100 years of Einstein's theory of Brownian motion: from pollen grains to protein trains-1

Abstract

Experimental verification of the theoretical predictions made by Albert Einstein in his paper, published in 1905, on the molecular mechanisms of Brownian motion established the existence of atoms. In the last 100 years Brownian motion has not only revolutionized our fundamental understanding of the nature ofthermal fluctuations in physical systems, but it has also explained many counterintuitive phenomena in earth and environmental sciences as well as in life sciences. This 2-part article begins with a brief historical survey and an introduction to the concepts and theoretical techniques for studying Brownian motion. Then, in Part 2 a discussion on rotational Brownian motion and Brownian shape fluctuations of soft materials is followed by an elementary introduction to two of the hottest topics in this contemporary area of interdisciplinary research, namely,stochastic resonance andBrownian ratchet.