Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Fluctuations in a diffusive medium with gain   We present a stochastic model for amplifying, diffusive media like, for
instance, random lasers. Starting from a simple random-walk model, we derive a
stochastic partial differential equation for the energy field with contains a
multiplicative random-advection term yielding intermittency and power-law
distributions of the field itself. Dimensional analysis indicate that such
features are more likely to be observed for small enough samples and in lower
spatial dimensions.

31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
25
The categories of this paper are: patt-sol
15
The categories of this paper are: nucl-ex
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
33
The categories of this paper are: plasm-ph
6
The categories of this paper are: astro-ph
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th