# Bose-Einstein condensation of erbium atoms in a quasielectrostatic optical dipole trap

## TL;DR

This paper demonstrates the creation of a Bose-Einstein condensate of erbium atoms using a quasielectrostatic optical dipole trap generated by a midinfrared CO2 laser, highlighting a novel trapping and cooling method for rare-earth quantum gases.

## Contribution

It reports the first realization of erbium BEC in a quasielectrostatic optical dipole trap using a midinfrared laser, combining narrow-line cooling and evaporative cooling with magnetic field assistance.

## Key findings

- Produced spin-polarized erbium BEC with 30,000 atoms.
- Successfully loaded the dipole trap from a narrow-line magneto-optic trap.
- Achieved evaporative cooling in a quasistatic optical trap.

## Abstract

Quantum gases of rare-earth elements are of interest due to the large magnetic moment of many of those elements, leading to strong dipole-dipole interactions, as well as an often nonvanishing orbital angular momentum in the electronic ground state, with prospects for long coherence time Raman manipulation, and state-dependent lattice potentials. We report on the realization of a Bose-Einstein condensate of erbium atoms in a quasielectrostatic optical dipole trap generated by a tightly focused midinfrared optical beam derived from a $\textrm{CO}_2$ laser near 10.6$\mu$m in wavelength. The quasistatic dipole trap is loaded from a magneto-optic trap operating on a narrow-line erbium laser cooling transition near 583nm in wavelength. Evaporative cooling within the dipole trap takes place in the presence of a magnetic field gradient to enhance the evaporative speed, and we produce spin-polarized erbium Bose-Einstein condensates with $3\times10^4$ atoms.