Dmitry A. Garanin - Research
Awardee speech at the Faculty Recognition Award luncheon on 5 May 2010
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I would like to thank the Committee for the Faculty Recognition Award in
Research and my colleagues at the Physics Department for the nomination. My research is in the area of theoretical solid-state physics and magnetism. A lot is being done in collaboration with professor Eugene Chudnovsky with whom and our students we form the very active solid-state group at Lehman College. Our main topic for many years has been very small magnetic particles, the so-called nanoparticles, down to magnetic clusters and even to magnetic molecules. These tiny magnets demonstrate quantum-mechanical properties and they can change their orientation (up-down) by tunneling under the barrier that prevents their classical rotation. This effect was first observed by the Myriam Sarachik group at the City College. Together with our theoretical work this created a hot topic and gave rise to a very active International research community. To justify funding our research, we always speak about small magnetic particles as units of memory storage and, more recently, as prospective elements for quantum computing. The most spectacular finding of recent years was magnetic burning that is similar to usual (chemical) burning and was experimentally observed at the City College in 2005. In the burning, or deflagration, the energy stored in the active substance is released as heat that ignites other portions of the active substance. There are burning fronts moving with a well-defined speed. To get an idea of a burning front, you can ignite a piece of paper and look at how the burning front moves. Importantly, magnetic deflagration is non-destructive and experiments can be done on the same crystal many times. The particular mechanism of burning can be different. For instance, one can align dominoes standing on the top, so that a falling domino pushes its neighbor. The resulting process of the destruction of the initial state is nothing else than burning, in a broad sense, and it develops as propagation of a burning front, the front of falling dominoes. In contrast to the standard burning, this process is non-thermal. Since the discovery of magnetic burning, we were thinking of a possibility of a more exotic quantum burning in systems of small magnetic particles. The mechanism of quantum burning that occurs in the form of propagating fronts of tunneling, has been found theoretically and published in a series of papers by our group. Quantum burning is a non-thermal process. Currently at least two experimental groups, at the City College and at the University of Barcelona, are hunting for this effect. Yesterday the latest paper on the subject, co-authored with our PhD student Reem Jaafar, has been published in the Physical Review B as a Rapid Communication. BTW, another our paper with Reem Jaafar on another topic, previously published in Europhysics Letters, has been chosen for the presentation to the general audience in the Europhysics News. Now I think it is enough about physics. More information can be obtained from my Lehman web site. It is time to say a couple of general words. My career as a physicist spans three decades and three countries: Russia, Germany, and the USA. Although I am Lehman professor since 2005, my collaboration with Lehman College dates back to 1996. This is nearly a half of my scientific career and a half of my more than 100 publications. At least the amount of research probably makes today's award deserved. I must add that, although I was actively working and publishing in Russia and Germany, I have never received official recognition in these countries. Maybe this is one of the cultural differences between the Old and New Worlds, and a pleasant one, from my current perspective.
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