Levitodynamics with charged nanoparticles in ion traps: trapping, cooling and multi-particle interaction
Lorenzo Dania1, Katharina Heidegger1, Dmitry S. Bykov1, Florian Goschin1, Maximilian Meusburger1, Giovanni Cerchiari1, Gabriel Araneda2, and Tracy E. Northup1
1) Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria
2) Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, U.K.
Nano and micro particles levitated in electrical, optical and magnetic traps are emerging as an exciting experimental platform with which to engineer macroscopic quantum states of motion and to probe ultra-small forces. Levitation offers an unprecedented level of thermal and mechanical isolation from the environment, which result in low damping of the center of mass motion and mechanical oscillations with ultra-high quality factors.
Our experiment is based on charged silica nanoparticles levitated in an ion trap in ultra-high vacuum (UHV). Here we give an overview of our experimental capabilities for trapping, cooling and for establishing multi-particle interactions:
First, we demonstrate a UHV-compatible loading technique with which we can load particles in a trap at pressures ranging from 1e-2 mbar down to 1e-11 mbar. This loading technique also provides a path for experiments with optically trapped particles in UHV at room temperature.
Next, we demonstrate a novel optical position-detection technique that is based on self-homodyne interference between the light scattered by a single nanoparticle and that of its mirror image. We demonstrate that measurement-based feedback cooling with the self-homodyne method outperforms feedback cooling based on other state-of-the-art detection techniques, paving the way to ground state preparation by feedback cooling in ion traps.
Finally, we show that deep ion trap potentials with large volumes are suitable for confining and strongly coupling two nanoparticles. We use this system to demonstrate three-dimensional sympathetic cooling of the center-of-mass motion of a silica nanoparticle, and we investigate the limits of this cooling technique.