Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Inelastic Neutron and X-ray Scattering from Incommensurate Magnetic
  Systems   Neutrons and X-rays are powerful probes for studying magnetic and lattice
excitations in strongly correlated materials over very wide ranges of momentum
and energy transfers. In the focus of the present work are the incommensurate
magnetic systems MnSi and Cr. Under application of a magnetic field, helically
ordered MnSi transforms into a weak itinerant ferromagnet. Using polarized
neutrons we demonstrate that the Stoner excitations are spin flip excitations.
The amplitude (longitudinal) fluctuations associated with the magnon modes are
already strong far away from T_C. Interestingly, even the non spin flip
excitations associated with the Stoner modes are observable. In Cr, we have
observed Kohn anomalies in the phonon spectrum at those incommensurate
positions in reciprocal space, where the spin density wave is observed. The
corresponding phonon and magnon modes are not coupled. In addition, an
anomalous softening of a transverse phonon branch along the N-H zone boundary
line is observed that is caused by strong electron phonon coupling. High
resolution neutron scattering indicate that the low energy Fincher-Burke
excitations may rather correspond to localized modes in momentum and energy and
not to propagating collective modes. Finally, we demonstrate that in the near
future it may become feasible to investigate excitations in very small samples
thus allowing to measure the dynamics of strongly correlated materials under
extreme conditions and in the vicinity of quantum phase transitions.

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The categories of this paper are: physics
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The categories of this paper are: bayes-an
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The categories of this paper are: eess
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The categories of this paper are: hep-ph
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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: econ
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The categories of this paper are: atom-ph
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The categories of this paper are: adap-org
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-th
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The categories of this paper are: comp-gas
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The categories of this paper are: alg-geom
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The categories of this paper are: supr-con
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The categories of this paper are: q-bio
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The categories of this paper are: cmp-lg