The 2016 Nobel Prize for Physics was a subject of much speculation. The buzz has been all about the LIGO team’s spectacular validation of Einstein’s General Theory of Relativity by finding two instances of black hole merger. But the Nobel is awarded to a maximum of three people and LIGO involved over a thousand scientists.
The Nobel Committee picked something entirely different. One-half of the Nobel Prize in Physics 2016 was awarded to David J Thouless, (82, University of Washington, Seattle) and the other half split between F Duncan M Haldane (65, Princeton) and J Michael Kosterlitz (74, Brown University) “for theoretical discoveries of topological phase transitions and topological phases of matter”. All three are American citizens, who happen to be British by birth.
Their work revolves around topology, the mathematics of geometric and spatial properties. Topology studies properties that stay the same when an object is stretched, twisted or deformed, but not torn. For example, a doughnut with one hole is the same as a coffee cup with a handle, since (assuming it was made from modelling clay), the doughnut could be stretched and squashed into the shape of the coffee cup without tearing. Topology deals in integers; an object may have one hole, or three holes or eight holes, but not 2.7 holes.
These three found topological properties of two-dimensional and one-dimensional structures, which apply in “flatland” physics, on the surfaces of materials can be considered two-dimensional, and on threads so thin that they can be considered one-dimensional.
Condensed matter physics studies materials at very low temperatures. Weird effects like superconductivity, where an electrical current runs forever, and superfluidity where liquids flow upwards are seen. Non-magnetic metals develop magnetic properties.
Phase transitions from gaseous to plasma, to liquid, to solid, and in-between are especially interesting.
More From This Section
Kosterlitz and Thouless worked together to find what is known as the BKT Phase-transition named after the late Vadim Berezinsky, Kosterlitz and Thouless. When for example, ice melts, it forms vortices that move apart. The BKT Transition also works for some areas of atomic physics.
Thouless and Haldane were working separately when they discovered topological explanations for an electrical effect (the “Hall Effect”) where conduction rises in integral steps at very low temperatures. Conductance doubles, triples, or quadruples in exact multiples, if magnetic field and current vary. Topology, with its focus on integers, found explanations for this, which were later experimentally verified. The new understandings developed by this trio have led to a better understanding of quantum effects and condensed matter physics. These may be of great use in designing new types of “super-materials” with unusual properties.
The Nobel Prize in Chemistry 2016 was awarded jointly to Jean-Pierre Sauvage (72, Université de Strasbourg), Sir J Fraser Stoddart (74, Northwestern University) and Bernard L Feringa (65, University of Groningen) “for the design and synthesis of molecular machines”. Nanotechnology, or the building of very small machines, has been a subject of interest since the 1980s when Richard Feynman coined the term.
A machine must, almost by definition, consist of parts that can move in relation to each other. Sauvage worked in photochemistry, developing molecular complexes that capture solar energy. His group built one ring-shaped and one crescent-shaped molecule attracted to a copper ion; the crescent-shaped molecule was bonded with a third molecule to form a link in a chain. The copper ion was then removed. These interlocking rings can be into long chains. In 1994, Sauvage’s group produced a structure where one ring rotated, in a controlled manner, around the other ring when energy was added.
Meanwhile, Stoddart managed to put together structures, which combined electron-rich and electron-poor materials to create moving parts, including nano-lifts and nano-muscles. Feringa found ways to design molecular motors that rotated in controlled fashions. By 2014, Feringa’s motor was revolving at 12 million revolutions per second and he has also built a four-wheel nano-car. Molecular motors can now grasp and connect amino acid chains.
The potentialities of what could arise from this brand new field are hard to even imagine as yet. These molecular machines are about 1/1,000 of a strand of hair in their dimensions and these are just demonstrations of the many sorts of machines that could exist at this size.