Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Diffuse approximation to the kinetic theory in a Fermi system   We suggest the diffuse approach to the relaxation processes within the
kinetic theory for the Wigner distribution function. The diffusion and drift
coefficients are evaluated taking into consideration the interparticle
collisions on the distorted Fermi surface. Using the finite range interaction,
we show that the momentum dependence of the diffuse coefficient $D_{p}(p)$ has
a maximum at Fermi momentum $p=p_{F}$ whereas the drift coefficient $K_{p}(p)$
is negative and reaches a minimum at $p\approx p_{F}$. For a cold Fermi system
the diffusion coefficient takes the non-zero value which is caused by the
relaxation on the distorted Fermi-surface at temperature $T=0$. The numerical
solution of the diffusion equation was performed for the particle-hole
excitation in a nucleus with $A=16$. The evaluated relaxation time
$\tau_{r}\approx 8.3\cdot 10^{-23}\mathrm{s}$ is close to the corresponding
result in a nuclear Fermi-liquid obtained within the kinetic theory.

11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph
21
The categories of this paper are: adap-org
3
The categories of this paper are: physics
27
The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph