Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cumulant expansion method in the density matrix approach to wave packet
  dynamics in molecular systems   A non-Markovian master equation for a molecule interacting with a heat bath
is obtained using the cumulant expansion method. The equation is applied to the
problem of molecular wave packet relaxtional dynamics. An exact solution is
derived that demonstrates classical type of squeezing for the wave packet
evolution and a heat-bath dependent frequency shift.

25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
19
The categories of this paper are: eess
9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
2
The categories of this paper are: math