"International Workshop on the Bogoliubov de Gennes Equations for Superfluids"
Burwalls Centre
University of Bristol, Bristol, UK May 30 - June 1, 2003
The "International Workshop on the Bogoliubov de Gennes Equations for Superfliuds " was held in Bristol over the weekend 30 May- 1 June 2003. The topics covered included applications of the Bogoliubov de Gennes (BdeG) equations to: bulk superconductors, mesoscopic superconductors, Josephson junctions, vortex matter, semiclassical transport theories, and Bose-Einstein condensates. The BdeG equations form a common theoretical framework under which all of these diverse topics in superconductivity and superfluidity can be addressed.
Several talks concerned pairingand transport in mesoscopic superconductors. The talks by V. Falko and M. Krawiec concerned the proximity effect and transport in mesoscopic structures containing both superconducting and ferromagnetic elements. The spin accumulation and spontaneous spin polarized currents predicted for these structures provide interesting novel opportunities for spin manipulation, spin injection and spintronics. M. Eschrig showed that the induced p-wave Cooper pairing near a S/N interface leads to an unusual long-ranged Josephson effect in superconductor-half metal-superconductor trilayers. Other talks on transport concerned weak localization effects at S/F interfaces (McCann) and the fluctuation corrections to thermal conductivity (Smith). Tanaka addressed the electronic states in the presence of superconducting vortices in mesoscopic systems, and Quintanilla discussed anomalous Josephson effects in high T, superconductor junctions.
The theme of semiclassical methods for transport was developed in talks by Gyorffy, Sieber, Cserti and Polniak. Sieber outlined a general theory for quantum transport in chaotic systems, while Gyorffy and Cserti considered the formulation of semiclassical approximations for quasiparticle states in superconductors.
The boson or superfluid analogue of the fermionic Bogoliubov de Gennes equations are the Gross-Pitaevskii equations. The solutions of these equations lead to a number of effects in superfluids and in Bose-Einstein Condensates (BEC). Ruostekoski and Martin discussed the solution of these equations, especially in the presence of periodic optical lattice potentials.
A series of talks on novel superconducting materials included talks on high T, superconductors (Hussey), ZrZn2 (Santi), Sr2Ru04 (Litak) and MgB2 (Gabovich). Hussey presented dramatic new experimental evidence for a fully three dimension]. Fermi surface in the cuprate superconductors, which is in good agreement with band theory predictions. Santi showed that LSDA band calculations give a good basis for understanding both the static ferromagnetism in the weak itinerant magnet ZrZn2, and that the spin fluctuations about this ground state provide a possible route towards understanding the superconductivity in this material. Litak presented a model for the exotic material Sr2Ru04, corresponding to a unique p-wave pairing state, analogous to the A phase of suerfluid 4He. Finally, Gabovich argued that the miutiband models of superconductivity in MgB2 are not consistent with experiments, and instead result from a spatially inhomgenous distribution of local gap values.
A relatively new theme is the application of superconducting devices for possible applications in quantum computing and quantum information. This area was reviewed by Annett, who also discussed the possibility of observing entanglement between two macroscopic superconducting devices. Vourdras considered the further effects that can occur in such superconducting quantum coherent devices when the quantization of external microwave fields is taken into account.
Finally, Moradian presented new results on the density of states for a Ni impurity in a BSCCO high T, superconductor, and its comparison to recent STM experiments by Davis et al..
James F Annett and Balazs L Gyorffy
More details may be found in newsletter 58 from page 87
