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Superfluidity, or fluid flow without viscosity, is an intrinsically quantum-mechanical phenomenon, that is, where it occurs, it is intimately connected to the properties of the system at a microscopic, atomic level. Superfluidity is nevertheless associated with some spectacular large-scale effects, most notably in liquid Helium II, where under the right circumstances the fluid can for example flow up the walls and out from a confining vessel. Superfluidity is observable in a variety of physical systems, and is frequently intimately associated with the phenomenon of Bose-Einstein condensation, where, for certain kinds of identical (bosonic) particles, for low enough temperatures a significant fraction of the particles collapse into the same state, from then on in a sense acting as one. The 1995 observation of Bose-Einstein condensation in dilute atomic vapours, for which the 2001 Nobel prize was won by Eric Cornell, Wolfgang Ketterle, and Carl Wieman, thus provided a huge stimulus to the fundamental study of superfluid and related properties. This is in significant part because such dilute vapours are significantly simpler to describe and understand than the much denser systems of liquid Helium or the metals and ceramics in which the related phenomenon of superconductivity is observed. A much more recent, related phenomenon is that of so-called exciton and polariton condensates in semiconductors, with particular interest paid to the properties of the light emitted from such systems.This is an expanding field, with workers on the variety of superfluid and condensation phenomena coming from an equally broad range of scientific backgrounds. There is therefore substantial scope for interdisciplinary cooperation, particularly as a number of seemingly distinct theoretical methodologies, each with its own particular strengths and insights, have been developed independently to describe systems which appear to have many things in common. This applies particularly when attempting a precise description of dynamics (i.e., when the system is no longer at equilibrium), and when the temperature of the system is low, but noticeably greater than absolute zero. For any potential applications, such as in precision measurement of surface forces, time and frequency standards, and even the possible elucidation of gravitational effects beyond those described within Einstein's general theory of relativity, a thorough, predictive understanding of finite temperature in a non-equilibrium configuration will be essential, as well as being of fundamental physical interest. We have therefore chosen to hold the workshop FINESS, which will have an outstanding international roster of leading scientists in their fields in Durham, September 2009. This is a great opportunity for UK physics, notably for junior workers in the field attending the workshop.
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