Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum Dissipation and Decay in Medium   Quantum dissipation in thermal environment is investigated, using the path
integral approach. The reduced density matrix of the harmonic oscillator system
coupled to thermal bath of oscillators is derived for arbitrary spectrum of
bath oscillators. Time evolution and the end point of two-body decay of
unstable particles is then elucidated: After early transient times unstable
particles undergo the exponential decay, followed by the power law decay and
finally ending in a mixed state of residual particles containing contributions
from both on and off the mass shell, whose abundance does not suffer from the
Boltzmann suppression.

32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph
2
The categories of this paper are: math
28
The categories of this paper are: alg-geom
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci