Quantum Magnetism - the LEGO of physics – Niels Bohr Institute - University of Copenhagen

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Quantum Magnetism - the LEGO of physics

One of the most general problems in physics is how to deal with many
interacting objects - be it stars in a galaxy or nerve-cells in a brain. The
particular question of how quantum mechanics allow simultaneous coexistence of
different configurations of these objects - entanglement - is of increasing
technological importance, as a limit to current electronics and as a prospect
for future 'quantum computation'. In this seminar, I will explain how crystal
assemblies of atomic magnetic moments - Quantum Magnets - combined with
powerful experimental techniques form an ideal arena in which to develop our
understanding and control of the quantum many-body problem. As an example, I
will show how the simple two-dimensional quantum Heisenberg antiferromagnet
appear classical on long time and length scales, but reveals it quantum nature
on atomic distances, indicating the formation of so-called resonating valence
bonds, which might in turn be the key to understanding high-temperature
superconductivity - an outstanding problem in contemporary condensed matter