Mechanical excitation of trapped ions coupled to a nanomechanical oscillator

Laser-cooled ions confined in radiofrequency traps count among the best controllable quantum
systems with applications in fields such as spectroscopy, ultracold chemistry and quantum tech-
nologies. They offer a variety of well-established techniques for the manipulation and readout of
their internal and external quantum states and exhibit excellent coherence properties. Nanome-
chanical oscillators are solid-state objects on the nanometer scale. Their small sizes make them
excellent candidates for the study of the interface between classical and quantum physics and the
cooling and manipulation of their motion on the single-phonon level has recently been achieved.
Nanomechanical oscillators are highly sensitive transducers, making them excellent sensors for
small forces with famous applications such as atomic force microscopy. The combination of
different types of physical systems into a single hybrid system has been of increasing interest
in recent years. The goal is to exploit the individual advantages of the constituents in order to
develop new applications and techniques that the individual systems alone could not provide.
Hybrid systems coupling trapped ions to a charged nanomechanical oscillator may offer novel
techniques for the bidirectional manipulation and readout of the quantum states of motion of
both constituents. The subsystems are coupled by the electrostatic interaction of their charges
and act as coupled harmonic oscillators. By resonantly driving the ions with driven vibrations
of the nanomechanical oscillator, strong coupling can be achieved and the motional state of the
ions can be manipulated. Here, we present the successful coupling of trapped 40Ca+ ions to a
charged Ag2Ga nanowire in an ion-nanowire hybrid system in the classical regime. We present
a theoretical description for the classical dynamics of the resonantly driven ion motion and
support the results with numerical simulations. We simulate and experimentally investigate
the static effects of the charged nanowire on the trapping potential. We present experimental
results for the resonant excitation of the ion motion with the mechanically driven nanowire and
show the effects on the coupling strength for the variation of different coupling parameters.