In 1961, Rolf Landauer published a landmark paper titled "Irreversibility and Heat Generation in the Computing Process" in which he observed that irreversible computational processes emit heat. Landauer's principle is significant because it provides a direct link between physics and information theory, and, as of this writing, the full importance of this connection is not fully understood.1

Thirteen years prior to Landauer's discovery, Claude Shannon launched the field of information theory with his seminal paper A Mathematical Theory of Communication. In this paper, Shannon defined the notion of information entropy, which quantifies the information content of any particular message.2 Interestingly, information entropy H was so named NOT because of a direct link to the thermodynamic quantity S, but because the formulas for S and H look exactly the same...