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Novel States of Quantum Order

When large numbers of atoms or electrons in a solid interact, their local quantum mechanics can be very complex. But sometimes strikingly simple collective properties appear, such as magnetism or superconductivity. These properties cannot exist for single atoms, or even small collections of them: they emerge at a higher level. Understanding this emergence is a central issue of modern physics, whose global pursuit has led to many Nobel prizes, most recently Anthony J Leggett FRS of the University of Urbana Champaign. Quantum ordering is also an industrially significant area: digital storage media, medical imaging, etc. are all based on magnetism (and often require superconductivity also). New emergent phenomena, as yet undiscovered, may spawn the IT industries of tomorrow.

Within SUPA the main strengths in superconductivity and magnetism are at St Andrews, Glasgow and Edinburgh with smaller units at Heriot Watt and Strathclyde. SUPA is affiliated to ICAM, an international forum for researchers into emergent phenomena.

The experimentally determined "Fermi surface" of an oxide metal (Sr2RuO4) whose electrons condense into an entirely novel superconducting state whose properties were partially predicted by some of Leggett’s classic work. (Image: A. MacKenzie. St Andrews.)