David R. NelsonDavid Nelson is Mallinckrodt Professor of Physics and Professor of Applied Physics at Harvard University. He received his Ph.D. in 1975 from Cornell University. His research focuses on collective effects in the physics of condensed matter, particulaly on the interplay between fluctuations, geometry and statistical mechanics. In collaboration with his Harvard colleague, Bertrand I. Halperin, he is responsible for a theory of dislocation- and disclination-mediated melting in two dimensions. The prediction of Halperin and Nelson of a fourth 'hexatic' phase of matter, interposed between the usual solid and liquid phases, has now been confirmed in many experiments on thin films and bulk materials. A member of the National Academy of Sciences, the American Academy of Arts and Sciences and a Fellow of the American Physical Society, David Nelson has been an A. P. Sloan Fellow, a Guggenheim Fellow and a Junior and Senior Fellow in the Harvard Society of Fellows. He is the recipient of a five-year MacArthur Prize Fellowship, the National Academy of Sciences Prize for Initiatives in Research, and the Harvard Ledlie Prize. Read More Read Less