Rydberg State Engineering and Motional Interference with Trapped Ions

by Robin Frederick Thomm (Stockholm University)

Thursday 3 Sept 2026, 10:00 → 13:00 Europe/Stockholm

FB53 (AlbaNova Main Building)

Abstract
Trapped ions are one of the leading platforms for quantum technologies due to their excellent control over their internal
electronic and external motional degrees of freedom. Many techniques and interesting effects rely on the coupling of the
ions to their motion, which makes precise control of them paramount.
In this work, two novel techniques for motional state detection are presented. They allow the probing of certain motional
states with a single measurement, without affecting the motion of the measured ion. These techniques are employed to
generate and detect a highly entangled state between two motional modes in a novel manner. Furthermore, we harness the
rich and intricate dynamics arising from the coupling of the ion's motion to its electronic degrees of freedom to study the
emergence of interference. Theoretical predictions, describing interference both in the quantum and the classical regimes,
are verified, offering a new and more intuitive description of interference, not just for trapped ions, but for a variety of
systems that can be described in a similar way.
On the other hand, Rydberg excitation with trapped ions enables new interaction mechanisms and makes them extremely
sensitive to their surroundings. This thesis presents advances towards Rydberg experiments with longer ion strings and
concludes with a first demonstration of coherent population transfer between Rydberg states in trapped ions. The methods
developed significantly increase the toolbox for trapped Rydberg ions, enabling more sophisticated experiments, especially
when multiple different Rydberg states are involved, and allow more flexibility when using longer ion strings.