Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spectral properties of the 2D Holstein polaron   The two-dimensional Holstein model is studied by means of direct Lanczos
diagonalization preserving the full dynamics and quantum nature of phonons. We
present numerical exact results for the single-particle spectral function, the
polaronic quasiparticle weight, and the optical conductivity. The polaron band
dispersion is derived both from exact diagonalization of small lattices and
analytic calculation of the polaron self-energy.

2
The categories of this paper are: math
1
The categories of this paper are: cs
18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
20
The categories of this paper are: acc-phys