more about me
The recent publication of the sixth book of my experimental and theoretical researches, Quantum Superposition: Counterintuitive Consequences of Coherence, Entanglement, and Interference (Springer, 2008) has prompted me to look back over a long career as a physicist and educator. Ever since I was a child, absorbed in the books of George Gamow, James Jeans, Arthur Eddington, and other physicists and astronomers, I have been fascinated by the complexities of physical phenomena and driven to understand their underlying causes. And so, I became a physicist (Ph.D. Harvard University, 1973). Working primarily at academic institutions, I have had the good fortune to be able to choose to research whatever problem I wanted to—and in the course of a long career I have chosen eclectically.
I started out as an atomic physicist, developing a spectroscopic method (which I called SABER for Spectroscopy with Accelerated Beam and Electric Resonance) to study the short-lived quantum states of excited atoms. Using SABER on hydrogen, the simplest atom of the periodic table, I investigated quantum electrodynamics (QED), which provides a theoretical description of all known electromagnetic processes with breathtaking accuracy, as confirmed by experiments such as mine and others of truly awesome precision. Non-physicists might find dull the endeavor to measure some physical quantity to higher and higher precision, but it is the discrepancy between such careful measurement and a powerful physical theory that enables physicists to arrive at the next level of understanding of how the world works. We now know, for example, that QED is but a part of a broader theory that encompasses the weak nuclear interactions in addition to all electromagnetic phenomena.
The physicist who, perhaps more than any other, served as my role model was Nobel Laureate Enrico Fermi, a man as adept with theory as he was at home in the laboratory. Like Fermi, I wanted to be able to do both theoretical and experimental work with equal facility, a combination not commonly encountered in physics. Thus, for example, prior to and during my experiments on the hydrogen atom, I also developed a comprehensive quantum theory of the multi-photon interactions of atoms with radiofrequency and microwave fields. The combined theoretical and experimental work was eventually published as my fourth book, Probing The Atom: Interactions of Coupled States, Fast Beams, and Loose Electrons (Princeton University Press, 2000). The title, a mildly naughty play of words, was inspired by the originally conceived title “Base Pairs” of James Watson’s famous book.
In the years that followed, quantum physics constituted a significant part of my research. I have investigated quantum mechanics with electron interferometry, electron microscopy, radiofrequency and microwave spectroscopy, coherent laser spectroscopy, nuclear magnetic and electron paramagnetic resonance, atomic beams, radioactive nuclei, and of course pencil, paper, and computers. One of the most satisfying experiences of this phase of my career resulted from the time I spent in Japan as the first Western scientist invited to be Chief Researcher at the Hitachi Advanced Research Laboratory near Tokyo. I proposed to the electron microscopy group an experiment to demonstrate the buildup of an electron interference pattern one electron at a time. This two-slit electron interference—which is one of the most dramatic illustrations of the wave-particle duality of nature—was designated in 2002 the “most beautiful experiment in physics” by readers of Physics World, the flagship publication of the Institute of Physics.
I have also worked in other fields, such as physical optics. Using polarized light and a device known as a photoelastic modulator, I devised a method for detecting and imaging hidden objects immersed in scattering media of the opacity of whole milk. The same methodology provided a means for quantitatively observing for the first time the difference with which a chiral substance (i.e. one not superimposable on its mirror image) reflects left- and right-circularly polarized light. Since molecular chirality is the hallmark of the living state, this research provided a powerful new way for exploring systems critical to biology and medicine, as well as to materials science. In another phase of my optics work, I devised a method of point-projection imaging which extracted symmetry patterns from a complex object with high noise content. This method of lensless imaging has great potential for structure determinations by X-ray and neutron diffraction. I described some of my most interesting optics work in my third book, Waves and Grains: Reflections on Light and Learning (Princeton University Press, 1998).
During the past 10 years or so, I have become deeply involved with the very subject matter of the books that first drew me into physics as a child, namely the evolution of the universe, galaxies, and stars. I have been investigating seminal astrophysics problems concerning dark matter, dark energy, and the internal structure of neutron stars and black holes, research I discuss in my most recent books, A Universe of Atoms, An Atom in the Universe (Springer, 2002) and Quantum Superposition. My theoretical solutions to these astrophysics problems are unlikely to be tested experimentally any time soon, but I have no doubt that some day we will know the answers.
One of my greatest pleasures as a physicist is to recognize a significant conceptual problem, work out the theory of it, and then go into my laboratory and test it. There is an unimaginable satisfaction to finding that the esoteric mathematical symbols created in one’s mind and scribbled on a sheet of paper actually foretell accurately what Nature will do.
My career as a physicist has also afforded me the pleasure of numerous close collaborations with colleagues throughout the world. Because of my work as a scientist, my children have grown up as world citizens whose homes have ranged from New Zealand to Finland and throughout the US, Europe, and the Far East. To accommodate this travel, my wife and I undertook the education of our children ourselves, and this homeschooling experience from kindergarten through high school has not only made for close family ties among us, but has also had a profound positive influence on my teaching of university-level science.
If there is one overarching lesson that I have gleaned from my career as a physicist, it is that the universe is governed by comprehensible physical laws. Nothing supernatural is needed at all to make sense of the world. If only this lesson could be inculcated throughout the US school system where, regrettably, creationist attempts to undermine the teaching of science are still all too prevalent.
Trinity's science quad. Left, bottom, and right: Math, Computer Science, and Engineering; Biosciences; and Physics.