A novel route to Bose-Einstein condensation of two-electron atoms

TL;DR

This paper introduces a new method for achieving Bose-Einstein condensation in two-electron atoms, specifically calcium-40, using optical pumping and forced evaporation, resulting in rapid condensation of thousands of atoms.

Contribution

It presents a novel cooling and trapping technique for two-electron atoms that bypasses the need for narrow intercombination line cooling.

Findings

Achieved Bose-Einstein condensation of 3000 calcium-40 atoms in under three seconds.

Enhanced phase space density by four orders of magnitude through optical pumping.

Optimized evaporation process minimized three-body losses during condensation.

Abstract

We present a novel route to Bose-Einstein condensation devised for two-electron atoms, which do not admit practicable cooling techniques based upon narrow intercombination lines. A dipole trap for $^{40}$Ca atoms in the singlet ground state is loaded from a moderately cold source of metastable triplet atoms via spatially and energetically selective optical pumping permitting four orders of magnitude increase of the phase space density. Further cooling to quantum degeneracy is achieved by forced evaporation optimized to minimize three-body losses. In a combined loading and evaporation cycle of less than three seconds we are able to condense 3000 atoms.