Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Terahertz radiation-induced sub-cycle field electron emission across a
  split-gap dipole antenna   We use intense terahertz pulses to excite the resonant mode (0.6 THz) of a
micro-fabricated dipole antenna with a vacuum gap. The dipole antenna structure
enhances the peak amplitude of the in-gap THz electric field by a factor of
~170. Above an in-gap E-field threshold amplitude of ~10 MVcm-1, THz-induced
field electron emission is observed (TIFEE) as indicated by the field-induced
electric current across the dipole antenna gap. Field emission occurs within a
fraction of the driving THz period. Our analysis of the current (I) and
incident electric field (E) is in agreement with a Millikan-Lauritsen analysis
where log (I) exhibits a linear dependence on 1/E. Numerical estimates indicate
that the electrons are accelerated to a value of approximately one tenth of the
speed of light.

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The categories of this paper are: quant-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: alg-geom
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The categories of this paper are: dg-ga
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The categories of this paper are: patt-sol
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The categories of this paper are: atom-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: solv-int
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The categories of this paper are: nlin
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-fin
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The categories of this paper are: supr-con
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The categories of this paper are: hep-ex
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The categories of this paper are: astro-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-th