Mendonca, J. Tito, Dias de Deus, J. and Castelo Ferreira, P. (2006 (7)), "Higher harmonics in non-linear vacuum from QED effects without low mass intermediate particles", Phys. Rev. Lett., 97: 100403;(Erratum: 269901).
Abstract: 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 $+/- \\omega_0 n$ of the magnetic field angular frequency rotation $\\omega_0=2\\pi\\nu_m$ and the several modes $n$ are coupled to the nearest harmonics $n +/- 1$. 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.]
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