Hannover 2016 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 12: Ultra-cold atoms, ions and BEC (with A)
Q 12.21: Poster
Montag, 29. Februar 2016, 16:30–19:00, Empore Lichthof
Dynamics of nonlinear excitations of helically confined charges — •Alexandra Zampetaki1, Jan Stockhofe1, and Peter Schmelcher1,2 — 1Zentrum für Optische Quantentechnologien, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany — 2The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
The confinement of long-range interacting particles on a curved manifold can modify significantly their effective interactions. In the special case of identical charges trapped on a helical geometry the effective two-body potential acquires an extraordinary oscillatory form [1].
For a closed helical trap the corresponding system of charges was recently found to exhibit an unconventional deformation of the linear spectrum when tuning the helix radius [2]. Here we show that the same geometrical parameter can affect significantly also the dynamical behaviour of an initially broad excitation for long times. In particular, for small values of the radius, the excitation disperses into the whole crystal whereas within a specific narrow regime of larger radii the excitation self-focuses, assuming finally a localized form. Beyond this regime, the excitation defocuses and the dispersion gradually increases again. We analyze this geometrically controlled nonlinear behaviour using an effective discrete nonlinear Schrödinger model, which allows us among others to identify a number of breather-like excitations.
[1] P. Schmelcher, EPL 95 50005 (2011).
[2] A. V. Zampetaki, J. Stockhofe and P. Schmelcher, Phys. Rev. A 91, 023409 (2015).