In two weeks, I am giving two lectures about degenerate Fermi gases in a third-year undergraduate course on statistical mechanics. The textbook is the beautiful book by Schroeder. I want to highlight a few things that are amazing about the Fermi energy.1. It is given by an incredibly simple expression. EF = ℏ2 2m (3π2n)2/3 2. Besides fundamental constants, it is only determined by the number density of fermions n.3. It is relevant to diverse systems: electrons in a metal, liquid 3He, electrons in a white dwarf star, neutrons in a neutron star, ultracold fermionic atoms such as 6Li. The...