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arXiv · 2308.16069

Spin Rotations in a Bose-Einstein Condensate Driven by Counterflow and Spin-independent Interactions

David C. Spierings·Joseph H. Thywissen·Aephraim M. Steinberg
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Abstract

We observe spin rotations caused by atomic collisions in a non-equilibrium Bose-condensed gas of $^{87}$Rb. Reflection from a pseudomagnetic barrier creates counterflow in which forward- and backward-propagating matter waves have partly transverse spin directions. Even though inter-atomic interaction strengths are state-independent, the indistinguishability of parallel spins leads to spin dynamics. A local magnetodynamic model, which captures the salient features of the observed spin textures, highlights an essential connection between four-wave mixing and collisional spin rotation. The observed phenomenon has previously been thought to exist only in nondegenerate gases; our observations and model clarify the nature of these effective-magnetic spin rotations.

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David C. Spierings, Joseph H. Thywissen, Aephraim M. Steinberg. 2023-08-30. Spin Rotations in a Bose-Einstein Condensate Driven by Counterflow and Spin-independent Interactions. https://doi.org/10.1103/physrevlett.132.173401

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