Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Triply-Periodic Smectics   Twist-grain-boundary phases in smectics are the geometrical analogs of the
Abrikosov flux lattice in superconductors. At large twist angles, the nonlinear
elasticity is important in evaluating their energetics. We analytically
construct the height function of a pi/2 twist-grain-boundary phase in smectic-A
liquid crystals, known as Schnerk's first surface. This construction, utilizing
elliptic functions, allows us to compute the energy of the structure
analytically. By identifying a set of heretofore unknown defects along the
pitch axis of the structure, we study the necessary topological structure of
grain boundaries at other angles, concluding that there exist a set of
privileged angles and that the \pi/2 and \pi/3 grain boundary structures are
particularly simple.

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The categories of this paper are: q-fin
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The categories of this paper are: chao-dyn
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The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
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The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
32
The categories of this paper are: atom-ph
13
The categories of this paper are: quant-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-lat
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The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
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The categories of this paper are: acc-phys
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The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph