Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetic order in the pseudogap phase of high-$T_C$ superconductors   One of the leading issues in high-$T_C$ superconductors is the origin of the
pseudogap phase in underdoped cuprates. Using polarized elastic neutron
diffraction, we identify a novel magnetic order in the YBa$_2$Cu$_3$O$_{6+x}$
system. The observed magnetic order preserves translational symmetry as
proposed for orbital moments in the circulating current theory of the pseudogap
state. To date, it is the first direct evidence of an hidden order parameter
characterizing the pseudogap phase in high-$T_C$ cuprates.

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The categories of this paper are: gr-qc
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
2
The categories of this paper are: math
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
7
The categories of this paper are: hep-th
26
The categories of this paper are: bayes-an
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The categories of this paper are: patt-sol
18
The categories of this paper are: econ
1
The categories of this paper are: cs
14
The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg