Experimental realization of a Szilard engine with a single electron
  The most succinct manifestation of the second law of thermodynamics is the limitation the Landauer principle imposes on the amount of heat a Maxwell demon (MD) can convert into free energy per single bit of information obtained in a measurement. We suggest and experimentally realize a reversible electronic MD based on a single-electron box operated as a Szilard engine, providing the first demonstration of this limitation: extraction of kT ln 2 of heat from the reservoir at temperature T per one bit of created information. The information is encoded in the position of an extra electron in the box. 
J. V. Koski, V. F. Maisi, J. P. Pekola, and D. V. Averin
cond-mat.mes-hall