Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Actively controlling the topological transition of dispersion based on
  electrically controllable metamaterials   Topological transition of the iso-frequency contour (IFC) from a closed
ellipsoid to an open hyperboloid, will provide unique capabilities for
controlling the propagation of light. However, the ability to actively tune
these effects remains elusive and the related experimental observations are
highly desirable. Here, tunable electric IFC in periodic structure which is
composed of graphene/dielectric multilayers is investigated by tuning the
chemical potential of graphene layer. Specially, we present the actively
controlled transportation in two kinds of anisotropic zero-index media
containing PEC/PMC impurities. At last, by adding variable capacitance diodes
into two-dimensional transmission-line system, we present the experimental
demonstration of the actively controlled magnetic topological transition of
dispersion based on electrically controllable metamaterials. With the increase
of voltage, we measure the different emission patterns from a point source
inside the structure and observe the phase-transition process of IFCs. The
realization of actively tuned topological transition will opens up a new avenue
in the dynamical control of metamaterials.

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The categories of this paper are: astro-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: eess
21
The categories of this paper are: adap-org
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The categories of this paper are: hep-ex
4
The categories of this paper are: cond-mat
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The categories of this paper are: solv-int
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The categories of this paper are: nlin
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
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The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: funct-an
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The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph