Feasibility of ground-based shell-shaped BECs*

Many-body systems confined in shells have recently experienced a huge progress offered by ongoing experiments in orbital microgravity, which have already made crucial steps towards creating the first shell-shaped Bose-Einstein condensate (BEC) [1]. However, in principle there are two complementary methods for realization of such shells in ground-based laboratories: (i) a harmonically trapped dual-component mixture with equal trap frequencies combined with tunable inter-component interaction [2], and (ii) a single-component BEC in a bichromatic optical dipole trap where gravity is compensated by a magnetic field gradient.

To analyze both setups and understand whether stable shell-shaped BECs are feasible, we evaluate suitable atomic species, laser setups, and parameter thresholds which are required to create closed shells. The latter is especially important, as shell-shaped BECs tend to easily open up as soon as the system deviates from the ideal case.

[1] R. A. Carollo et al., arXiv:2108.05880 (2021).

[2] A. Wolf et al., arXiv:2110.15247 (2021).