Scientists trying to turn light into matter

In laser facilities in the UK, Imperial physicists are testing an 84-year-old theory which was once thought impossible to prove.

The target chamber, where the laser beams are focussed
The target chamber, where the laser beams are focussed

The hypothesis of the Breit-Wheeler process says it ought to be conceivable to transform light into the issue by crushing two particles of light (photons) together to make an electron and a Positron. However, past attempts to do this have required the addition of other high-energy particles.

Now, scientists from Imperial College London are trying to test the theory in the hope of turning light directly into the matter for the first time. They have come up with a way that involves two high-power laser beams, which are being used to create the photons of light to be smashed together.

A collection of experimentalists from Imperial and Jena in Germany
A collection of experimentalists from Imperial and Jena in Germany

The laser beams are focused on two separate modest focuses inside an objective chamber, which contains complex optics used to center the laser pillars and magnets used to redirect the charged particles. It is the charged positrons falling off the crash that the group will search for to affirm if the procedure was a success.

Professor Rose said: “This would be a pure demonstration of Einstein’s famous equation that relates energy and mass: E=mc2, which tells us how much energy is produced when the matter is turned to energy.  What we are doing is the same but backward: turning photon energy into mass, i.e. m=E/c2.”

The target chamber, with optics used to focus the beams
The target chamber, with optics used to focus the beams

The study is conducted under the guidance of Dr. Stuart Mangles and Professor Rose. Scientists primarily checked out the world for a reasonable laser system, yet found the most appropriate up close and personal: the Gemini laser at the STFC Rutherford Appleton Laboratory’s Central Laser Facility close Oxford.

At the experiment
At the experiment

Dr. Mangles said: “When Gregory Breit and John Wheeler first proposed the mechanism in 1934, they used the then-new theory of the interaction between light and matter known as quantum electrodynamics (QED). Whereas every other fundamental prediction of QED has since been demonstrated experimentally, the ‘two-photon Breit-Wheeler process’ has never been seen.

“If we can demonstrate it now, we would be recreating 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.”