Estimating bounds on collisional relaxation rates of spin-polarized {sup 87}Rb atoms at ultracold temperatures
- National Inst. of Standards and Technology, Gaithersburg, MD (United States)
The recent observation of Bose-Einstein condensation (BEC) in magnetically trapped alkali atoms has brought to completion a 15 year attempt to achieve BEC in a weakly interacting atomic system. The success of BEC in both {sup 87}Rb and {sup 23}Na and evidence for BEC in {sup 7}Li were remarkable achievements brought about by the development of laser cooling during the past decade, the design of optical and magnetic traps for holding cold atomic samples, and most recently the development of evaporative cooling techniques to cool atoms below the recoil limit. The authors present quantum scattering calculations for the collisional relaxation rate coefficient of spin-polarized {sup 87}Rb(f = 2, m = 2) atoms, which determines the loss rate of cold Rb atoms from a magnetic trap. Unlike the lighter alkali atoms, spin-polarized {sup 87}Rb atoms can undergo dipolar relaxation due to both the normal spin-spin dipole interaction and a second-order spin-orbit interaction with distance electronic states of the dimer. The authors present ab initio calculations for the second-order spin-orbit terms for both Rb{sub 2} and Cs{sub 2}. The corrections lead to a reduction in the relaxation rate for {sup 87}Rb. The primary concern is to analyze the sensitivity of the {sup 87}Rb trap loss to the uncertainties in the ground state molecular potentials.
- Sponsoring Organization:
- Office of Naval Research, Washington, DC (United States)
- OSTI ID:
- 419643
- Journal Information:
- Journal of Research of the National Institute of Standards and Technology, Journal Name: Journal of Research of the National Institute of Standards and Technology Journal Issue: 4 Vol. 101; ISSN 1044-677X; ISSN JRITEF
- Country of Publication:
- United States
- Language:
- English
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