Ralph Chamberlin joined Arizona State University in 1986. He studies the thermal and dynamic properties of materials. His career has shifted between experiments, theory, and computer simulations. He has been involved in developing and interpreting stretched-exponential relaxation for spin glasses, non-resonant spectral hole burning for supercooled liquids, and nanothermodynamics for the thermal and dynamics properties of complex systems on the scale of nanometers. Practical applications of his research include characterizing and controlling excess thermal fluctuations (“hot spots”) in advanced materials, and a basic understanding of how nanometer-sized thermal fluctuations can cause bits of magnetic memory to forget their alignment.
Ph.D. University of California-Los Angeles
A practical application of our research is to understand how thermal fluctuations might erase magnetic memory when the recorded bits reach the scale of nanometers. Another application is to explain how nanometer-sized hot spots occur inside bulk materials. Several experimental techniques have shown that these thermal fluctuations are localized, uncorrelated with neighboring fluctuations, thereby deviating from standard thermodynamics that requires an effectively infinite and homogeneous heat bath. In 1878 Gibbs introduced the chemical potential, which accommodates the thermal energy of individual particles. In 1962 Hill introduced the subdivision potential, which accommodates the thermal energy of individual fluctuations. We find that Hill’s subdivision potential is essential to ensure conservation of energy and maximum entropy during equilibrium fluctuations. We use this “nanothermodynamics” as a guide to develop experiments, theories, and computer simulations. Experiments that we pioneered include: ultrafast SQUID magnetometry, time-domain dielectric spectroscopy, nonresonant-spectral hole burning, vertical-cantilever force microscopy, and tickle-field electron microscopy. Theories that we develop utilize Hill’s fully-open nanocanonical ensemble, yielding a mesocopic mean-field theory and local Landau theory for phase transitions. Computer simulations that we investigate include nonlinear corrections to the total energy from changes in local entropy applied to the Ising model, Creutz model, and molecular dynamics. We have shown that nanothermodynamics provides a fundamental foundation for several formulas that have been known empirically for many years, including stretched-exponential relaxation (1854), super-Arrhenius activation (1921), non-classical corrections to critical scaling (1893), and 1/f noise (1925). The fundamental goal of our research is to understand these empirical formulas, including commonly measured deviations, using nanoscale corrections to classical thermodynamics and statistical mechanics.
Summer 2022 | |
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Course Number | Course Title |
PHY 792 | Research |
Spring 2022 | |
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Course Number | Course Title |
PHY 334 | Advanced Laboratory I |
PHY 493 | Honors Thesis |
PHY 499 | Individualized Instruction |
PHY 584 | Internship |
PHY 792 | Research |
PHY 799 | Dissertation |
Fall 2021 | |
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Course Number | Course Title |
PHY 334 | Advanced Laboratory I |
PHY 792 | Research |
PHY 799 | Dissertation |
Summer 2021 | |
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Course Number | Course Title |
PHY 792 | Research |
Spring 2021 | |
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Course Number | Course Title |
PHY 334 | Advanced Laboratory I |
PHY 493 | Honors Thesis |
PHY 584 | Internship |
PHY 792 | Research |
PHY 799 | Dissertation |
Fall 2020 | |
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Course Number | Course Title |
PHY 334 | Advanced Laboratory I |
PHY 792 | Research |
PHY 799 | Dissertation |
Summer 2020 | |
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Course Number | Course Title |
PHY 792 | Research |
Spring 2020 | |
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Course Number | Course Title |
PHY 333 | Electronic Circuits/Measuremnt |
PHY 493 | Honors Thesis |
PHY 584 | Internship |
PHY 792 | Research |
PHY 799 | Dissertation |
Fall 2019 | |
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Course Number | Course Title |
PHY 334 | Advanced Laboratory I |
PHY 492 | Honors Directed Study |
PHY 792 | Research |
PHY 799 | Dissertation |
Summer 2019 | |
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Course Number | Course Title |
PHY 792 | Research |
Spring 2019 | |
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Course Number | Course Title |
PHY 333 | Electronic Circuits/Measuremnt |
PHY 465 | Advanced Laboratory II |
PHY 584 | Internship |
PHY 792 | Research |
PHY 799 | Dissertation |
Fall 2018 | |
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Course Number | Course Title |
PHY 333 | Electronic Circuits/Measuremnt |
PHY 792 | Research |
PHY 799 | Dissertation |
Summer 2018 | |
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Course Number | Course Title |
PHY 792 | Research |
Spring 2018 | |
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Course Number | Course Title |
PHY 333 | Electronic Circuits/Measuremnt |
PHY 465 | Advanced Laboratory II |
PHY 584 | Internship |
PHY 792 | Research |
PHY 799 | Dissertation |
Fall 2017 | |
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Course Number | Course Title |
PHY 792 | Research |
PHY 799 | Dissertation |