In 30 seconds
Jim Gates describes supersymmetry as completing a lopsided picture of particles: matter and force carriers each get a new partner, filling two empty quadrants of a pie. He explains why he was drawn to the idea as a graduate student, why symmetry that is broken matters most, and how Einstein's light-bending prediction and the Higgs boson show the pattern of calculating first and testing later.
- 1Supersymmetry fills the empty half of a lopsided picturePut matter particles in one quadrant and force carriers in another, and the two empty quadrants beg for partners, which supersymmetry supplies.
- 2Gates chose supersymmetry because few others were studying itAs a graduate student in the mid-1970s he looked for a direction other people were not exploring, and the mathematics "bowled me over".
- 3If symmetries were perfect, we would not existSymmetry is a scaffold for reality, but it is only when balance is broken that humans, planets and stars emerge.
- 4Mathematics is a palette for physicistsChanging one term in the equations for light or the electron produces a partner particle, the photino or selectron, in much the way a composer writes variations on a theme.
- 5Modern physics often calculates first and experiments laterEinstein's 1915 equations predicted that gravity bends light, and the Higgs boson was likewise predicted decades before it was found; supersymmetry is still waiting for its test.
Read the full transcript by chapter
A lopsided pie of particles points to a hidden symmetry
Asked by Lex Fridman what supersymmetry is, Gates asks him to picture a pie with four quadrants. In one he places the matter particles, such as electrons and quarks, and in another the force carriers. The other two quadrants are empty, and Gates says humans have a deeply programmed sense of symmetry, so the picture immediately looks wrong.
One way to restore balance is to put something in those empty quadrants, and that is supersymmetry. Gates says he understood the idea as a graduate student at MIT in 1975, when its mathematics was still new. It had first been born in the Ukraine in the late 1960s, but the Iron Curtain kept Western scientists from knowing, and Bruno Zumino and Julius Wess rediscovered it independently in the early 1970s.
Gates explains that he wanted to maximize his chances of success by working in a direction few others were studying. His advisor, James Young, had taught him about electrons and the weak force, but when Gates surveyed emerging ideas, supersymmetry's mathematics bowled him over. He holds two undergraduate degrees, mathematics first and physics second, although his heart was always in physics.
Symmetry is a scaffold for reality, and the magic happens when it breaks
Fridman asks about the most beautiful idea in mathematics and physics, and Gates answers: symmetry. He finds it striking that our innate sense of symmetry lines up with powerful mathematics. Yet he points out that perfect symmetry would mean no humans, because it is only when balances are broken that creatures, planets and stars appear.
Symmetry is therefore a scaffold for reality but not the whole of it. Gates says he is naturally drawn to areas of science where symmetry plays a dominant role, and Fridman sums up that the magic happens when you break the symmetry.
Changing one term in the math creates partner particles for the empty quadrants
To fill the quadrants, Gates returns to his earlier image of two flashlight beams passing through each other: light is made of force carriers called photons, which carry the electromagnetic force. He calls mathematics a palette, much like a composer constructing variations on a theme, and says that Maxwell's equations for light can be varied. One variation gives a force carrier that bounces off others like an electron does, which cannot sit in the force-carrier bucket and so must go in an empty quadrant. The photon's partner is called the photino.
The same trick works in reverse. Starting from the mathematics of the electron, developed by Dirac in the late 1920s and early 1930s, one can locate the term that makes two electrons bounce off each other and modify it so the particle carries charge but passes through others. Physicists name these new objects by putting an s in front, giving selectrons and squarks, which completes the balanced pie.
Gates was amazed that nobody else at MIT found this interesting, which led him to be the first person there to study supersymmetry seriously. In 1977 he wrote the first physics PhD thesis in the department on the subject, drawn, he says, by the balance and the symmetry.
Physics works by calculating first, then testing, as with Einstein and the Higgs
Fridman asks whether supersymmetry is fundamentally mathematical and how it stands experimentally, observing that it is closer to validation than string theory but has not yet been confirmed. Gates answers by turning to Einstein, the subject of his book Proving Einstein Right. Einstein's 1915 general relativity equations differed from Newton's and made three predictions, one of which, the orbit of Mercury, was really a postdiction because astronomers had already seen it deviate from Newton's expectation.
The second prediction was that gravity bends light, which Gates illustrates by moving a water glass between two faces so that one appears to shift. Newton also expected bending, he says, but Einstein predicted twice as much. Fridman notes how remarkable it is that a calculation plus a physicist's intuition can point to what an experiment should find.
Gates agrees that this is how fundamental modern physics works: someone writes down equations, the equations make a prediction, and experimentalists go looking. He gives the Higgs boson as another example, since in the late 1960s and early 1970s people wrote equations that predicted it, and later the search began.
More from this channel
3:36:56EN
Lex Fridman· Sep 16, 2026PodcastPsychiatry Has Never Found Its PenicillinHost Lex FridmanHistorian Andrew Scull tells Lex Fridman why the field can ease symptoms, has never cured a major mental illness, and keeps paying for overconfidence with patients' lives.
5:15:51ENLex Fridman· Aug 26, 2026Podcast · 2 speakersDHH Did Not Write a Line of Omarchy QuattroGuest DHH · Host Lex FridmanThirteen months after a skeptical conversation with Lex Fridman, the Rails creator describes how Opus 4.5, a swarm of coding agents, and a one-minute Linux installer ended his era of hand-chiseled Ruby.
3:12:58ENLex Fridman· Aug 12, 2026Podcast · 2 speakersOne Cold Shower, Twenty Champions: How Khabib Nurmagomedov Was ForgedGuest Khabib Nurmagomedov · Host Lex FridmanIn a Makhachkala school gym, seventy men shared one shower, and the water was only cold.
3:46:18ENLex Fridman· Jul 28, 2026Podcast · 2 speakersIf You Take Slavery Out of the Picture, There Is No Civil WarGuest Gary Gallagher · Host Lex FridmanIn 1860, enslaved people were worth more than every railroad and factory in the United States combined.
3:51:47ENLex Fridman· Jun 30, 2026Podcast · 2 speakersForty-Six Percent of Emperors Were Overthrown. The Empire Lasted AnywayGuest Anthony Kaldellis · Host Lex FridmanHistorian Anthony Kaldellis walks Lex Fridman through 2,200 years of Roman history and argues that what we call Byzantium was Rome itself.
2:53:42ENLex Fridman· May 29, 2026Podcast · 2 speakersThe Moon Is Falling. It Just Keeps Missing.Guest Biggest Mysteries in Physics · Host Lex FridmanFermilab physicist Don Lincoln tells Lex Fridman that the history of physics is a history of unification, and that antimatter, dark energy, and a theory of everything still sit far beyond the experiments we can run.