Group Members.

Permanent Staff:

Dr. Will Bryan

Prof. Mike Charlton

Dr. Stefan Eriksson

Dr. Niels Madsen

Prof. Helmut Telle

Dr. Dirk-Peter van der Werf

Dr Saijun Wu

Postdoctoral Researchers:

Dr. Will Bertsche

Dr Aled Isaac

The research of the group focuses on: positron physics, in particular the properties of positronium and antihydrogen; neutrino mass measurements; the interaction between laser light and particles; and cold atoms and ions.

Recent research highlights:

• first trapping of antihydrogen atoms in the laboratory (MC, NM, DPvdW, SE, W Bertsche)
• pioneering study of antihydrogen formation dynamics in an octopolar magnetic minimum neutral atom trap (MC, NM, DPvdW, W Bertsche)
• discovery of suppression of ionization in low energy antiproton-molecular collisions (MC)
• creation of the first atoms of ultra-low energy antihydrogen in the laboratory (MC, NM, DPvdW).
• pioneering studies of the mechanisms and dynamics of antihydrogen formation when antiprotons are merged with a positron cloud in a high-field Penning trap (MC, NM, DPvdW).
• demonstration that quadrupolar fields strong enough to trap antihydrogen have field gradients which dramatically reduce survival times for charged plasmas, but that positron and antiproton plasmas can be held in a Penning trap with a superimposed octupolar trap for periods consistent with the mixing cycles for antihydrogen formation (MC, NM, DPvdW).
• a new method to manufacture antiprotonic hydrogen (or protonium) in vacuum via the controlled interaction of cold antiprotons with molecular hydrogen ions producing states with microsecond liftimes suitable for spectroscopy (MC,NM,DPvdW).
• implementation of a state-of-the-art laser Raman system for monitoring dynamic behaviour and isotopic composition of the gas mixtures injected into the tritium beta-deacy source used in the KATRIN experiment to measure the neutrinio rest mass (MC, RL, HT).
• first observation of transitory low-lying electron states in Ar and Kr during multi-electron tunnel ionisation by a circularly-polarised laser pulse, an exciting development in attosecond science opening up the possibility to create exotic materials (WB).
• direct study of laser-induced electron-ion recombination using a beam of excited Kr^+ ions, elucidating the mechanism for the production of attosecond pulses in the XUV spectral region (WB).
• investigation of vibrational and rotational wavepackets in small molecules and ions with a view to their use in quantum computation; in particular the quantum revival of a laser-driven vibrartional wavepacket in D_2^+ has been isolated from an incohenrent bath of room-temperature D_2 (WB).
• investigation of reaction dynamics and molecular quantum states in the gas phase, exemplfied by CaH/CaD and their ions (HT).
• creation and manipulation of dense positron plasmas and the development in Swansea of a new rapid-cycle positron accumulator interfaced to both a laser system (for positronium spectroscopy) and a high magnetic field apparatus (to study magnetised positronium states) (MC, CAI, NM, HT, DPvdW).
• development of micro-optics and microtraps suitable for single-atom detection (SE).
• world's first creation of a Bose-Einstein Condensate on a permanent magnet atom chip (SE).
• proof of principle that scalable optical microcavities with open access can be used as detectors with single-atom sensitivity, a first step towards building a quantum network of neutral atoms on a chip (SE).