Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Watching outside while under a carpet cloak of invisibility   We demonstrate in this letter a unique approach for watching outside while
hiding in a carpet cloaking based on transformation optics. Unlike conventional
carpet cloaking, which screens all the incident electromagnetic waves, we break
the cloak and allow incident light get into the carpet. Hence outside
information is detected inside the cloak. To recover the invisible cloaking,
complementary techniques are applied in the broken space. Consequently, a
hiding-inside-and-watching-outside (HIWO) carpet cloak is sewed, which works as
a perfectly invisible cloaking and allows surveillance of the outside at the
same time. Our work provides a strategy for ideal cloak with "hiding" and
"watching" functions simultaneously.

13
The categories of this paper are: quant-ph
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
22
The categories of this paper are: chao-dyn
18
The categories of this paper are: econ
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess