Frequency shifts due to ultra-cold atom collisions

Journal Article · Wed Dec 01 04:00:00 EST 1993 · Bulletin of the American Physical Society

OSTI ID:67863

Gibble, K ^[1]

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1. Yale Univ., New Haven, CT (United States)

It was anticipated that laser cooling of atoms to 2 {mu}K would improve the accuracy and resolution of laser and microwave spectroscopies by 2 to 3 orders of magnitude. In state-of-the-art room temperature Cs frequency standards, the 9 GHz ground state hyperfine transition is measured with a fractional accuracy of 3 x 10{sup {minus}14}. Since all of the formerly known systematic effects that limit the accuracy increase either linearly or as some high power of the atom`s velocity, the accuracy of a laser cooled Cs standard should be {approx} 10{sup {minus}16}. However, at {mu}K temperatures, the de Broglie wavelengths of the atoms are much larger than the scale of the interatomic potential so that collision cross sections can be as large as {lambda}{sub dB}{sup 2}/2{pi} {approx} 10{sup {minus}10} cm{sup 2}. Here, collisional frequency shifts in a laser-cooled Cs fountain are measured to be {minus}1.4 x 10{sup {minus}12} corresponding to a cross section of 0.5 x 10{sup {minus}10} cm{sup 2}. The author also expects to report experimental results showing a potentially strong magnetic field dependence of these cross sections for fields smaller than 0.2 G. The field of ultra-cold collisions will also be reviewed.

• OSTI ID: 67863
• Report Number(s): CONF-9310400--
• Journal Information: Bulletin of the American Physical Society, Journal Name: Bulletin of the American Physical Society Journal Issue: 13 Vol. 38; ISSN BAPSA6; ISSN 0003-0503
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ATOM COLLISIONS
CESIUM
COOLING
MILLI EV RANGE
SPECTRAL SHIFT