Population Inversion without Pumping: Supradegeneracy

Population inversion, the primary thermodynamic phenomenon behind most lasers and masers, is thought to require nonequilibrium pumping; for lasers this typically involves optical or electronic excitation, electric discharge, or chemical reactions. In this talk it is shown from first principles that population inversion does not require pumping, but instead can arise spontaneously at equilibrium when the degeneracy of a system increases quickly enough to dominate its
Boltzmann exponential. Examples of this supradegeneracy have not yet been identified in Nature, however they appear possible to create by design. Potential structures and applications of solid state supradegenerate systems will be discussed.