Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: From Satisfying to Violating the Null Energy Condition   We construct a theory which admits a time-dependent solution smoothly
interpolating between a null energy condition (NEC)-satisfying phase at early
times and a NEC-violating phase at late times. We first review earlier attempts
to violate the NEC and an argument of Rubakov, presented in 1305.2614, which
forbids the existence of such interpolating solutions in a single-field
dilation-invariant theory. We then construct a theory which, in addition to
possessing a Poincar\'e-invariant vacuum, does admit such a solution. For a
wide range of parameters, perturbations around this solution are at all times
stable, comfortably subluminal and weakly-coupled. The theory requires us to
explicitly break dilation-invariance, so it is unlikely that the theory is
fully stable under quantum corrections, but we argue that the existence of a
healthy interpolating solution is quantum-mechanically robust.

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The categories of this paper are: cond-mat
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The categories of this paper are: stat
30
The categories of this paper are: q-alg
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The categories of this paper are: eess
36
The categories of this paper are: cmp-lg
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The categories of this paper are: hep-lat
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The categories of this paper are: nucl-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: math
9
The categories of this paper are: nlin
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The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
33
The categories of this paper are: plasm-ph
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The categories of this paper are: funct-an
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The categories of this paper are: chem-ph