fermion

Etymology

From Fermi + -on. Named after Italian-American physicist Enrico Fermi. Coined by English physicist Paul Dirac in 1945 in a lecture titled "Developments in Atomic Theory".

noun

1. (particle physics, Standard Model) Any elementary or composite particle that has half-integer spin and thus obeys Fermi–Dirac statistics and the Pauli exclusion principle (equivalently, a particle for which the wavefunction of any system of identical such particles changes sign whenever two are swapped); a baryon, a lepton or a quark;
   The fermions treated by the Standard Model are the (composite) baryons and the (elementary) leptons and quarks.
   According to the spin–statistics theorem, the wavefunction of a system of identical fermions (particles of half-integer spin) is antisymmetric under the operation of swapping any two particles.
   A remarkable feature of lattice regularization is the appearance of several fermion species per fermion field in the lattice action. 1994, István Montvay, Gernot Münster, Quantum Fields on a Lattice, Cambridge University Press, page 208
   For 2D systems, going beyond first order pertu[r]bative calculations, we show that the second harmonic of the current is strongly suppressed in the case of spinless fermion models but significantly enhanced for the Hubbard model. 1996, Georges Bouzerar, Didier Poilblanc, “Persistent Currents in Interacting Electronic Systems”, in T. Martin, G. Montambaux, J. Trân Thanh Vân, editors, Correlated Fermions and Transport in Mesoscopic Systems, Editions Frontieres, page 149
   It is not known whether the Higgs mechanism is the true source for the masses of the fundamental fermions. 1996, Georg G. Raffelt, Stars as Laboratories for Fundamental Physics, University of Chicago Press, page 253
   The snapshots were taken by MIT physicists and are the first images that directly capture the pairing of fermions — a major class of particles that includes electrons, as well as protons, neutrons, and certain types of atoms. 2023-07-06, Jennifer Chu, “MIT physicists generate the first snapshots of fermion pairs”, in MIT News