The Simon Prize
The Low Temperature Group of The Physical Society, which owed so much to Sir Francis Simon, established this award in 1958 in his memory. The award is made by the committee of the IOP Low Temperature Group who are also the trustees.
The award shall be made approximately every three years for distinguished work in experimental or theoretical low temperature physics. The prize is £300 and is accompanied by a certificate and a bronze plaque.
The 2011 Simon Memorial Prize is awarded to Sergey V. Iordanskii and Nikolai B. Kopnin "For their calculations and predictions of the fundamental forces acting on quantised vortices in superfluids, superconductors and other ordered systems: The Iordanskii force and the Kopnin force"
A vortex moving in a classical liquid experiences the famous Magnus force which acts between the liquid and the vortex. However, superfluids and superconductors differ from classical fluids and introduce new forces that were first understood by Kopnin and Iordanski. This physics was later understood to have much wider applicability.
The Iordanskii force arises in both Bose and Fermi superfluids and has a universal form. Its value is fundamental, being determined by the vortex winding number, the density of the normal component and the vortex velocity relative to the normal component. The universality arises from the topological nature, it is the result of the Aharonov-Bohm effect experienced by quasiparticles that are scattered by the vortex. A similar effect occurs in cosmology for matter scattering on spinning cosmic strings.
The Kopnin force appears in BCS systems - superconductors and fermionic superfluids. The Kopnin force is also fundamental. It has the same origin as the Adler-Bell-Jackiw anomaly in relativistic quantum field theories. In the Standard Model of particle physics the anomaly leads to non-conservation of baryonic charge and as a result to an excess of matter over anti-matter in our Universe. In superconductors and fermionic superfluids the same anomaly leads to the apparent non-conservation of momentum, which manifests as the Kopnin force.
The combined Iordanskii and Kopnin forces are also important in many areas of physics. In superconductors, the motion of quantized Abrikosov vortices is the only significant source of dissipation, making the Iordanskii and Kopnin forces of considerable technological importance and in superfluids, the predictions of Iordanskii and Kopnin have led to the discovery of new phenomena. The Iordanskii and Kopnin forces are essential to the understanding of vortex dynamics in neutron and proton superfluids and in the coloursuperconducting quark matter that may exist in the core of a neutron star.
The prize presentation will take place at the 26th International Conference on Low Temperature Physics (LT26), Beijing, August 2011