Lawrence H. Bennett
George Washington University , USA
Title: Bose-Einstein condensation
Lawrence H Bennett has been a Research Professor at the Institute for Magnetics Research, School of Engineering and Applied Science, The George Washington University, USA since 1996. He received a BA in Physics and Mathematics from Brooklyn College in 1951, a MS in Physics and Electrical Engineering from the University of Maryland in 1955, and a PhD in Physics from Rutgers University in 1958. He retired from the National Institute of Standards and Technology as a Senior Scientist. From 1959 – 1990 he was Adjunct Professor of Physics at the University of Maryland. He is a Fellow, American Physical Society (Past Chair, Topical Group: Magnetism and Applications) Fellow, American Society for Metals Senior Member, IEEE Magnetics Society (Past Chair, Washington Chapter) The Metallurgical Society (Past Chair: Committee on Alloy Phases) Materials Research Society (Past member: Nominating and Finance Committees; Chair of International Committee for HMM (Hysteresis and Micromagnetic Modeling). He is author or coauthor of almost 400 papers.
The occupation of a single quantum state by a large fraction of bosons at low temperatures was predicted by Bose and Einstein ninety years ago. The theory of Bose-Einstein condensation (BEC) of atoms is now well accepted, following on ingenious experiments, on dilute ultracold gases of atoms, with many laboratories showing new effects. In direct contrast, the occurrence of BEC in quasiparticles (magnons, excitons, polaritons, etc.) has raised many heated discussions, and very different opinions have been expressed about its nature. Snoke has presented criteria for excitons he believes are needed to qualify as a BEC. With magnons, Bunkov and Volovik do not accept the claim of the observation of BEC of magnons, whether in antiferromagnetic insulators (ladder compounds), or in pumping experiments, or confined in nanoparticles. Mills has explicitly objected to the appearance of BEC in ladder compounds. It took many years for physicists to accept London’s argument that superfluidity is a BEC phenomenon. P. Anderson noted that “Fritz London’s single-minded thinking led him to surpass even Einstein, as he believed correctly that quantum mechanics was right at all scales, including the macroscopic.”