Fluctuation theory and (very) early statistical energy analysis (SEA).

The equivalence between a noise source in combination with a resistance, and a thermal bath, is a part of fluctuation theory. This observation was the motivation for the author’s 1960 calculation of the power flow between modes of vibration excited by random noise sources. The resulting relation between power flow and uncoupled energy of vibration is therefore more than a thermal analogy; it is an actual representation of two thermal baths in contact. In a sense, the answer was known before the calculation was performed; the power flow had to be proportional to the differences in modal energy. The calculation merely determined the thermal conductivity of the connection. The relations for groups of modes in contact and the proportionality between power flow and actual modal energy came later. © 2003 Acoustical Society of America. @DOI: 10.1121/1.1567274#