Colloquium: November 27, 2013
The universal force of critical fluctuations:
Casimir, wetting, colloids and all that.
|November 27, 2013 Wednesday||16:00||EE01|
ABSTRACT — In 1948, Hendrik Casimir predicted that two uncharged conducting surfaces in vacuum attract each other due to the quantum fluctuations of the electromagnetic field which are spatially confined by these surfaces. The classical analogue of this effect originates from the confinement of thermal fluctuations in fluids near continuous phase transitions, such as the demixing of a mixture of two liquids or the normal-superfluid transition in 4He, and it was first investigated theoretically by Michael Fisher and Pierre-Gilles de Gennes in 1978. Early indirect experimental evidence of the force of these fluctuations – known as critical Casimir force – were provided by detailed studies of complete wetting films. Its first direct measurement at the sub-micrometer scale, instead, was done only in 2008 by monitoring the Brownian motion of a colloidal particle close to a surface, both immersed in a near-critical liquid mixture.
I will present recent advances in the theoretical and experimental study of the universal properties of this novel fluctuation-induced force, discussing in particular its non-equilibrium behavior and possible relevant applications to soft matter systems.
*SISSA and INFN, Trieste, Italy
The Physics Colloquia are designed to address a non-specialist, broad audience and introduce topics of contemporary research through lectures by leading experts. We warmly invite all members of the student body, including undergraduates enrolled in any programme.