arXiv subjects

Karen Wadenpfuhl

Publications and source records attributed to Karen Wadenpfuhl.

3 recordsLinked to original sources

arXiv2026

Switching Rydberg interactions by three orders of magnitude using a terahertz field

Atom-based quantum computing exploits the ability to enhance atom-atom interactions by employing laser excitation to higher-excited Rydberg states. Additional fields that drive transitions between Rydberg states can offer independent control of these atom-atom interactions. However, as microwave (mw) fields only provide access to states with similar principal quantum number $n$, their ability to switch the interactions' strength is limited. Here, we use a pulsed terahertz field to rapidly switch the strength of interactions between Rydberg atoms by three orders of magnitude. We demonstrate interaction switching using photon storage, where the terahertz field induces an interaction induced dephasing of the stored photon. This ability to switch interactions offers advantages for single-qubit readout, state-detection schemes, quantum annealing, and Rydberg quantum optics.

physics.atom-ph↗

arXiv2025

Unravelling the Structures in the van der Waals Interactions of Alkali Rydberg Atoms

Rydberg atoms are used in a wide range of applications due to their peculiar properties like strong dipolar and van der Waals interactions. The choice of Rydberg state has a huge impact on the strength and angular dependence of the interactions, and so a detailed understanding of the underlying processes and resulting properties of the interactions is therefore key to select the most suitable states for experiments. We study the van der Waals interactions in alkali-metal atoms in detail and highlight the structures which allow an understanding and exploitation of the various interaction properties. A particular theme is the identification of Förster resonances with $n_1 \neq n_2$, which offer interaction potentials with a wide range of properties that make them particularly interesting for experimental applications. A second theme is a focus on the underlying structures that shape the angular dependency and sign of the interactions. This understanding - instead of brute-force calculations - allows for a much simpler and more systematic search for suitable pair states. These insights can be used for the selection of tailored interaction potentials subject to experimental constraints and requirements. We use rubidium as an example species in this work and also provide data for cesium and pair states that are coupled via two- or three-photon transitions, i.e. up to $F$ states, in the Appendix.

physics.atom-ph↗

arXiv2025

Emergence of synchronisation in a driven-dissipative hot Rydberg vapor

We observe synchronisation in a thermal (35-60 °C) atomic (Rb) ensemble driven to a highly-excited Rydberg state (principle quantum number n ranging from 43 to 79). Synchronisation in this system is unexpected due to the atomic motion, however, we show theoretically that sufficiently strong interactions via a global Rydberg density mean field causes frequency and phase entrainment. The emergent oscillations in the vapor's bulk quantities are detected in the transmission of the probe laser for a two-photon excitation scheme.

physics.atom-ph↗