Physics and Astronomy
Proceedings of the National Academy of Sciences
We observed and controlled the Brownian motion of solitons. We launched solitonic excitations in highly elongated 87 Rb Bose-Einstein condensates (BECs) and showed that a dilute background of impurity atoms in a different internal state dramatically affects the soliton. With no impurities and in one-dimension (1D), these solitons would have an infinite lifetime, a consequence of integrability. In our experiment, the added impurities scatter off the much larger soliton, contributing to its Brownian motion and decreasing its lifetime. We describe the soliton's diffusive behavior using a quasi-1D scattering theory of impurity atoms interacting with a soliton, giving diffusion coefficients consistent with experiment.
soliton, Brownian motion, Bose-Einstein condensate, diffusion, fluctuation, dissipation
Lauren M. Aycock, Hilary M. Hurst, Dimitry K. Efimkin, Dina Genkina, Hsin-I Lu, Victor M. Galitski, and I. B. Spielman. "Brownian motion of solitons in a Bose-Einstein Condensate" Proceedings of the National Academy of Sciences (2017). https://doi.org/10.1073/pnas.1615004114