Clock shift in high field magnetic resonance of atomic hydrogen.
We have measured electron spin resonance line shifts due to collisions in atomic hydrogen gas compressed to densities approximately 10(18) cm(-3) in a strong magnetic field (4.6 T). The shift in a doubly polarized gas is negligible, in contrast with a mixture of two hyperfine states. This difference is explained by properly including effects of quantum statistics in atomic collisions and magnetic dipolar effects. We report on the first direct measurement of the difference between the triplet and singlet s-wave scattering lengths a(t) - a(s) = 60(10) pm, which is in agreement with existing theories.
Wihuri Physical Laboratory, Department of Physics, University of Turku, 20014 Turku, Finland.
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J
Ahokas
J
J
Järvinen
G V
GV
Shlyapnikov
S
S
Vasiliev