2 December, 2021
The Frontiers committee recognized Fisher for his “fundamental contributions” to statistical mechanics, the branch of physics that studies how molecules behave en masse rather than individually. This “crowd” behavior intervenes in a phenomenon that enthralled Fisher: phase transitions, those critical moments when matter moves from one state to another: “Our lives rely on the fact that the air is easy to breathe and the water is easy to drink, but we know that water will freeze if it gets too cold and boil if it gets too hot, so we are familiar with the fact that everyday matter can change from one form to another. And we have to understand those changes,” he explained in an interview granted just a few hours after hearing of the Frontiers award.
Fisher’s research showed that the theory of phase transitions in place for over a century was in fact wrong; not only did he correct it, he also realized that his model could serve for many different systems. His insights contributed to a deeper understanding of processes like the evaporation or freezing of water, but also why a metal becomes magnetized or turns into a superconductor.
In the words of the committee: “his work helps to interpret the vast diversity of the behaviors of bulk matter in terms of the characteristics of the component atomic or molecular parts and their interactions.”
“There comes a point where there is no difference between liquid and vapor, but why exactly?”
“When I put a lot of molecules of water together, why do many of them freeze? And, most surprising, if I enclose them in a container and raise the pressure and the temperature, there will come a critical point above which the difference between liquid and vapor disappears; the water becomes dense but there is no interphase. Why does this happen? What exactly is going on in the vicinity of the interphase?” Fisher pondered. “Where one state of matter changes into another there is a very special point that has fascinated me for years.”
The interdisciplinary Fisher – professor of Physics, Chemistry and Mathematics – made his final contributions in biology, which increasingly engrossed him: “Every cell is like a whole, fascinating little city,” he enthused.
In the city-cell “you can start in politics, for instance, and there are all those things you have to worry about, like transportation or water supply,” he explained. “In biology, you can conduct all kinds of incredible experiments, like hook a tag onto that molecule and see how it moves around within the cell. But how does it move? How does the molecule do it? The theory you need to answer these questions is also statistical mechanics.”
Michael E. Fisher (Trinidad and Tobago, 1931, of British nationality) earned his PhD in Physics in 1957 from King’s College London, where he was appointed lecturer in 1965. The following year, he moved to Cornell University University (United States) where he was successively Professor of Chemistry and Mathematics (1966-1973) and Horace White Professor of Chemistry, Physics and Mathematics (1973-1989), as well as chairing the Department of Chemistry from 1975 to 1978. In 1971, he was elected a member of the Royal Society and in 1983, of the U.S. National Academy of Sciences. He joined the Institute for Physical Science and Technology at the University of Maryland in 1987.
Besides the BBVA Foundation Frontiers of Knowledge Award, Fisher’s many distinctions include the Wolf Prize (in 1980, jointly with Kenneth G. Wilson and Leo Kadanoff), the Irving Langmuir Prize in Chemical Physics (1971), the Boltzmann Medal of the International Union of Pure and Applied Physics (1983), the Lars Onsager Prize of the American Physical Society (1995) and the Royal Medal in Physics of the UK’s Royal Society (2005).