Tommey, JDR;
(2025)
Geometric and Dynamic Phases in Rydberg State Interferometry.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Rydberg states of atoms or molecules are characterised by having a highly excited valence electron. This leads to many exaggerated prop- erties such as extended lifetimes and large susceptibilities to electro- magnetic fields. In Part I of this thesis we explore such properties, looking at the ultra-strong driving regime of the Rabi model with Rydberg states, observing coherent Rydberg atom and microwave field interactions. Under ultra-strong driving simpler models break down, so Floquet methods are used and show excellent experimental agreement. The results presented are of importance for applications in the detection and precise calibration of microwave fields and in fast quantum state preparation for quantum information processing. The appeal of Rydberg states with their unique properties has meant that there has been an increased focus for applications in quantum technologies such as for Rydberg state sensing. Part II of this the- sis develops a coherent approach to this by performing interferometry with Rydberg states of atoms. We demonstrate experiments that probe dynamic and geometric phases in a Ramsey-type interferometer using Rydberg states of helium. A first experiment involves inhomogeneous electric-field gradients. Forces are applied to create a half-loop Stern-Gerlach interferometer. These experiments replicate approaches seen with atom-chip interfer- ometers, resulting in coherent superpositions of spatially separated momentum states. The experiment demonstrated here used low-ℓ Rydberg states in order to overcome non-adiabatic losses seen in a previous experiment using circular Rydberg states. Dispersive effects fundamentally limited this approach. Future experiments aimed at overcoming this dispersion could allow for a full-loop interferometer that could be sensitive to inertial effects. This inspired an experiment where the phase due to the motional- Stark effect is measured in a Ramsey-type interferometer. The motional- Stark phase is closely related to the He-McKellar-Wilkens geometric phase, an electromagnetic dual of the Aharonov-Bohm phase. The motional-Stark effect couples the external and internal motion of the atom and under certain electro-magnetic potentials can lead to a non- dispersive phase. The use of the motional-Stark phase for interferom- etery presents some interesting future application including the imple- mentation of an atom diode, performing accelerometry with Rydberg states, and exploring topological effects in neutral atom systems.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Geometric and Dynamic Phases in Rydberg State Interferometry |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2025. Original content in this thesis is licensed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) Licence (https://creativecommons.org/licenses/by/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. |
| Keywords: | Rydberg atoms, interferometry |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10203697 |
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