Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nonperturbative Vacuum Effect in the Quantum Field Theory of Meson
  Mixing   Replacing the perturbative vacuum by the nonperturbative vacuum, we extend a
recent development of a quantum field theoretic framework for scalar and
pseudoscalar meson mixing. The unitary inequivalence of the Fock space of base
(unmixed) eigenstates and the physical mixed eigenstates is investigated and
the flavor vacuum state structure is explicitly found. This is exploited to
develop formulas for two flavor boson oscillations in systems of arbitrary
boson occupation number. We apply these formulas to analyze the mixing of eta
with eta' and comment on the other meson-mixing systems. In addition, we
consider the mixing of boson coherent states, which may have future
applications in the construction of meson lasers.

11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
26
The categories of this paper are: bayes-an
33
The categories of this paper are: plasm-ph
27
The categories of this paper are: comp-gas
2
The categories of this paper are: math
18
The categories of this paper are: econ
29
The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
31
The categories of this paper are: ao-sci