Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Extremely Weakly Interacting $\Delta S_z = 0$ and $\Delta S_z = 1$
  Excitations and Evidence for Fractional Quantization in a Magnetization
  Plateau: CeSb   The plateau at 1/3 of the saturation magnetization, $M_s$, in the metamagnet
CeSb is accompanied by a state of ferromagnetic layers of spins in an
up-up-down sequence. We measured $M$ and the specific heat, $C$, in the
plateau, spin wave analyses of which reveal two distinct branches of
excitations. Those with $\Delta S_z = 1$ as measured by $M$, coexist with a
much larger population of $\Delta S_z = 0$ excitations measured by $C$ but
invisible to $M$. The large density of $\Delta S_z = 0$ excitations, their
energy gap, and their seeming lack of interaction with $\Delta S_z = 1$
excitations suggest an analogy with astrophysical dark matter. Additionally, in
the middle of the plateau three sharp jumps in $M(H)$ are seen, the size of
which, $0.15 $%$M_s$, is consistent with fractional quantization of
magnetization-per-site in the down-spin layers.

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The categories of this paper are: patt-sol
1
The categories of this paper are: cs
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
0
The categories of this paper are: hep-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: q-alg
10
The categories of this paper are: q-bio
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The categories of this paper are: ao-sci
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The categories of this paper are: mtrl-th
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The categories of this paper are: eess