Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Behavior of the impurity atom in a weakly-interacting Bose gas   We studied the properties of a single impurity atom immersed in a dilute Bose
condensate at low temperatures. In particular, we perturbatively obtained the
momentum dependence of the impurity spectrum and damping. By means of the
Brillouin-Wigner perturbation theory we also calculated the self-energy both
for attractive and repulsive polaron in the long-wavelength limit. The
stability problem of the impurity atom in a weakly-interacting Bose gas is also
examined.

35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
17
The categories of this paper are: q-fin
30
The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
23
The categories of this paper are: solv-int
3
The categories of this paper are: physics