Enrico Fermi’s first discovery

I published my first significant work, the Theory of Fermion behaviour, in February 1926.

The fame of the article reached as far as England; the English physicist Paul Dirac (1902-1984) read it, but he immediately forgot about it because the problem did not fall within his interests at the time. Yet, a few months later, in October 1926, he approached the question, devising a slightly different method, and arrived at the same conclusions. I then decided to write him a letter to claim the priority of the discovery.

Dear Sir,
In your interesting paper “On the theory of quantum mechanics” (…), you have put forward a theory of the Ideal Gas based on the Pauli exclusion principle.
Now, a theory of the Ideal Gas that is practically identical to yours was published by me at the beginning of 1926.

Dirac – like a true gentleman – promptly responded with a letter of apology, which marked the birth of the Fermi-Dirac theory.

But why is this theory so critical?
In practice, anything that wanders around in the atomic and subatomic world is a Fermion – a particle that behaves according to the Fermi-Dirac theory) –  or a Boson – a particle that behaves according to 1924 Bose-Einsten statistics.

The difference between the two types of particles is that Bosons always want to be together, while Fermions refuse to be together.
Particles of matter are Fermions: the solidity of a piece of iron lies in the refusal of atomic electrons to share space with their neighbours. They are loners.
Particles of light, such as Photons and other particles in the subatomic world, such as the Higgs Boson, are Bosons.
The tendency of Photons to stay together and all do the same thing is the basis of the power and precision of a laser light beam.