Fundamental theories of physics
Fermions
Gerard ’t Hooft
Abstract
Classical theories starting with continuous degrees of freedom will typically generate bosonic quantum objects; fermionic quantum objects in turn, arise when a classical system contains discrete degrees of freedom—typically: flip-flops. Here, we explain how anti-commuting operators enter the scene, and illustrate the situation using an elegant model: the idealized notion of a ‘neutrino’. What do neutrinos have in common with infinite, at sheets, and where does spin \(\frac{1}{2}\) come from? The associated mathematical tool kit is quite delicate. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.