London (ISJ) - British physicists demonstrated how to create matter from light ? a feat considered to be impossible when it was first conceived 80 years ago. Three physicists from Imperial College London worked out a relatively simple way to physically prove a theory first devised by scientists Breit and Wheeler in 1934, known as Breit-Wheeler process.
Breit and Wheeler suggested 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, they never expected anybody to physically demonstrate their prediction.
The new research, published in Nature Photonics, shows for the first time how Breit and Wheeler?s theory could be proven in practice. The ?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.
?Despite all physicists accepting the theory to be true, when Breit and Wheeler first proposed the theory, they said that they never expected it be shown in the laboratory. Today, nearly 80 years later, we prove them wrong. What was so surprising to us was the discovery of how we can create matter directly from light using the technology that we have today in the UK. As we are theorists we are now talking to others who can use our ideas to undertake this landmark experiment,? said Professor Steve Rose from the Department of Physics at the Imperial College London.
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.
The collider experiment that the scientists have proposed involves two key steps. First, the scientists would use an extremely powerful high-intensity laser to speed up electrons to just below the speed of light. They would then fire these electrons into a slab of gold to create a beam of photons a billion times more energetic than visible light.
The next stage of the experiment involves a tiny gold can called a hohlraum (German for ?empty room?). Scientists would fire a high-energy laser at the inner surface of this gold can, to create a thermal radiation field, generating light similar to the light emitted by stars.
They would then direct the photon beam from the first stage of the experiment through the centre of the can, causing the photons from the two sources to collide and form electrons and positrons. It would then be possible to detect the formation of the electrons and positrons when they exited the can.
?Although the theory is conceptually simple, it has been very difficult to verify experimentally. We were able to develop the idea for the collider very quickly, but the experimental design we propose can be carried out with relative ease and with existing technology,? said Oliver Pike, leader researcher. ?Within a few hours of looking for applications of hohlraums outside their traditional role in fusion energy research, we were astonished to find they provided the perfect conditions for creating a photon collider. The race to carry out and complete the experiment is on!?
Source: Imperial College London press release
Pix credit: Imperial College London