Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Neutron scattering off Weyl semimetals   We present how to detect type-$1$ Weyl nodes in a material by inelastic
neutron scattering. Such an experiment first of all allows one to determine the
dispersion of the Weyl fermions. We extend the reasoning to produce a
quantitative test of the Weyl equation taking into account realistic
anisotropic properties. These anisotropies are mostly contained in the form of
the emergent magnetic moment of the excitations, which determines how they
couple to the neutron. Although there are many material parameters, we find
several quantitative predictions that are universal and demonstrate that the
excitations are described by solutions to the Weyl equation. The realistic,
anisotropic coupling between electrons and neutrons implies that even fully
unpolarized neutrons can reveal the spin-momentum locking of the Weyl fermions
because the neutrons will couple to some components of the Weyl fermion
pseudospin more strongly. On the other hand, in an experiment with polarized
neutrons, the scattered neutron beam remains fully polarized in a direction
that varies as a function of momentum transfer (within the range of validity of
the Weyl equation). This allows measurement of the chirality of Weyl fermions
for inversion symmetric nodes. Furthermore, we estimate that the scattering
rate may be large enough for such experiments to be practical; in particular,
the magnetic moment may be larger than the ordinary Bohr magneton, compensating
for a small density of states.

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The categories of this paper are: eess
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The categories of this paper are: hep-ex
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The categories of this paper are: gr-qc
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The categories of this paper are: solv-int
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The categories of this paper are: cmp-lg
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The categories of this paper are: chem-ph
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The categories of this paper are: q-fin
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The categories of this paper are: funct-an
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The categories of this paper are: hep-lat
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The categories of this paper are: acc-phys
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The categories of this paper are: ao-sci
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The categories of this paper are: stat
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The categories of this paper are: alg-geom
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The categories of this paper are: plasm-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: adap-org