Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Field Theory Revisited   Following P. A. M. Dirac's critique in ``Lectures on Quantum Field Theory''
of the usual formalism, I will discuss the role of the time parameter to solve
R. Haag's no-go theorem on the non-equivalence of the conventional
Schr\"odinger picture and the Heisenberg picture. This is possible by first
defining in a correct way the concept of the vacuum state at a given time in
relativity. I will also discuss some consequences such as the spectral
condition.

10
The categories of this paper are: q-bio
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
21
The categories of this paper are: adap-org
24
The categories of this paper are: dg-ga
32
The categories of this paper are: atom-ph
18
The categories of this paper are: econ
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The categories of this paper are: alg-geom
11
The categories of this paper are: hep-lat
6
The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an
15
The categories of this paper are: nucl-ex