On fermion’s problems, when all the low-energy states are already occupied
If we neglect the possibility of turning them into particles of another sort, a quantity of identical particles can represent the ideal gas, where the range of particle’s speeds is described by the Maxwell-Boltzmann’s law. However, with decreasing temperature or increasing concentration of the particles, their behavior becomes quite unusual in terms of classical ideas, and different for bosons and fermions. The energy of the fermions, according to the Pauli exclusion principle, couldn’t be equal and is distributed among them according to the Fermi-Dirac’s law. The bosons can have almost equal energy as it takes place in a laser beam. With decreasing temperature, bosons are slowed down and, under certain conditions, come all to the state with the same minimum energy, thereby forming the so-called Bose-Einstein condensate.