Statistical Fluctuations in Devices

Abstract

Fluctuations are inherent in all of the devices that we make. The simple fact that they are formed at finite temperature means that they are formed with finite entropy. Using one of the most basic definitions of entropy (Landau and Lifschitz, 1980),

$$ S = k_B \log \left( {Number of states consistent with external constraints} \right), $$

implies that we have more than one possible state (typically configuration) of our device that we have prepared at the finite temperature. It has been long realized that fluctuations would eventually limit the reproducibility of devices (Keyes, 1972). Yet today we are begining to explore devices where these fluctuations may play a very important role.