Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electromagnetic Imaging with Atomic Magnetometers: A Novel Approach to
  Security and Surveillance   We describe our research programme on the use of atomic magnetometers to
detect conductive objects via electromagnetic induction. The extreme
sensitivity of atomic magnetometers at low frequencies, up to seven orders of
magnitude higher than a coil-based system, permits deep penetration through
different media and barriers, and in various operative environments. This
eliminates the limitations usually associated with electromagnetic detection.

36
The categories of this paper are: cmp-lg
20
The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
6
The categories of this paper are: astro-ph
0
The categories of this paper are: hep-ph
22
The categories of this paper are: chao-dyn
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
29
The categories of this paper are: funct-an
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th