Cornering the axion-like particle explanation of quasar polarisations
  In a series of paper, it has been shown that the distribution of polarisation
position angles for visible light from quasars is not random in extremely large
regions of the sky. As explained in a recent article, the measurement of
vanishing circular polarisation for such quasars is an important problem for a
mechanism involving the mixing with axion-like particles in external magnetic
fields. In this note, we stress that a recent report of similar coherent
orientations of polarisation in radiowaves further disfavours the need for such
particles, as an effect at these wavelengths would be extremely suppressed or
would directly contradict data.
