Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Janus Waves   We show the existence of a family of waves that share a common interesting
property affecting the way they propagate and focus. These waves are a
superposition of twin waves, which are conjugate to each other under inversion
of the propagation direction. In analogy to holography, these twin "real" and
"virtual" waves are related respectively to the converging and the diverging
part of the beam and can be clearly visualized in real space at two distinct
foci under the action of a focusing lens. Analytic formulas for the intensity
distribution after focusing are derived, while numerical and experimental
demonstrations are given for some of the most interesting members of this
family, the accelerating Airy and ring-Airy beams

30
The categories of this paper are: q-alg
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
4
The categories of this paper are: cond-mat
36
The categories of this paper are: cmp-lg
12
The categories of this paper are: nucl-th
35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
21
The categories of this paper are: adap-org
9
The categories of this paper are: nlin