Mixing of photons with light pseudoscalars in time-dependent magnetic   fields
  The effects of an external time-dependent magnetic field in the conversion probability of photon-to-axion-like particles are studied. Our findings show that for a certain time regime, the amplitude of the produced axion-like field can be enlarged with respect to the static case, thus, enhancing the probability of conversion. 
Paola Arias, Ariel Arza and, Jorge Gamboa
hep-ph