Speaker
Description
Most thermodynamic systems live and die by the Boltzmann exponential;
the standard occupation functions (Fermi-Dirac, Bose-Einstein, and
Boltzmann) are defined by it. In discrete energy systems, state
degeneracy is usually of secondary importance, while in continuous energy
systems, density of states functions may dominate the Boltzmann factor at
low energies but never at high. However, this need not be the case.
Recently, a new type of degeneracy (supradegeneracy) has been proposed in
which state degeneracy increases more quickly with energy than the
Boltzmann exponential, thereby dominating it at high energies. The result
are systems that display a form of population inversion at thermal
equilibrium without the need for non-equilibrium pumping. No naturally
occurring supradegenerate systems appear to exist; however, analysis
indicates man-made supradegenerate systems should be constructable. Some
are predicted to have remarkable properties, including allowing tests of
the limits to the second law of thermodynamics.
In this presentation, the essentials of supradegeneracy will be reviewed
and second law tests proposed. Laboratory experiments (currently in
progress) will be described in which supradegeneracy is being
investigated. These involve silicon that is differentially doped with
p-type impurities near its valence band edge, forming a suprathermal
"energy ladder" up into the band gap. It is predicted that electrons can
climb the ladder to suprathermal energy states (E >> kT) driven solely by
thermal energy from the lattice. Should these silicon experiments
demonstrate the effect, efforts will be made to build energy ladders
across the entirety of narrow-gap semiconductors. This should allow new
and sensitive tests of the absolute status of the second law.
