Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electrical generation and detection of spin waves in a quantum Hall
  ferromagnet   Spin waves are collective excitations of magnetic systems. An attractive
setting for studying long-lived spin-wave physics is the quantum Hall (QH)
ferromagnet, which forms spontaneously in clean two-dimensional electron
systems at low temperature and in a perpendicular magnetic field. We used
out-of-equilibrium occupation of QH edge channels in graphene to excite and
detect spin waves in magnetically ordered QH states. Our experiments provide
direct evidence for long distance spin wave propagation through different
ferromagnetic phases in the N=0 Landau level, as well as across the insulating
canted antiferromagnetic phase. Our results will enable experimental
investigation of the fundamental magnetic properties of these exotic
two-dimensional electron systems.

27
The categories of this paper are: comp-gas
17
The categories of this paper are: q-fin
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
11
The categories of this paper are: hep-lat
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg