It can be considered as counterintuitive that particles can be trapped by using alternating current (AC) fields. Despite the fact the applied potential oscillates between trapping and repelling, even interacting many-body systems can be stably trapped and cooled close to the quantum ground state. Ions in a Paul trap are a remarkable example, where unprecedented spectroscopic accuracy and the creation of large multiparticle entangled states suited for quantum information processing have been demonstrated, with nonlinear heating being very weak. The periodic modulation of potentials or applied laser forces is becoming an increasingly important tool also with ultracold atoms and molecules, and in recent years a new platform has emerged, with hybrid traps for ions and atoms.
In this seminar I will give an overview on trapped ions and their dynamics in Paul traps, and describe some recent experiments with hybrid traps. I will present earlier theoretical studies into the time-dependent nonlinear dynamics of ion crystals and how to treat their periodically driven modes using a ’Floquet-Lyapunov’ transformation [1,2], which have been verified to high accuracy in an experiment with a planar ion crystal [3]. I will also discuss some results from an ongoing work on the states of an atom quasi-bound to an ion which is periodically driven inside a Paul trap [4]. The time-dependent framework that we develop can be applied to general quantum scattering problems of particles subject to periodic fields.
[1] H. Landa, M. Drewsen, B. Reznik and A. Retzker, J. Phys. A : Math. Theor. 45, 455305 (2012).
[2] H. Landa, M. Drewsen, B. Reznik and A. Retzker, New J. Phys 14, 093023 (2012).
[3] H. Kaufman, S. Ulm, G. Jacob, U. Poschinger, H. Landa, A. Retzker, M. B. Plenio and F. Schmidt-Kaler, Phys. Rev. Lett. 109, 263003 (2012).
[4] H. Landa and G. Shlyapnikov, in preparation.