At Swansea University since 2005, Professor Madsen is an experimental physicist who specializes in work on fundamental physics with antimatter. He is co-founder and group leader in the ALPHA collaboration that was the first group to trap antihydrogen and observe the first quantum transitions in it and is pursuing precision comparisons with hydrogen. He has been actively involved in antihydrogen research since 2001, playing a substantial role in the ATHENA team that first formed low energy antihydrogen in 2002. He has a research group at CERN. His group plays a leading role in the ALPHA experiment in both physics and hardware and software design, and led the effort to implement several key techniques leading to the first antihydrogen trapping. It has furthermore conceptualised, designed and built significant parts of the ALPHA apparatus. For this work he has been awarded a Royal Society Senior Leverhulme Fellowship in 2010, and the 2011 James Dawson award for Excellence in Plasma Physics Research.

Areas of Expertise

  • Antihydrogen
  • Atomic Physics
  • Laser Cooling
  • Plasma Physics
  • Fundamental Physics
  • Spectroscopy
  • Non-neutral plasmas


  1. et. al. Observation of the 1S–2S transition in trapped antihydrogen. Nature 541, 566-510.
  2. Antihydrogen studies in ALPHA. Journal of Physics: Conference Series 770, 012021
  3. & (Eds.). Trapped Charged Particles - A Graduate Textbook with Problems and Solutions. World Scientific.
  4. ANTIHYDROGEN PHYSICS. In Trapped Charged Particles. -298). World Scientific.
  5. et. al. An improved limit on the charge of antihydrogen from stochastic acceleration. Nature 529(7586), 373-376.

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  • PH-128 Quantative Methods in Physics

    Developing and practising mathematical and analytical skills for physicists.


  • A laser-ablated Beryllium Ion Source for Sympathetic Cooling of Positrons in the ALPHA Experiment (current)

    Student name:
    Other supervisor: Prof Dirk Van Der Werf
    Other supervisor: Prof Michael Charlton
  • 'Positron Accumulation and Laser Excitation of the Positronium Atom' (awarded 2013)

    Student name:
    Other supervisor: Prof Dirk Van Der Werf
  • Antihydrogen formation, dynamics and trapping (awarded 2011)

    Student name:
    Other supervisor: Prof Michael Charlton

Research Groups

  • Experimental Physics Research Group

    A major focus of our research is low-energy positron and positronium physics, with particular application to the creation of ultra-low energy antihydrogen. This work is a key element of the ALPHA experiment based at the Antiproton Decelerator (AD) at CERN.