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Alexandra Tofful

Alexandra Tofful

Higher scientist

Alexandra is an experimental physicist in the Optical Frequency Metrology group within the Time and Frequency department.

She first joined NPL as a PhD student in 2019 working on the ytterbium ion optical clock. After receiving her PhD in early 2023, she continued working on the same project. Alexandra focuses on the continuous improvement of the ytterbium ion optical clock, both in terms of performance and the level of automation of the experiment and data analysis, reducing the required manual intervention and aiming towards unattended clock operation.

Alexandra has actively participated in several international optical clock comparison campaigns since 2019. In particular, she had a leading role in the optimisation and operation of the ytterbium ion optical clock for the 2022 and 2023 comparison campaigns, in the measurement and analysis of the systematic frequency shifts, and in the evaluation of the absolute frequency of the optical clock via International Atomic Time.

Alexandra graduated with a BSc in Physics from King’s College London in 2018, and then proceeded to join the CDT in Controlled Quantum Dynamics at Imperial College London, which expanded her background in atomic physics and quantum technologies. After receiving an MRes, she moved on to the PhD which was based full time at NPL.

Areas of interest

  • Improving the performance of the ytterbium ion optical clock
  • Clock comparison campaigns for international optical frequency metrology
  • Creating a robust optical clock system with the goal of unattended operation using the ARTIQ framework
  • Writing modular and practical code for data analysis, experimental control, and automation
  • Using optical clocks to try and detect oscillations and transient variations in the fine structure constant.

Key publications

  • Advances in performance and automation of a single ytterbium ion optical clock
    Alexandra Tofful, PhD Thesis, Imperial College London (2023)
  • Analysis of atomic-clock data to constrain variations of fundamental constants
    N. Sherrill, A. O. Parsons, C. F. A. Baynham, W. Bowden, E. A. Curtis, R. Hendricks, I. R. Hill, R. Hobson, H. S. Margolis, B. I. Robertson, M. Schioppo, K. Szymaniec, A. Tofful, J. Tunesi, R. M. Godun and X. Calmet
    New J. Phys. 25 093012 (2023)
  • Measuring the stability of fundamental constants with a network of clocks
    G. Barontini, L. Blackburn, V. Boyer, F. Butuc-Mayer, X. Calmet, J. R. Crespo López-Urrutia, E. A. Curtis, B. Darquié, J. Dunningham, N. J. Fitch, E. M. Forgan, K. Georgiou, P. Gill, R. M. Godun, J. Goldwin, V. Guarrera, A. C. Harwood, I. R. Hill, R. J. Hendricks, M. Jeong, M. Y. H. Johnson, M. Keller, L. P. Kozhiparambil Sajith, F. Kuipers, H. S. Margolis, C. Mayo, P. Newman, A. O. Parsons, L. Prokhorov, B. I. Robertson, J. Rodewald, M. S. Safronova, B. E. Sauer, M. Schioppo, N. Sherrill, Y. V. Stadnik, K. Szymaniec, M. R. Tarbutt, R. C. Thompson, A. Tofful, J. Tunesi, A. Vecchio, Y. Wang and S. Worm
    EPJ Quantum Technology 9, 12 (2022)

E-mail Alexandra Tofful