Experimental Search for Supradegeneracy*

Recently a new statistical mechanical phenomenon has been
formally identified that turns some thermodynamic intuitions on their
heads: supradegeneracy [1]. Normally, population inversion (as in
lasers) requires nonequilibrium conditions, but supradegenerate
systems are predicted to exhibit inversion at equilibrium. If
realized, this phenomenon might help lead to improved photovoltaics and
to new types of thermophotovoltaics and batteries [2]. Although
supradegenerate systems do not appear in Nature, it seems likely that
manmade ones can be realized. This talk reviews the current laboratory
search for supradegeneracy in condensed matter systems, specifically, in
semiconductors and concentration-graded ionomer membranes.
[1] D.P. Sheehan and L.S. Schulman, Physica A 524, 100 (2019).
[2] D.P. Sheehan, Sustain. Energy. Tech. Assess., in press (2019).