Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the Spectral Analysis of Quantum Electrodynamics with Spatial
  Cutoffs. I   In this paper, we consider the spectrum of a model in quantum electrodynamics
with a spatial cutoff. It is proven that (1) the Hamiltonian is self-adjoint;
  (2) under the infrared regularity condition, the Hamiltonian has a unique
ground state for sufficiently small values of coupling constants. The spectral
scattering theory is studied as well and it is shown that asymptotic fields
exist and the spectral gap is closed.

6
The categories of this paper are: astro-ph
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
18
The categories of this paper are: econ
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
28
The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex