Scientists discover how to turn light into matter after 80-year quest 4 hours ago


This shows theories describing light and matter interactions. Credit: Oliver Pike, Imperial College London

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Imperial College London physicists have discovered how to create matter from light – a feat thought impossible when the idea was first theorised 80 years ago.

In just one day over several cups of coffee in a tiny office in Imperial’s Blackett Physics Laboratory, three physicists worked out a relatively simple way to physically prove a theory first devised by scientists Breit and Wheeler in 1934.

Breit and Wheeler suggested that it should be possible to turn light into matter by smashing together only two particles of light (photons), to create an electron and a positron – the simplest method of turning light into matter ever predicted. The calculation was found to be theoretically sound but Breit and Wheeler said that they never expected anybody to physically demonstrate their prediction. It has never been observed in the laboratory and past experiments to test it have required the addition of massive high-energy particles.
The new research, published in Nature Photonics, shows for the first time how Breit and Wheeler’s theory could be proven in practice. This ‘photon-photon collider’, which would convert light directly into matter using technology that is already available, would be a new type of high-energy physics experiment. This experiment would recreate a process that was important in the first 100 seconds of the universe and that is also seen in gamma ray bursts, which are the biggest explosions in the universe and one of physics’ greatest unsolved mysteries.

The scientists had been investigating unrelated problems in fusion energy when they realised what they were working on could be applied to the Breit-Wheeler theory. The breakthrough was achieved in collaboration with a fellow theoretical physicist from the Max Planck Institute for Nuclear Physics, who happened to be visiting Imperial.

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