See also: Boson (homonymy)
The bosons represent a class of particles which have particular properties of Symétrie during the exchange of particles: a behaving system of identical particles as bosons is always in a completely symmetrical state with respect to the exchange of particles. All the Elementary particles to date discovered are either of bosons, or of the Fermion S, the latter being able to be only in one completely antisymmetric state with respect to the exchange of particles. The Théorème spin-statistics indicates that the particles of whole Spin are bosons, whereas the particles of spin half-entirety are fermions.
The term of boson comes from the name of the physicist Satyendranath Bose and would have been used for the first time by Paul Dirac. Bump carried out the first that to explain the law of Planck describing the radiation of the black body starting from the Photon S previously discovered by Einstein, it had to be supposed that the photons do not follow the Statistique of Maxwell-Boltzmann, but rather statistics from now on called Statistique of Bump-Einstein. Bump writes a short article, Planck' S Law and the Hypothesis off Light Quanta , which it sends to Albert Einstein, after a rejection by the Philosophical Magazine . Einstein is favorably impressed and recommends it for publication in Zeitschrift für Physik , and it does itself of it the translation of the English towards the German . Einstein also will extend the concept of boson to other particles such as the atoms and will contribute to the popularity of the concept of boson.
Exchange identical particles in quantum mechanics
See also: indistinguishable Particles
The fact that in quantum mechanics the particles do not follow a given trajectory makes the identification of the particles completely impossible. In other words, the particles are indistinguables one of the other, and do not have clean individuality. It follows that a measurement supplements on each particle cannot be enough to characterize the state of the system completely, this phenomenon being called degeneration of exchange.
To illustrate what one understands by degeneration of exchange, let us suppose given a complete Ensemble of observable which commutates (ECOC) for a particle and note