Dan Yue , '05

Date of Award

Spring 2005

Document Type

Restricted Thesis

Terms of Use

© 2005 Dan Yue. All rights reserved. Access to this work is restricted to users within the Swarthmore College network and may only be used for non-commercial, educational, and research purposes. Sharing with users outside of the Swarthmore College network is expressly prohibited. For all other uses, including reproduction and distribution, please contact the copyright holder.

Degree Name

Bachelor of Arts

Department

Physics & Astronomy Department

First Advisor

Michael R. Brown

Abstract

Today, we find an increasing interest in Brownian motors—theoretical "thermal ratchets" that rectify random motion to do work. This interest stems not only from possible applications to cellular transport mechanisms and nanoscale mechanics but from the more intricate understanding of entropy and non-equilibrium dynamics they offer. In an attempt to bring Brownian motors one step closer to reality, the primary goal of this paper is to propose an experimental realization of an (electronic) thermal ratchet and predict its behavior numerically; with a secondary goal of exploring the practicality and properties of this ratchet and putting this research in the context of existing thermal ratchet work. To these ends, we present a general discussion of non-equilibrium dynamics and the state-of-the-art in thermal ratchet research. Following this, we explain the electronic ratchet, a diode and resistor in parallel where the diode rectifies the Nyquist noise across the resistor, in detail. Finally, we determine that an experimental electronic ratchet using off-the-shelf components can exhibit a measurable voltage difference 14.5pV /° K, which could confirm this effect experimentally. We also show that this effect is independent of the Seebeck effect, meaning that there are unlikely to be any other "antagonistic" thermoelectric effects to muddle any experimental results.

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