Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: $Z_4$ Topological Superconductivity in UCoGe   Topological nonsymmorphic crystalline superconductivity (TNCS) is an
intriguing phase of matter, offering a platform to study the interplay between
topology, superconductivity, and nonsymmorphic crystalline symmetries.
Interestingly, some of TNCS are classified into $Z_4$ topological phases, which
have unique surface states referred to as a M\"obius strip or an hourglass, and
have not been achieved in symmorphic superconductors. However, material
realization of $Z_4$ TNCS has never been known, to the best of our knowledge.
Here we propose that the paramagnetic superconducting phase of UCoGe under
pressure is a promising candidate of $Z_4$-nontrivial TNCS enriched by glide
symmetry. We evaluate $Z_4$ invariants of UCoGe by deriving the formulas
relating $Z_4$ invariants to the topology of Fermi surfaces. Applying the
formulas and previous ab-initio calculations, we clarify that three odd-parity
representations, out of four, are $Z_4$-nontrivial TNCS, while the other is
also $Z_2$-nontrivial TNCS. We also discuss possible $Z_4$ TNCS in CrAs and
related materials.

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The categories of this paper are: patt-sol
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The categories of this paper are: comp-gas
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The categories of this paper are: acc-phys
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The categories of this paper are: cmp-lg
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The categories of this paper are: physics
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The categories of this paper are: q-alg
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The categories of this paper are: gr-qc
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The categories of this paper are: plasm-ph
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The categories of this paper are: astro-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-th
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The categories of this paper are: ao-sci
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The categories of this paper are: adap-org
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The categories of this paper are: alg-geom
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The categories of this paper are: funct-an