Why 'strange' matter matters to the Nobel Prize committee
On Tuesday, members of the Royal Swedish Academy of Sciences convened in Stockholm to present the Nobel Prize in Physics. The crowd favorite? MIT鈥檚 Laser Interferometer Gravitational-Wave Observatory (LIGO) collaboration, which identified gravitational waves from merging black holes, thus confirming Einstein鈥檚 theory of general relativity.
But LIGO didn鈥檛 take home the Nobel. Instead, the prize went to three British physicists working in a decidedly less flashy field of study: condensed-matter physics.
The winners 鈥� David Thouless, Duncan Haldane, and John Michael Kosterlitz 鈥� have spent much of their careers studying 鈥渟trange鈥� phases of matter. Using a branch of mathematics called topology, they demonstrated why these materials exhibit unusual properties. It鈥檚 important work, but Einstein and black holes are a winning combination in the court of public opinion. So why does matter, well, matter so much to the Nobel committee?
Topology refers to property changes that can only occur in whole steps. A piece of聽Swiss聽cheese, for example, can have any number of holes. But there鈥檚 no such thing as a half hole, so the measurement of holes in cheese can be only an integer.
This year鈥檚 laureates discovered that the properties of strange-matter materials can be measured the same way. In the 1970s, Dr. Kosterlitz and Dr. Thouless demonstrated that very thin materials, when cooled, could undergo 鈥減hase transition鈥� to become superconductive. Just like the聽Swiss聽cheese, the electrical conductivity of the material would only change by integers.
Dr. Haldane applied the same concept to theoretical studies of magnetic atom chains.
鈥淭his matter is topologically different than regular matter, which means it can't be continuously changed,鈥� Haldane said in a press conference. 鈥淭his gives rise to some unexpected properties on the surface of these materials.鈥�
When they were originally published, these studies were valued mostly for their theoretical input. But in recent years, practical uses have begun to emerge.
Quantum condensates can be created by聽super-cooling聽a material beyond its solid state. By creating controlled topological defects (i.e. 鈥渉oles鈥�) in these materials, researchers could induce certain quantum mechanical effects. Some experts say these and other material properties could lead to breakthroughs in quantum computing.
鈥淭his whole field has burgeoned, and this new way of thinking has led to even more discoveries,鈥� Haldane said. 鈥淲hatever the future will bring ... we鈥檝e gone a long way.鈥�
Just how far? Let鈥檚 start at the beginning.
The idea of matter can be found deep within the annals of western philosophy. Hundreds of years before Socrates was born, ancient Greek philosophers toyed with the notion that everything is made of fundamental parts. Some postulated that water was the basic element found in every physical thing; Others believed that the distinction belonged to air or fire.
In the 5th century BC, Democritus argued that all materials consisted of tiny, indivisible particles called 鈥渁toms,鈥� floating in a void. The philosophy of atomism may have actually originated a century earlier in the ancient Indian schools of materialism, but that debate has yet to be resolved. Despite sharing a name, these atoms weren鈥檛 much like the elemental particles we know today 鈥� they came in an infinite number of shapes and sizes and had no internal structure.
Aristotle later argued that matter, or 鈥渉yle,鈥� was directly related to change. In his view, matter was an underlying principle, rather than a physical substance. Imagine eating an apple: After you鈥檝e finished chowing down, your body will retain the apple. But not the whole fruit 鈥� just some aspect of it, the part that Aristotle called matter. This may seem obvious now, but it was a revolutionary concept at the time.
Nearly 2,000 years later, Ren茅 Descartes and Isaac Newton began to assign mathematical concepts, such as inertia and gravity, to the physical properties of matter. This set off a new surge of scientific discovery. In 1897, J.J. Thompson discovered the first subatomic particle: the electron. Physicists later identified new phases of matter 鈥� superfluids, condensates, Quantum Hall states, photonic matter, and more 鈥� beyond the fundamental solids, liquids, gases, and plasmas.
Quantum mechanics, the set of rules which govern the entire universe on the subatomic scale, emerged a few years later. And that鈥檚 where the story of three British physicists really begins.
