magnetic dipole-dipole and electrostatic interactions and the Feshbach spectrum as a function of an external magnetic field. Over a 20 mT magnetic field range we predict about a dozen Feshbach resonances and show that the resonance locations are exquisitely sensitive to the dysprosium isotope.