Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Indirect observation of phase conjugate magnons from non-degenerate
  four-wave mixing   A phase conjugate mirror utilising four-wave mixing in a magnetic system is
experimentally realised for the first time. Indirect evidence of
continuous-wave phase conjugation has been observed experimentally and is
supported by simulations. The experiment utilizes a pump-probe method to excite
a four-wave mixing process. Two antennae are used to pump a region of a
thin-film yttrium iron garnet waveguide with magnons of frequency $f_{1}$ to
create a spatio-temporally periodic potential. As the probe magnons of
$f_{\mathrm{p}}$ impinge on the pumped region, a signal with frequency
$f_{\mathrm{c}} = 2f_{1}-f_{\mathrm{p}}$ is observed. The amplitude of the
nonlinear signal was highly dependent on the applied magnetic field $H$. Width
modes of the probe magnons and standing wave modes of the pump magnons were
shown to affect the amplitude of the signal at $f_{\mathrm{c}}$. Experimental
data is compared with simulations and theory to suggest that $f_{\mathrm{c}}$
is a phase conjugate of $f_{\mathrm{p}}$.

11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics
5
The categories of this paper are: gr-qc
21
The categories of this paper are: adap-org
19
The categories of this paper are: eess
18
The categories of this paper are: econ
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
17
The categories of this paper are: q-fin
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th