字幕表 動画を再生する 英語字幕をプリント Physicists love particles, and with good reason – almost everything in the universe is made up of particles, so the physicist’s approach to understanding the universe is to understand the particles that make it up. If you want to discover and catalogue new particles (which physicists do), here are three approaches you can take. First, you can take old particles we already know stuff about and just stick them together to build new *composite* particles. That’s what chemists and molecular biologists spend a lot of their time doing, and it’s kind of like figuring out what you can build with legos. Second, you can smash old particles together with ever increasing violence, either hoping to break an old particle apart into previously unknown constituents or to excite a new particle into existence from the quantum fields that underly all reality. Sometimes this works and the smashing reveals an entirely new *fundamental* building block of the universe like quarks or the Higgs boson. But most of the time it just makes a big mess, an explosion of old particles we already know about. Third, you can put old particles in new environments so that they behave differently, or put old particles together in new ways so that new particle-like behaviors emerge through their *collective* quantum interactions. For example, in certain crystals, the particles that move around are not electrons themselves but in fact holes or gaps in a densely packed sea of electrons. Or, when you make certain materials really really cold, free electrons in them stop acting like electrons and team up in pairs to act like weird electron-only atoms that move around with essentially no resistance. Or when you make certain metals really cold, electrons in them start acting as if they were 1000 times *heavier* than normal. Or if you make a super thin essentially 2-dimensional sheet of gallium arsenide with a perpendicular magnetic field and parallel electric field and make it really cold, electrons start behaving as if they had an electric charge that’s a fraction of what they normally do. Or if you force electrons into a special 1-dimensional line, the particles that move back and forth along that line *look* like electrons, except separated so that some of them have the charge of an electron but no spin, while others have the spin but no charge. Or if you cool helium down super super cold, you’ll find emergent particles that behave like higgs bosons! These emergent higgs bosons were first discovered in 1973, 40 years before the higgs boson fundamental particle was discovered at the Large Hadron Collider by violently smashing together protons. Of course, the particles that emerge when you put collections of electrons together in materials aren’t fundamental constituents of the universe, but they’re far more diverse and bizarre and weird and cool. And unlike searching for fundamental particles where you just have to wait and see what nature has in store, we can actively find and curate new emergent particles simply by making different weird materials that allow their emergent properties to come to life. Plus, materials with emergent particles have real and far-reaching practical technological use: in electronics, computer chips, levitating high speed trains, and even the magnets and detectors used to discover the higgs boson at the Large Hadron Collider. This video was supported in part by the Gordon and Betty Moore Foundation’s Emergent Phenomena in Quantum Systems Initiative. EPiQS supports discovery-driven research on novel electronic materials and aims to stimulate breakthroughs to fundamentally change our understanding of the organizing principles of complex matter. To learn more, visit Moore.org or follow the Moore foundation on twitter.