arXiv subjects

Lucy Downes

Publications and source records attributed to Lucy Downes.

4 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↗

arXiv2023

Simultaneous multi-band radio-frequency detection using high-orbital-angular-momentum states in a Rydberg-atom receiver

We demonstrate simultaneous detection of radio-frequency (RF) fields ranging from the very high-frequency (VHF) band (128 MHz) to terahertz frequencies (0.61 THz) using a caesium Rydberg-atom receiver. The RF fields are concurrently applied to a series of atomic transitions involving states of increasing orbital angular momentum, where the energy separations become progressively smaller, allowing access to a very wide range of radio frequencies. We show that the optical response of the system in the presence of the RF fields can be reproduced theoretically using a simple Lindblad-master-equation approach. Furthermore, we demonstrate experimentally that a series of amplitude-modulated tones can be detected simultaneously using multiple carrier frequencies. This demonstration opens the way for RF communications across multiple bands simultaneously using a single optical receiver.

physics.atom-ph↗

arXiv2023

Simple Python tools for modelling few-level atom-light interactions

Understanding the interactions between atoms and light is at the heart of atomic physics. Being able to `experiment' with various system parameters, produce plots of the results and interpret these is very useful, especially for those new to the field. This tutorial aims to provide an introduction to the equations governing near-resonant atom-light interactions and present examples of setting up and solving these equations in Python. Emphasis is placed on clarity and understanding by showing code snippets alongside relevant equations, and as such it is suitable for those without an excellent working knowledge of Python or the underlying physics. Hopefully the methods presented here can form the foundations on which more complex models and simulations can be built. All functions presented here and example codes can be found on GitHub.

physics.atom-ph↗

arXiv2022

A practical guide to Terahertz imaging using thermal atomic vapour

This tutorial aims to provide details on the underlying principles and methodologies of atom-based terahertz imaging techniques. Terahertz imaging is a growing field of research which can provide complementary information to techniques using other regions of the electromagnetic spectrum. Unlike infrared, visible and ultraviolet radiation, terahertz passes through many everyday materials, such as plastics, cloth and card. Compared with images formed using lower frequencies, terahertz images have superior spatial resolution due to the shorter wavelength, while compared to x-rays and gamma rays, terahertz radiation is non-ionising and safe to use. The tutorial begins with the basic principles of terahertz to optical conversion in alkali atoms before discussing how to construct a model to predict the fluorescent spectra of the atoms, on which the imaging method depends. We discuss the practical aspects of constructing an imaging system, including the subsystem specifications. We then review the typical characteristics of the imaging system including spatial resolution, sensitivity andbandwidth. We conclude with a brief discussion of some potential applications

physics.atom-ph↗