Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Zero-refraction in natural materials and the mechanism of metal
  superlens   We found that a single negative material has a character of zero-refraction
in near field, and point out that the mechanism of a metal superlens to image
with the resolution exceeding the diffraction limitation is different from that
of a perfect lens made of a double negative material. The principle of metal
superlens is disclosed. Our numerical results based on the zero-refraction
character coincide with the experimental results well. This work brings new
understanding about the single negative materials and will lead the
applications of metal superlens in right way.

9
The categories of this paper are: nlin
7
The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
23
The categories of this paper are: solv-int
16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
17
The categories of this paper are: q-fin
5
The categories of this paper are: gr-qc
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas