Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: U(1)-Symmetry protected Dirac nodal loops of triplons in SrCu2(BO3)2   We demonstrate the appearance of symmetry protected triplon Dirac modal lines
in the low energy excitation spectrum of a realistic microscopic model of the
geometrically frustrated quantum magnet SrCu2(BO3)2 in its high symmetry phase.
The symmetry-allowed Dzyaloshinskii-Moriya interactions induce dispersive
trilpon bands within the bond-operator formalism that cross linearly over an
extended closed path in the Brillouin zone. Our results establish that the
nodal lines are protected by a $U(1)$-symmetry and robust against perturbations
that preserve this symmetry. In the presence of a longitudinal field, the nodal
loop shrinks and vanishes for a sufficiently strong field.

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The categories of this paper are: adap-org
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The categories of this paper are: q-alg
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The categories of this paper are: acc-phys
6
The categories of this paper are: astro-ph
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
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The categories of this paper are: patt-sol
36
The categories of this paper are: cmp-lg
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The categories of this paper are: quant-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: math-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-th
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The categories of this paper are: eess
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The categories of this paper are: gr-qc