Ultracold collisions in metastable helium

G Peach,D G Cocks,I B Whittingham

doi:10.1088/1742-6596/810/1/012003

G Peach, D G Cocks + Show 1 more

Open Access

https://doi.org/10.1088/1742-6596/810/1/012003

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Abstract

Photoassociation processes are studied in ultracold collisions between different isotopes of metastable He(23S) and He(23P) atoms; Penning and associative ionization rates for collisions between two He(23S) atoms are also obtained. Comparisons are made with data from existing experiments.

Highlights

Bose-Einstein condensation (BEC) was first observed in alkali atoms in 1995 and a little later in atomic hydrogen
Ultracold collisions of metastable helium atoms are widely used to study collision dynamics in dilute quantum gases as the large internal energy can be released during collisions, allowing novel experimental strategies based upon single atom detection to be implemented
Photoassociation of ultracold atoms provides a powerful technique for the study of ultracold collisions in which two interacting cold atoms are resonantly excited by a laser to bound states of the associated molecule

Summary

Introduction

Bose-Einstein condensation (BEC) was first observed in alkali atoms in 1995 and a little later in atomic hydrogen. The resulting spectra have a very high resolution of < 1 MHz. Currently we are investigating elastic and ionizing collisions in spin-polarized metastable helium in the absence of an exciting laser, where the spin-dipole interaction can induce relaxation from the initial spin-polarized state to states from which Penning and associative ionization is highly probable. Scattering processes In the absence of an exciting laser, ionizing collisions in spin-polarized metastable helium can still take place because the spin-dipole interaction can induce relaxation from the initial spinpolarized state to spin states of [He(23S1) + He(23S1)] from which Penning and associative ionization is highly probable. The third column lists the levels after a 1% variation is applied to the short-range potentials

Results

Scattering processes

Conclusions