Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Excitation dynamics in a lattice Bose gas within the time-dependent
  Gutzwiller mean-field approach   The dynamics of the collective excitations of a lattice Bose gas at zero
temperature is systematically investigated using the time-dependent Gutzwiller
mean-field approach. The excitation modes are determined within the framework
of the linear-response theory as solutions of the generalized Bogoliubov-de
Gennes equations valid in the superfluid and Mott-insulator phases at arbitrary
values of parameters. The expression for the sound velocity derived in this
approach coincides with the hydrodynamic relation. We calculate the transition
amplitudes for the excitations in the Bragg scattering process and show that
the higher excitation modes give significant contributions. We simulate the
dynamics of the density perturbations and show that their propagation velocity
in the limit of week perturbation is satisfactorily described by the
predictions of the linear-response analysis.

2
The categories of this paper are: math
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
27
The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex