Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Almost zero-dimensional PT-symmetric quantum field theories   In 1992 Bender, Boettcher, and Lipatov proposed in two papers a new and
unusual nonperturbative calculational tool in quantum field theory. The
objective was to expand the Green's functions of the quantum field theory as
Taylor series in powers of the space-time dimension D. In particular, the
vacuum energy for a massless \phi^{2N} (N=1,2,3,...) quantum field theory was
studied. The first two Taylor coefficients in this dimensional expansion were
calculated {\it exactly} and a set of graphical rules were devised that could
be used to calculate approximately the higher coefficients in the series. This
approach is mathematically valid and gives accurate results, but it has not
been actively pursued and investigated. Subsequently, in 1998 Bender and
Boettcher discovered that PT-symmetric quantum-mechanical Hamiltonians of the
form H=p^2+x^2(ix)^\epsilon, where \epsilon\geq0, have real spectra. These new
kinds of complex non-Dirac-Hermitian Hamiltonians define physically acceptable
quantum-mechanical theories. This result in quantum mechanics suggests that the
corresponding non-Dirac-Hermitian D-dimensional \phi^2(i\phi)^\epsilon quantum
field theories might also have real spectra. To examine this hypothesis, we
return to the technique devised in 1992 and in this paper we calculate the
first two coefficients in the dimensional expansion of the ground-state energy
of this complex non-Dirac-Hermitian quantum field theory. We show that to first
order in this dimensional approximation the ground-state energy is indeed real
for \epsilon\geq0.

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The categories of this paper are: acc-phys
6
The categories of this paper are: astro-ph
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
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The categories of this paper are: nucl-ex
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The categories of this paper are: patt-sol
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The categories of this paper are: ao-sci
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The categories of this paper are: eess
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The categories of this paper are: q-fin
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The categories of this paper are: atom-ph
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The categories of this paper are: q-alg
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The categories of this paper are: nucl-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: alg-geom