Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gibbs paradox and a possible mechanism of like-charge attraction in
  colloids   Based on a reconsideration of the Gibbs paradox, we show that a residual,
non-extensive term in entropy turns up upon mixing identical particles, whether
they are indistinguishable or not. The positive contribution from this residual
entropy leads to a decrease in free energy, and we suggest that this entropic
mechanism may serve as a source of like-charge attractions between a pair of
colloidal particles or other macroions. For a system of two colloidal particles
along with their neutralizing counterions, such decrease in free energy is of a
few thermal energies and therefore crucial to the effective interaction between
the particles.

34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
27
The categories of this paper are: comp-gas
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
15
The categories of this paper are: nucl-ex
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an
29
The categories of this paper are: funct-an