Quantum mechanical tunnelling

Quantum tunnelling refers to the quantum mechanical phenomenon where a particle tunnels through a barrier that it classically could not surmount. This plays an essential role in several physical phenomena, such as the nuclear fusion. It has important applications to modern devices such as the tunnel diode, quantum computing, and the scanning tunnelling microscope. The effect was predicted in the early 20th century and its acceptance as a general physical phenomenon came mid-century.

Tunnelling is often explained using the Heisenberg uncertainty principle and the wave–particle duality of matter. Pure quantum mechanical concepts are central to the phenomenon, so quantum tunnelling is one of the novel implications of quantum mechanics.
K A Solaman

Nobel Prize Physics 2016

Nobel Physics Prize Awarded to 3 for Topology Work

British scientists David Thouless, Duncan Haldane and Michael Kosterlitz won the Nobel Physics Prize today for revealing the secrets of exotic matter, the Nobel jury said. "This year's laureates opened the door on an unknown world where matter can assume strange states.

They have used advanced mathematical methods to study unusual phases, or states, of matter, such as superconductors, superfluids or thin magnetic films. Thanks to their pioneering work, the hunt is now on for new and exotic phases of matter," it said. The laureates will share the eight million Swedish kronor (around USD 931,000) prize sum. Thouless won one-half of the prize, while Haldane and Hosterlitz share the other half. The jury said their pioneering work "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." Topology, in which the three laureates specialise, is a branch of mathematics that investigates physical properties of matter and space that remain unchanged under deforming forces, including stretching.

It holds exceptional promise for quantum computing and tiny quantum devices as topological states can transport energy and information without overheating, unlike traditional quantum mechanics. "They demonstrated that superconductivity could occur at low temperatures and also explained the mechanism, phase transition, that makes superconductivity disappear at higher temperatures," the jury noted.

In the 1980s, Thouless was able to explain a previous experiment with very thin electrically conducting layers in which conductance was precisely measured as integer steps. "He showed that these integers were topological in their nature. At around the same time, Duncan Haldane discovered how topological concepts can be used to understand the properties of chains of small magnets found in some materials."