Cosmos Editorial
The Nobel Prize in Physics 2016 was awarded to physicists in the US who used advanced mathematical methods to explain strange phenomena in unusual phases (or states) of matter, such as superconductors, superfluids or thin magnetic films.
David J. Thouless at the University of Washington received one half of the prize, with the other half shared between F. Duncan M. Haldane and Princeton University and J. Michael Kosterlitz at Brown University.
Kosterlitz and Thouless studied phenomena that arise in a flat world – on surfaces or inside extremely thin layers that can be considered two-dimensional, compared to the three dimensions (length, width and height) we’re used to.
Haldane studied matter that forms threads so thin they can be considered just one-dimensional.
Thanks to their pioneering work, the hunt is now on for new and exotic phases of matter. Many people are hopeful of future applications in materials science and electronics, even quantum computing.
What the winners have in common is they used topology – a branch of mathematics that describes properties that only change step-wise.
In the early 1970s, Kosterlitz and Thouless overturned the then current theory that superconductivity or suprafluidity was not possible in thin layers.
They showed that superconductivity could, in fact, take place at low temperatures and also explained the mechanism – phase transition – that makes superconductivity disappear at higher temperatures.
The leading role in a topological transition is played by small vortices in the flat material.
At low temperatures they form tight pairs. When the temperature rises, a phase transition takes place: the vortices suddenly move away from each other and sail off in the material on their own.
In the 1980s, Thouless explained a previous experiment where he precisely measured the conductance of very thin electrically conducting layers as integer steps, then went on to show that these integers were topological in nature.
Around the same time, Haldane discovered how topological concepts can be used to understand the properties of chains of small magnets found in some materials.
We now know of many topological phases, not only in thin layers and threads, but also in ordinary 3-D materials.
Over the past decade, this area has boosted frontline research in condensed matter physics, not least because of the hope that topological materials could be used in new generations of electronics and superconductors, or in future quantum computers.
