Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Imaging the controllable rotation of a skyrmion crystal driven by
  femtosecond laser pulses   Control of topological magnetic textures has attracted intense interest due
to the potential applications for these structures in spintronic devices.
Recent advances in electron microscopy have enabled imaging of individual
skyrmions, however the full understanding of their ultrafast dynamics has
remained inaccessible. Here we show via cryo- Lorentz microscopy that a single
circularly polarized femtosecond laser pulse can induce controlled rotation of
a skyrmion crystal. Pulses of light with an energy below the bandgap of the
Mott insulator Cu2OSeO3 drive spin currents whose direction and strength
determine the direction and degree of the skyrmion crystal rotation.
Thermodynamic calculations confirm that the rotation dynamics triggered take
place on a timescale more than six orders of magnitude faster than previously
measured. This direct manipulation of topological order via laser pulses can be
used to engineer spin-based logical devices on much faster timescales than
available methods.

16
The categories of this paper are: stat
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin
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The categories of this paper are: math-ph
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
2
The categories of this paper are: math
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
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The categories of this paper are: eess
29
The categories of this paper are: funct-an
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The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph