Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Time-Delayed Magnetic Control and Narrowing of X-Ray frequency Spectra
  in Two-Target Nuclear Forward Scattering   Controlling and narrowing x-ray frequency spectra in magnetically perturbed
two-target nuclear forward scattering is theoretically studied. We show that
different hard-x-ray spectral redistributions can be achieved by single or
multiple switching of magnetic field in nuclear targets. Our scheme can
generate x-ray spectral lines with tenfold intensity enhancement and spectral
width narrower than four times the nuclear natural linewidth. The present
results pave the way towards a brighter and flexible x-ray source for precision
spectroscopy of nuclear resonances using modern synchrotron radiation.

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The categories of this paper are: nucl-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-lat
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio
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The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
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The categories of this paper are: comp-gas
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an
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The categories of this paper are: eess