Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: $k^+=0$ Modes in Light-Cone Quantization   We investigate the light-cone quantization of $\phi^3$ theory in 1+1
dimensions with a regularization of discretized light-cone momentum $k^+$.
Solving a second-class constraint associated with the $k^+=0$ mode, we show
that the $k^+=0$ mode propagates along the internal lines of Feynman diagrams
in any order of perturbation, hence our theory recovers the Lorentz invariance.

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The categories of this paper are: quant-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: physics
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The categories of this paper are: stat
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The categories of this paper are: econ
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The categories of this paper are: astro-ph
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The categories of this paper are: q-alg
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The categories of this paper are: adap-org
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The categories of this paper are: ao-sci
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The categories of this paper are: math
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The categories of this paper are: cmp-lg
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The categories of this paper are: bayes-an
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The categories of this paper are: cond-mat
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The categories of this paper are: plasm-ph
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The categories of this paper are: q-bio
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The categories of this paper are: solv-int