Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Sign of the Casimir-Polder interaction between atoms and oil-water
  interfaces: Subtle dependence on dielectric properties   We demonstrate that Casimir-Polder energies between noble gas atoms
(dissolved in water) and oil-water interfaces are highly surface specific. Both
repulsion (e.g. hexane) and attraction (e.g. glycerine and cyclodecane) is
found with different oils. For several intermediate oils (e.g. hexadecane,
decane, and cyclohexane) both attraction and repulsion can be found in the same
system. Near these oil-water interfaces the interaction is repulsive in the
non-retarded limit and turns attractive at larger distances as retardation
becomes important. These highly surface specific interactions may have a role
to play in biological systems where the surface may be more or less accessible
to dissolved atoms.

28
The categories of this paper are: alg-geom
6
The categories of this paper are: astro-ph
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
33
The categories of this paper are: plasm-ph
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio