Héctor Mancini, Professor Emeritus of the School of Sciences of the University of Navarra
Nobel Prize in Materials Physics
This year the Royal Swedish Academy has decided to award the award Nobel Prize in Physics to three physicists of British origin who pursued their careers at American universities: David Thouless, Professor Emeritus of the University of Washington, Seattle, Duncan M. Haldane, Princeton University, New Jersey, and Michael Kosterlitz of Brown University, Providence, Rhode Island, USA.
The justification of award alludes to "the theoretical discoveries of topological phase transitions and topological phases of the subject". And he comments that the laureates "have opened the doors to an unknown world where the subject can assume strange states" and "have used advanced mathematical methods to study unusual phases and states of the subject such as superfluidity, superconductivity or magnetic states in very thin films".".
At other times the award-winning topic seems more familiar because there is a stream of scientific knowledge dissemination preceding it, this time, it seems to require some clarification for non-experts.
First of all, we speak of "theoretical discoveries", i.e. applications of mathematical concepts or methods, in this case "topological", to physical problems previously studied with other calculus tools. The three prize winners share the use of this new mathematical approach to pre-existing problems. Thus, in the 1970s, Kosterlitz and Thouless demonstrated using topological tools that phenomena such as superfluidity or superconductivity at leave temperature could not occur in thin films; and the mechanism by which superconductivity should disappear at temperatures above a critical value. That is, it underwent a phase transition (like the transition from ice to water).
A decade later Thouless manages to explain an experiment on very thin electrical layers, in which the electrical conductivity measurements gave discrete results (integer steps). He managed to show that these integers were due to the topological nature of the problem. Also around this time, Haldane discovered new applications of topological concepts to small magnet strings. Many of his theoretical predictions were later verified in experiments and these topological methods are now applied not only to thin films or long chains of magnets, but also to three-dimensional materials.
This year the Swedish Academy awarded a prize to a theoretical contribution to the theoretical foundations of techniques of contemporary use in Materials Science. Considering the ages of the awardees (82, 65 and 73 years), we appreciate that the award has been given more to the founders of a school of thought, than to the protagonists of a brilliant one-off event. The applications of their contributions unfold over several decades and are projected into the future as speculation, for example, in future quantum computers.