Improvisation on the theme: Dimer motion on a periodic substrate
by
Ralf Eichhorn(Nordita)
→
Europe/Stockholm
122:026
122:026
Description
We consider two coupled particles moving along a periodic substrate potential with negligible inertia effects
(overdamped limit). Even when the particles are identical and the substrate spatially symmetric, a sinusoidal
external driving of appropriate amplitude and frequency may lead to spontaneous symmetry breaking in the form
of a permanent directed motion of the dimer. Thermal noise restores ergodicity and thus zero net velocity, but
entails arbitrarily fast diffusion of the dimer for sufficiently weak noise. Moreover, upon application of a static
bias force, the dimer exhibits a motion opposite to that force (absolute negative mobility). The key requirement
for all these effects is a nonconvex interaction potential of the two particles.
