Cold atom scattering

Courteille P, Freeland RS, Heinzen DJ, yan Abeelen PA, Verhaar BJ. (1998) Obseryation of a Feshbach Resonance in Cold Atom Scattering. Phys. Rev. Lett. 81 69-72. 

Larsson, K. E., U. Dahlborg, and D, Jovic Collective Atomic Motions in Liquid Aluminium studied by Cold Neutron Scattering. Wien, Int. Atom. Energy Agency 1964. 

Bohn, J.L., Molecular spin relaxation in cold atom-molecule scattering, Phys. Rev. A, 61, 040702, 2000. 

Generally, the cold atoms used in experiments have additional angular momenta (electron orbital and/or electron spin and/or nuclear spin), so that more than one scattering channel a can be involved in a collision. Each channel has a separated atom... 

Braaten, E. and Hammer, H.-W., Resonant dimer relaxation in cold atoms with a large scattering length, Phys. Rev. A, 75, 052710, 2007. 

The Feshbach effect is a two-channel problem that can be described in terms of the Breit-Wigner scattering [25,26], and various aspects of such problems have been discussed by Feshbach [27] andFano [28]. In cold atom physics the idea of Feshbach resonances was introduced in Ref. [29], and optically induced resonances have been analyzed in Refs. [30-33]. 

To set the stage for further dispositions, Jeremy Hutson describes in Chapter 1 (entitled Theory of Cold Atomic and Molecular Collisions ) the basic theory of atomic and molecular scattering at low temperatures. This chapter introduces the concepts of the cross-section, the rate coefficient, and the scattering length, and describes the main ingredients of quantum collision theory. It is shown that the... 

This also works for the case of elastic scattering of identical particles in identical quantum states K aa aa must be multiplied by a factor of 2 to get the rate of momentum transfer (k scatters to kg k) since two atoms scatter per collision event. Gao ° has also described the formal theory for collisions of cold atoms taking into account identical particle symmetry. 

Interactions between neighboring atoms shift and broaden the line. This can be described from a many-body picture as a result of the mean field energy shift, AEe = (Anh2aeyg/ m) rig, where ae,g is the s-wave scattering length of atoms in state e and g, m is the atomic mass, and ng is the density of g-state atoms. From the an atomic standpoint it is equal to a cold collision frequency shift which we... 

A mercury atom that was ionized by a weak electron beam was captured in a miniature Paul (radio frequency) trap that has internal dimensions of rQ s 466 pm and zQ s 330 pm. The rf trapping frequency was 21.07 MHz with a peak voltage amplitude of about 730 V. The ion was laser cooled by a few microwatts of cw laser radiation that was frequency tuned below the 6s Si -6p Pi electric dipole transition near 194 nm. When the Hg+ ion was cold and the 194 nm radiation had sufficient intensity to saturate the strongly allowed S-P transition, 2 x 10 photons/s were scattered. With our collection efficiency, this corresponded to an observed peak count rate of about 10 s-1 against a background of less than 50 s— -. 

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