New opportunites for interactions and control with ultracold lanthanides

Abstract

Lanthanide atoms have an unusual electron configuration, with a partially filled shell of f orbitals. This leads to a set of characteristic properties that enable enhanced control over ultracold atoms and their interactions: large numbers of optical transitions with widely varying wavelengths and transition strengths, anisotropic interaction properties between atoms and with light, and a large magnetic moment and spin space present in the ground state. These features in turn enable applications ranging from narrow-line laser cooling and spin manipulation to evaporative cooling through universal dipolar scattering, to the observation of a rotonic dispersion relation, self-bound liquid-like droplets stabilized by quantum fluctuations, and supersolid states. In this short review, we describe how the unusual level structure of lanthanide atoms leads to these key features, and provide a brief and necessarily partial overview of experimental progress in this rapidly developing field.

Mixtures of Dipolar Gases in Two Dimensions: A Quantum Monte Carlo Study

“…First experiments showing dipolar effects were carried out with Cr, with a magnetic moment µ = 6µ B [5]. In the last years, two more candidates have joined this class of materials, Dy [6] with µ = 10µ B and Er [7] with µ = 7µ B , significantly widening the possibilities for observing the two main features of these systems: anisotropy and slow-decaying twobody interactions [8]. The different interaction between side-by-side moments (repulsive) and head-to-tail ones (attractive) leads to the formation of self-bound liquid drops if the number of atoms is above a threshold known as critical atom number [9].…”

Mixtures of dipolar gases in two dimensions: a quantum Monte Carlo study

“…First experiments showing dipolar effects were carried out with Cr, with a magnetic moment µ = 6µ B [5]. In the last years, two more candidates have joined to this class of materials, Dy [6] with µ = 10µ B and Er [7] with µ = 7µ B , widening significantly the possibilities for observing the two main features of these systems: anisotropy and slow-decaying two-body interactions [8]. The different interaction between side-by-side moments (repulsive) and head-to-tail ones (attractive) leads to the formation of self-bound liquid drops if the number of atoms is above a threshold known as critical atom number [9].…”