Matthew Deady

PHYSICS INTERESTS

Most of my professional time is spent teaching and working with individual students, which is how I like it. But beyond the actual classes, the courses I have taught in my years at Bard continually expand my involvement in science and my intellectual engagement. You can consult the list of those courses on this website to get some sense of the range of interests I have as a teacher, and here you can read below about the physics projects I have been engaged in.

My Ph.D. research was done under the supervision of Dr. Claude F. Williamson at the MIT-Bates Linear Accelerator. This was an intermediate energy (300 - 900 MeV) electron accelerator outside of Boston. I collaborated on a variety of nuclear structure experiments from 1979 - 1995, and my own work involved deep inelastic electron scattering off of two isotopes of Calcium – ⁴⁰Ca and ⁴⁸Ca. In these experiments, the electron transfers enough energy to the nucleus to knock a single nucleon (proton or neutron) out of the nucleus. By analyzing the energy and momentum dependence of these collisions, we could draw inferences about the distribution and binding of the nucleons in the nucleus. The basic question we were addressing was, "When it is in a nucleus, is a nucleon a distinct particle or is it drastically modified by the presence of other nucleons?"

Groups at Bates and other laboratories performed experiments on nuclei from Deuterium to Uranium, and the answer to that question is still not totally clear. Some good theoretical models give a reasonable mechanism that explains both the charge and current interactions that are seen in deep inelastic scattering experiments. We had hoped to do one large, definitive experiment at Bates to settle the remaining issues, but limits on available beam time and resources shelved that proposed experiment. Recent and planned experiments at Brookhaven's Relativistic Heavy Ion Collider promise to some light on this question in the next few years.

The winding down of my Bates experiments coincided with my increasing interest to do more experiments on a small scale here at Bard. A topic of particular interest to me was musical acoustics, primarily how various musical instruments work. This combines my interest in music with my science studies, and it grew out of the grappling with these ideas I do in teaching my Acoustics course. For the past ten years or so, I have been doing a variety of experiments on simple systems that can be taken as analogous to musical instruments, such as vibrating metal bars and plates.

My formal initiation into this field was a project on non-linear acoustics I worked on with my colleague Burt Brody. More recently, my collaborators have included Rich Slesinski, a local high school physics teacher, and Bard students Chris Grinnan, Bucky Purdom, Eduardo Rozo, Zach Watkinson, Amanda Holt, and Chris Grinnan. We have tried to understand the behavior of some vibrating systems by examining them experimentally (i.e., by Fourier Analysis of their normal modes), analytically (by differential equation models of the system), and by computer modeling for numerical solutions of the modes of vibration. We don't have anything earth-shaking to report, but we are all learning a lot, and that's what counts.

Ever since I spent my 1993 sabbatical immersed in a study of chaos, I have dabbled in the study of non-linear dynamics. This field seems well-suited to my interests and abilities, since the study of it requires combining in-depth mathematics, experimentation, subtle data analysis, and computer modeling of the effects. I have supervised a few senior projects specifically in this field, such as those by Glen Knoch and Katheryn Ross, and non-linear effects show up in some of the acoustical investigations I have mentioned above.

A decade ago, I had a succession of students who have wanted to know more about modern approaches to differential geometry and how these might be applied to General Relativity and other areas of Physics. This entailed a few tutorials in various aspects of differential geometry, with the students and me understanding the important questions and the answers better each time. Some of the senior projects I have supervised in those years have delved into this area as well, such as recasting electromagnetism and mechanics in the language of differentiable manifolds and differential forms (theses by Farasat Bokhari, Eduardo Rozo, and Todd Krause). Maxwell and Einstein taught us that finding the right mathematical language for a problem can help you more easily identify the essential characteristics of a system, and that effort goes on.

Since my graduate school days at Illinois, I have had a long-running interest in the conceptual and philosophical foundations of quantum mechanics. I have had a few senior project students do investigations that touch on this subject: Sebastian Thomson's modeling of barrier tunneling, Rob Cutler's study of the Aharanov-Bohm effect, and Jurvis Lasalle's computer simulation of quantum wave scattering. My library in this area keeps growing as I find yet another piece of the puzzle in a new author's treatment of the puzzles that seem to lie at the heart of sub-atomic physics. Although my colleague Peter Skiff delights in pointing out the naivete of my position, my philosophical heart is that of a realist. As such, I continue to try to understand at many levels what quantum mechanics is telling us about how the world works.

In 1999, I finally got up the nerve to engage a group of students in a coordinated attempt to understand Heisenberg's Uncertainty Principle and other "quantum weirdness". That course, Schrödinger's Cat and All That, has been successful in helping me and my students all clarify what bothers us about quantum physics and where the answers might lie. I find myself convinced that the relatively new theory of Decoherence provides a valid solution to the quantum measurement problem, and I feel that most of the other conceptual problems we face are caused by our attempts to shoehorn phenomena that actually occur into an inappropriate language. I still would like to find a consistent way to determine when a seemingly reasonable question is in fact one that cannot be asked within quantum mechanics.

As is true of most science teachers, I am addicted to problem solving and to explaining things. A few times each semester, something that happens in a class or in working with a student will cause me to think of a better way that a problem can be approached or a topic formulated. So, I write up a fully worked out solution for myself and it goes into my book of notes. Much of this work ends up in later classes or as research ideas for students to explore. I have posted a few of these notes elsewhere on my website.

My physics interests just seem to keep growing as I age, and my library stands as a testament to that. For years, I have been stockpiling science biographies and books written by the 'giants' of old, in order to look at fundamental physics ideas in the context in which they developed them. Reading the original works by Maxwell, Boltzmann, Gibbs, Planck, and others continually gives me a richer understanding of familiar physics topics and the process of doing science.

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