Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Deterministic ratchet from stationary light fields   Ratchets are dynamic systems where particle transport is induced by
zero-average forces due to the interplay between nonlinearity and asymmetry.
Generally, they rely on the effect of a strong external driving. We show that
stationary optical lattices can be designed to generate particle flow in one
direction while requiring neither noise nor driving. Such optical fields must
be arranged to yield a combination of conservative (dipole) and nonconservative
(radiation pressure) forces. Under strong friction all paths converge to a
discrete set of limit periodic trajectories flowing in the same direction.

6
The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
2
The categories of this paper are: math
1
The categories of this paper are: cs
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
18
The categories of this paper are: econ
36
The categories of this paper are: cmp-lg
24
The categories of this paper are: dg-ga
32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex