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Stable suspension and dispersion-induced transitions from repulsive Casimir forces between fluid-separated eccentric
Alejandro W Rodriguez1, J N Munday, J D Joannopoulos
1Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Abstract:
We numerically demonstrate a stable mechanical suspension of a silica cylinder within a metallic cylinder separated by ethanol, via a repulsive Casimir force between the silica and the metal. We investigate cylinders with both circular and square cross sections, and show that the latter exhibit a stable orientation as well as a stable position, via a method to compute Casimir torques for finite objects. Furthermore, the stable orientation of the square cylinder undergoes a 45 degrees transition as the separation length scale is varied, which is explained as a consequence of material dispersion.
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The motion of the liquid within this infinitesimal cylinder is considered to obtain the pressure difference. Three vertical forces act on this liquid: