CAREER: Activated Escape in Nonequilibrium Micromechanical Oscillators - Research and Education Program

University Of Florida, Gainesville FL

Investigators

Abstract

Non-Technical Abstract: Fluctuations play a crucial role in many physical and biological phenomena at the micro- and nanoscale. A system can be induced to switch out of a metastable state when fluctuations are sufficiently large. Even though such transitions may occur infrequently, they largely determine the behavior of systems with multiple stable states. The goal of this Faculty Early Career Award at the University of Florida is to study fluctuation-induced switching in a mechanical device with features as small as a millionth of a meter. When this device is periodically driven, it oscillates with one of two distinct amplitudes. In the presence of fluctuations, the oscillation amplitude switches between the two stable values. The research will focus on revealing generic fluctuation phenomena that occur not only in our micro-scale mechanical system but also in other nonequilibrium systems. Such studies will answer open questions and enhance the understanding of fluctuations in systems that are far from equilibrium. Even though the proposed research is of fundamental nature, the findings could open possibilities for new detection schemes and signal-processing applications using micro-scale mechanical devices. In terms of outreach, the program will provide summer research experiences for high school students. Furthermore, demonstration materials will be developed for the students to bring back to their schools to further enhance the educational impact. Micromechanical devices will also be used to enhance teaching in an introductory mechanics course. Technical Abstract: The goal of this Faculty Early Career Award at the University of Florida is to study activated switching between coexisting stable states in systems far from thermal equilibrium. Experimental studies will be carried out using an underdamped nonlinear micromechanical torsional oscillator. Under a sufficiently strong periodic driving field, the oscillator possesses two stable dynamical states with different oscillation amplitudes within a certain range of driving frequencies. The research will focus on revealing the scaling behaviors of the activation barrier with varying system parameters and generic features of fluctuations in the parameter range where stationary populations of the stable states are close to each other. Such studies will allow verification of the existing predictions, answer open questions on fluctuations in nonequilibrium systems and stimulate new theoretical research. Even though the proposed research is of fundamental nature, the findings could open possibilities for novel sensing schemes and signal-processing applications using micromechanical devices. In terms of outreach, the program will provide summer research experiences for high school students. Furthermore, demonstration materials will be developed for the students to bring back to their schools to further enhance the educational impact. Micromechanical devices will also be used to enhance teaching in an introductory mechanics course.