IRFP: Nonequilibrium Thermodynamics of Microscopic Machines

Horowitz Jordan M, Washington DC

Investigators

Abstract

The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad. This award will support a twelve-month research fellowship by Dr. Jordan M. Horowitz to work with Dr. Juan M. R. Parrondo at Universidad Complutense de Madrid in Madrid, Spain. The world's smallest machines function in a microscopic world very different from our everyday experience: inertia no longer plays a role and erratic thermal fluctuations create a violent operating environment. Nevertheless, we have learned that cells of all living organisms abound with molecular machines, one thousand times smaller than the width of a human hair, yet capable of performing an astounding variety of useful tasks -- such as ferrying cargo throughout the cell, transporting ions across the cell membrane or synthesizing adenosine triphosphate, the cell's battery. In addition, molecular complexes -- such as cantenanes, rotaxanes, and nanocars -- are being synthesized in labs around the world that can execute specific tasks on command. Unfortunately, our intuition from conventional macroscopic theories, such as thermodynamics, no longer applies. New theories and new design principles are needed to describe the truly nonequilibrium behavior of these small machines. This award supports three research projects that investigate nonequilibrium thermodynamics and statistical mechanics with applications to the operation of microscopic machines. The first project explores how information generation can act as a thermodynamic force in Brownian motors with feedback. The second project is to develop a control theory for nonautonomous microscopic machines by analyzing generic models called stochastic pumps. The final project investigates fundamental aspects of quantum thermodynamics through investigations into the nature of thermodynamic work in nonequilibrium quantum systems. Microscopic machines are ubiquitous in nature and artificial ones are continually being synthesized. Potential benefits of this project include applications to biophysics, new insights into the "engineering" of microscopic machines, as well as new nanotechnologies. Besides the practical benefits, this project integrates a variety of fields within the physics community, and promotes scientific collaborations with one of the largest and most active communities studying small far-from-equilibrium systems in the world.