Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Higher Harmonics in Non-Linear Vacuum from QED Effects Without Low Mass
  Intermediate Particles   We show that in the presence of a slowly rotating strong transverse magnetic
field there is an infinite spectrum of harmonic wave functions $A_n$ due to the
first order QED correction (in $\alpha^2$) given by the Euler-Heisenberg
Lagrangian. The frequency shifts are integer multiples $\pm \omega_0 n$ of the
magnetic field angular frequency rotation $\omega_0=2\pi\nu_m$ and the several
modes $n$ are coupled to the nearest harmonics $n\pm 1$. This is a new effect
due to QED vacuum fluctuations, not exploit before, that can explain, both
qualitatively and quantatively, the recent experimental results of the PVLAS
collaboration without the need of a low mass intermediate particle, hence
dismiss the recent claim of the discovery of the axion. [Erratum: The PVLAS
signal cannot be explained by this mechanism.]

9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
21
The categories of this paper are: adap-org
6
The categories of this paper are: astro-ph
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
14
The categories of this paper are: math-ph
25
The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
35
The categories of this paper are: mtrl-th