Degeneracy Temperature

the temperature below which the quantum properties of an ideal gas, which depend on the identity of particles, appear clearly—that is, the gas becomes degenerate. For a Bose gas of particles with nonzero mass, the degeneracy temperature is defined as the temperature below which Bose-Einstein condensation occurs—the transition of some part of the particles of the system into a state with zero momentum. For a Fermi gas the degeneracy temperature is equal to the maximum particle energy at absolute zero, expressed in degrees (that is, divided by the Boltzmann constant); at the degeneracy temperature, almost all the lower energy levels of a Fermi gas are filled.