Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Circular dichroism of second harmonic generation response   Polarization-dependent photon spectroscopy (dichroism) of the second-harmonic
generation (SHG) response is shown to reveal chiral and magnetic properties of
a sample. Two dichroic signals are allowed with electric-dipole (E1) and
electric-quadrupole (E2) scattering events, and both require circular
polarization in the primary beam. Explicit expressions for electronic
multipoles, which benefit from equivalent electronic operators, in NCD and MCD
of the SHG response are derived using theoretical techniques from atomic
physics.

1
The categories of this paper are: cs
0
The categories of this paper are: hep-ph
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
10
The categories of this paper are: q-bio
21
The categories of this paper are: adap-org
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin