Superfluid transition of a strongly ferromagnetic Bose gas

The recently-realized ⁷Li condensate [1] is the first strongly ferromagnetic BEC available in a laboratory. Contrary to the both mean-field picture and an earlier claim of split transitions [2], we theoretically show that, in three spatial dimensions, such a strongly ferromagnetic gas must undergo a first order transition from the normal phase directly into a state with finite condensate density and magnetization. We will discuss the experimental signatures for the first order transition in a trapped gas, and the role of magnetic field and spin imbalance [3]. We will also report on the magnetism of the strongly ferromagnetic Bose gas in quasi-2D confinement.

[1] Huh, Kim, Kwon, Choi, Physical Review Research 2, 033471 (2020)

[2] Natu, Mueller, Physical Review A 84, 053625 (2011)

[3] How, Yip, arxiv:2401.12541