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Q: Fachverband Quantenoptik und Photonik

Q 53: Quantum information: Atoms and ions IV

Q 53.2: Talk

Thursday, March 21, 2013, 14:30–14:45, A 310

Trapping of Topological-Structural Defects in Coulomb Crystals — •Jonathan Brox¹, Haggai Landa², Manuel Mielenz¹, Benni Reznik², and Tobias Schaetz¹ — ¹Atom-, Molekül- und optische Physik, Physikalisches Institut, Universität Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg — ²School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel

We study experimentally and theoretically structural defects which are formed during the transition from a laser cooled cloud to a Coulomb crystal, consisting of tens of ions in a linear radiofrequency trap. We demonstrate the creation of predicted topological defects (‘kinks’) in purely two-dimensional crystals [1], and also find kinks which show novel dynamical features in a regime of parameters not considered before. The kinks are always observed at the centre of the trap, showing a large nonlinear localized excitation, and the probability of their occurrence surprisingly saturates at ∼ 0.5. Simulations reveal a strong anharmonicity of the kink’s internal mode of vibration, due to the kink’s extension into three dimensions. As a consequence, the periodic Peierls-Nabarro potential experienced by a discrete kink becomes a globally confining potential, capable of trapping one cooled defect at the center of the crystal.

[1] H. Landa et al., Phys. Rev. Lett. 104, 043004 (2010)