Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Flux reversal in a two-state symmetric optical thermal ratchet   A Brownian particle's random motions can be rectified by a periodic potential
energy landscape that alternates between two states, even if both states are
spatially symmetric. If the two states differ only by a discrete translation,
the direction of the ratchet-driven current can be reversed by changing their
relative durations. We experimentally demonstrate flux reversal in a symmetric
two-state ratchet by tracking the motions of colloidal spheres moving through
large arrays of discrete potential energy wells created with dynamic
holographic optical tweezers. The model's simplicity and high degree of
symmetry suggest possible applications in molecular-scale motors.

23
The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
2
The categories of this paper are: math
5
The categories of this paper are: gr-qc