Hannover 2016 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 55: Ultra-cold atoms, ions and BEC IV (with A)

Q 55.1: Talk

Thursday, March 3, 2016, 14:30–14:45, f303

Spectroscopy of Topological Defects in Coulomb Crystals — •Philip Kiefer¹, Jonathan Brox¹, Miriam Bujak¹, Isabelle Schmager¹, Haggai Landa², and Tobias Schaetz¹ — ¹Atom-, Molekül- und optische Physik, Physikalisches Institut, Universität Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg — ²LPTMS, Université Paris Sud, Orsay, France

We study structural defects (kinks) experimentally, which we form during two related phase-transitions in Coulomb crystals. A cloud of ²⁴Mg-Ions is freezed into a crystalline structure, consisting of several tens of ions in a linear radiofrequency trap [1]. We observe the formation of topological defects with a structural phase transition from a linear chain to a 2D-zig-zag configuration. Numerical simulations predict a strong anharmonicity of the kink’s internal mode of vibration [2].

We observe the defects’ experimental occurrence, lifetime and annihilation due to controlled motional excitation of the localized mode. We reveal evidence for the (gapped) localized mode and present first data of spectroscopy results. Furthermore, the formation of kink configurations and the transformation of kinks between different structures in dependence on the trapping parameters are investigated.

[1] M. Mielenz et al., Phys. Rev. Lett. 110, 133004 (2013)

[2] H. Landa et al., New J. Phys. 15, 093003 (2013)