Ever since the 1960s, when the food synthesiser made its appearance in Star Trek, the idea of a machine that could seemingly make something from nothing has been the kind of tech we dream about. But the actual technology may not be as implausible as previously thought.
In 1934, Gregory Breit and John Wheeler theorised that, if you smashed two photons -- light particles -- together, the collision would create an electron and a positron (its antimatter equivalent). Breit and Wheeler never thought that their theory, simple though it was, could be proven. It is a rare occurrence that is difficult to reproduce, and has never been observed in a laboratory setting.
However, three physicists at the Imperial College of London have figured out a way to prove the 80-year-old theory. Led by researcher Oliver Pike, the team has devised a machine called the "photon-photon collider" which could hold the answer. The collider uses existing technologies and requires two key steps.First, a high-intensity laser would be used to speed up electrons until they are almost at light speed. These electrons would be fired at a slab of gold, which would create a beam of photons a billion times more energetic than the speed of light.
Next, a high-energy laser would be fired into a small gold canister called a hohlraum (German for "cavity"). This would create a thermal radiation field, generating light similar to that of stars.
The photon beam would then be directed into the hohlraum, where photons from the two different sources would collide, forming around 100,000 electron-positron pairs, which could be detected as they exited the hohlraum.
"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," said Department of Physics Professor Steven Rose.
"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."
The team plans to set up and conduct the experiment within 12 months.
"Although the theory is conceptually simple, it has been very difficult to verify experimentally," Pike said. "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. 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!"
Of course, from there it's a long way to molecular assembly -- but the dream lives on.
The team's research can be read in the journal Nature Photonics.