Heidelberg 2015 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 23: Ultra-cold atoms, ions and BEC IV (with Q)

A 23.7: Vortrag

Mittwoch, 25. März 2015, 16:00–16:15, C/HSW

Two-channel model of Penning ionization of cold metastable neon atoms — •Christian Cop and Reinhold Walser — Institut für Angewandte Physik, Technische Universität Darmstadt, Hochschulstr. 4a, 64289 Darmstadt

At present, many experiments are geared towards Bose-Einstein-Condensation of other elements besides the alkalies; rare-earth-gases, composite molecules and metastable noble gases. At the Technical University of Darmstadt, the group of G. Birkl investigates experimentally the prospects to condense metastable neon atoms (Ne*) [1]. The high internal energy of Ne* (∼16eV) leads to loss rates through Penning ionization (PI). Spin-polarized samples are expected to have lower loss rates than unpolarized samples since PI is forbidden here. For Ne*, suppression of PI has been observed. Interestingly, the bosonic isotopes 20Ne* and 22Ne* behave very differently; suppression ratios deviate by one order of magnitude and scattering lengths differ in sign.

To explain these differences we set up a two-channel model. The colliding Ne* atoms are subject to quantum-statistical effects which we include by adapting already existing single-channel models [2]. We present our results and show that they are in good agreement with the measurements.

[1] G. Birkl et al., Cold and trapped metastable noble gases, Rev. Mod. Phys., 84, 175-210 (2012).

[2] C. Orzel et al., Spin polarization and quantum-statistical effects in ultracold ionizing collisions, Phys. Rev. A, 59, 1926 (1998).

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