Saturating interaction in coherently coupled two-component Bose-Einstein condensates
Phys. Rev. A 112, 063322 – Published 23 December, 2025
DOI: https://doi.org/10.1103/3pgn-3mqy
Abstract
Rabi-coupled spinor Bose-Einstein condensates, with competing intra- and interspecies interactions, enable independent control of two- and three-body interactions. We show that coupling can also drive the system into a strongly nonlinear regime of saturating interaction. More precisely, the equation of state interpolates between low- and high-density regimes described by two different two-body scattering lengths. Interestingly, the transition can be determined by the strength of the coupling. We experimentally demonstrate this saturation phenomenon by measurements of the expansion of a Bose-Einstein condensate as a function of the detuning and of the strength of the Rabi coupling in spin mixtures of potassium 39.
