“This provides a natural framework, a bookkeeping mechanism, for assembling very large numbers of Feynman diagrams,” says Marcus Spradlin, a physicist at Brown University who is beginning to use new tools in surface studies. . “Information is becoming dramatically more compact.”
Unlike oscilloscopes, which required exotic particles to provide the balance known as supersymmetry, surface science applies to more realistic non-supersymmetric particles. “It’s completely agnostic. I wasn’t at all agnostic about supersymmetry,” Spradlin said. “I think it was a real surprise to some people, including myself.”
The question now is whether this new, more primitive geometric approach to particle physics will allow theoretical physicists to leap beyond the limits of space and time altogether.
“We needed to find the magic, and perhaps this is it,” said Jacob Bourjailly, a physicist at Pennsylvania State University. “I don’t know if space and time will disappear. But I’ve never seen a door before.”
Feynman’s problem
Figueiredo felt the need for new magic firsthand during the waning months of the pandemic. She was tackling a challenge that has puzzled physicists for more than 50 years: predicting what happens when quantum particles collide. In the late 1940s, solving the charged particle problem required years of effort by three of the brightest postwar minds: Julian Schwinger, Shinichiro Tomonaga, and Richard Feynman. Their ultimate success would earn them a Nobel Prize. Because Feynman’s scheme was the most visual, it came to dominate the way physicists thought about the quantum world.
When two quantum particles combine, all sorts of things can happen. They can combine into one, split into many, disappear, or occur in the above order. And what actually happens is, in a sense, a combination of all these and many other possibilities. A Feynman diagram tracks what happens by connecting lines that represent a particle’s trajectory through space-time. Each diagram captures one possible sequence of subatomic events and provides a numerical equation called the “amplitude” that represents the probability that that sequence will occur. Physicists believe that if you add up enough amplitudes, you get stones, buildings, trees, and people. “Almost everything in the world is a chain of things happening over and over again,” Al-Kani Hamed said. “It’s just good old things bouncing off each other.”
There is a mysterious tension inherent in these amplitudes that has puzzled generations of quantum physicists going back to Feynman and Schwinger himself. People spend hours at blackboards sketching Byzantine particle trajectories and evaluating terrifying formulas, only to find that terms cancel out and complex equations dissolve into very simple answers, typically You may notice that it literally leaves the number 1 behind.
“The level of effort required is enormous,” Bourjai said. “And every time your predictions mock you with their simplicity.”
