Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Asymptotic form of the approach to equilibrium in reversible
  recombination reactions   The reversible reactions A+A<=>C and A+B<=>C are investigated. From the exact
Langevin equations describing our model, we set up a systematic approximation
scheme to compute the approach of the density of C particles to its equilibrium
value. We show that for sufficiently long time t, this approach takes the form
of a power law At^(-d/2), for any dimension d. The amplitude A is also computed
exactly, but is expected to be model dependent. For uncorrelated initial
conditions, the C density turns out to be a monotonic time function. The cases
of correlated initial conditions and unequal diffusion constants are
investigated as well. In the former, correlations may break the monotonicity of
the density or in some special cases they may change the long time behavior.
For the latter, the power law remains valid, only the amplitude changes, even
in the extreme case of immobile C particles. We also consider the case of
segregated initial condition for which a reaction front is observed, and
confirm that its width is governed by mean-field exponent in any dimension.

17
The categories of this paper are: q-fin
30
The categories of this paper are: q-alg
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
23
The categories of this paper are: solv-int
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
0
The categories of this paper are: hep-ph
14
The categories of this paper are: math-ph
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc