title: Anisotropic hyperfine interactions limit the efficiency of spin-exchange optical pumping of ³He nuclei.
abstract: We use accurate ab initio and quantum scattering calculations to demonstrate that the maximum ³He spin polarization that can be achieved in spin-exchange collisions with potassium (³⁹K) and silver (¹⁰⁷Ag) atoms is limited by the anisotropic hyperfine interaction. We find that spin exchange in Ag-He collisions occurs much faster than in K-He collisions over a wide range of temperatures (10-600 K). Our analysis indicates that measurements of trap loss rates of ²S atoms in the presence of cold ³He gas may be used to probe anisotropic spin-dependent interactions in atom-He collisions.
authors.affiliation: Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138, USA. tshcherb@cfa.harvard.edu
authors.forename: T V
authors.initials: TV
authors.lastname: Tscherbul
authors.forename: P
authors.initials: P
authors.lastname: Zhang
authors.forename: H R
authors.initials: HR
authors.lastname: Sadeghpour
authors.forename: A
authors.initials: A
authors.lastname: Dalgarno