Giovedi' 14 Aprile, ore 16:00 (Aula Caldirola)

Speaker: Andrea Gambassi (Sissa, Trieste)

Title: The critical Casimir effect: thermal fluctuations in action.

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. Early indirect experimental 
evidence of the force of these fluctuations - the so-called critical 
Casimir  force - were provided by detailed studies of complete wetting 
films.
Thirty years after its first  theoretical investigation by Michael 
Fisher and Pierre-Gilles de Gennes in 1978, the critical Casimir force 
has now been measured directly at the sub-micrometer scale 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 possible relevant applications for manipulating soft matter 
systems.