J.E. Avron, O. Gat, O. Kenneth and U. Sivan
Optimal rotations of deformable bodies and orbits in magnetic fields
(384K, RevTeX 4 with 4 eps figures, and multi-frame gif animation)
ABSTRACT. Deformations can induce rotation with zero angular momentum where
dissipation is a natural ``cost function''. This gives rise to an
optimization problem of finding the most effective rotation with
zero angular momentum. For certain plastic and viscous media in
two dimensions the optimal path is the orbit of a charged particle
on a surface of constant negative curvature with magnetic field
whose total flux is half a quantum unit.