Physicists Attempt to Turn Light Into Matter with 84-Year-Old Theory
A team of physicists are about to attempt the theoretically-possible-but-yet-impossible task of transforming light into matter.
The process called the Breit-Wheeler process is over 84 years old, and it effectively flips around E=mc^2 into m=E/c^2. Led by professor Steven Rose, physicists from the Imperial College London developed a way to finally test out the popular theory. Breit-Wheeler states that if two particles of light (photons) are smashed together, they can create an electron and a positron (a particle with the same mass as an electron an a numerically equal but positive charge).
Rose said the students plan on putting Einstein's famous equation to the test.
"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 matter is turned to energy," Rose said in a statement. "What we are doing is the same but backwards: turning photon energy into mass, i.e. m=E/c2."
The team needed to create a unique setup to properly test the theory. They used a photon-photon collider -- two high-power laser beams that create the photons of light that will eventually be smashed together. According to the researchers, one photon has 1,000 times the energy of photons that produce visible light. The other photon beam has one billion times the energy.
The two lasers then go into a target chamber where the electrons are fired at a slab of godl to produce high-energy photos. There's also a second high-energy laser fired into a gold tube that creates a thermal radiation field called a hohlraum.
The team looked around the world for a suitable set up, but nothing really worked. They finally decided on the Gemini laser at the Central Laser Facility near Oxford.
Upon getting the results, the physicists will have to carefully analyze the data -- even if they successfully detect positrons. Some of the positron detectors are coming from CERN. Thoroughly digging through the data will tell the team if the positrons were created through the Breit-Wheeler process or from another background event. They also won't be sifting through data on their own; they plan on building out a network of partnering schools to help them through the Institute for Research in Schools (an organization which Rose helped found).
If they really do discover a Breit-Wheeler positron, the young physicists will have proven that it's possible to successfully turn light into matter.
"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," Mangles said.
"If we can demonstrate it now," Mangles continued, "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."
The experiment has been in the works since 2014, and early research can be found in the journal Nature Photonics.