PhD Student Position in Physics/Nanoscience

Cold ions in traps are among the best controlled quantum systems and have been employed with great success in quantum information, quantum simulation and chemistry. Through their tight confinement in a radiofrequency (RF) ion trap, the quantised states of their motion can be addressed and manipulated using laser fields. Many research groups are busy building experiments involving a mechanical oscillator coupled to another microscopic quantum system, such as neutral atoms, solid-state spin qubits, or superconducting devices. In these systems, the motion of the mechanical resonator can act as a sensitive probe for static and dynamic properties of the microscopic quantum system. At the same time, coupling the resonator to a controllable quantum system provides a way to prepare and detect non-classical states of mechanical motion.

In a project funded by the Swiss Nanoscience Institute (SNI,, we develop an experimental setup in which a laser-cooled trapped Ca+ ion is coupled to a charged Ag2Ga nanowire (see figure). We found through theoretical modelling that the nanowire can be used for the preparation of unusual quantum states of the ion motion in the trap, including very large coherent states, cat states and more complex quantum states which are difficult (if not impossible in some cases) to engineer with conventional optical means. The nanowire, by contrast, provides a ready and direct way to engineer and explore these unusual quantum states of ion motion.

The project is laid out as a collaboration between the groups of Prof. Stefan Willitsch ( and Prof. Martino Poggio ( at the University of Basel (Switzerland) combining their complementary expertise in cold ions and nanooscillators, respectively.

Aims and objectives of the project: The aim of the present project is explore the quantum dynamics and engineering of quantum states of an ultracold ion under the action of a nanomechanical resonator. In the course of the project, we will realise the following objectives: • Preparation and ground-state cooling of a trapped Ca+ ion in the quantum regime and its interfacing with a charged nanomechanical oscillator. • Studying the interaction of the ion with the nanowire in the quantum regime • Deterministic preparation of quantum states of the ion motion by tailoring coupling strengths and dynamics of the nanowire

Outcome of the project: The present proposal will establish a new type of quantum interface between the mechanical degrees of freedom of a single atom and a solid-state device and explore new ways to engineer complex quantum states of trapped atomic systems. This project stands right at the interface between quantum science, quantum optics and nanoscience and will introduce nano-techniques into quantum optics in a new and original fashion. We expect that the results of our work will form the basis of new research directions in the realm of atom/solid-state interfaces with applications in quantum technology, mass spectrometry and future directions in nanoscience.

Applicants should have a master degree in physics, nanoscience or physical chemistry. Applications should include a letter of motivation, a CV, transcripts of academic degrees and mark sheets and the contact details of at least two referees.

For further information, please contact Prof. Stefan Willitsch ( or Prof. Martino Poggio (