Lecture 10 - Quantum Statistics and the Fermi-Dirac distribution
Fermi-Dirac statistics describes the energy distribution of a non-interacting gas of identical particles with half-integer spin angular momentum. Despite the many successes of this in explaining various terrestrial systems, the most spectacular application of Fermi-Dirac has been, without doubt, in the area of stellar physics, in particular in explaining the physics of stellar remnants (white dwarfs, neutron stars).
The dependence of the pressure of the gas on the density and temperature plays a crucial role in the evolution of the stars as they age. The evolution is very different for stars in which the gas obeys classical Boyle’s law, compared to stars in which the gas obeys the rules of quantum physics. As a prelude to a detailed discussion of the life history of stars in the subsequent lectures, in this lecture we discuss the Fermi-Dirac distribution, which is obeyed by electrons, protons, neutrons, etc.