Thermal Casimir Force

Finite Size Scaling at Criticality

red ballCorrelation lengths diverge at a critical point:

yellow ball Finite-size contribution of long-wavelength fluctuations at criticality:

M.E. Fisher and P.-G. de Gennes, C. R. Acad. Sci. Ser. B 287, 207 (1978)

Colloidal particles in a critical binary mixture

red ball  "Direct measurement of critical Casimir forces,"

Hertlein, Helden, Gambassi, Dietrich & Bechinger, Nature 451, 172 (2008)

     

red ball Depending on boundary conditions, these forces can be attractive or repulsive:

"Critical Casimir forces in colloidal suspensions on chemically patterned surfaces,"

F. Soyka, O. Zvyagolskaya, C. Hertlein, L. Helden, & C. Bechinger, Phys. Rev. Lett. 101, 208301 (2008) (movie)

  

yellow ball Like boundaries attract, unlike boundaries repel.