Pulsars are highly magnetized and rapidly rotating neutron stars. The magnetic field can reach the critical magnetic field from which quantum effects of the vacuum becomes relevant, giving rise to magnetooptic properties of vacuum characterized as an
effective non linear medium. One spectacular consequence of this prediction is a macroscopic friction that leads to an additional contribution in the spindown of pulsars. In this paper, we highlight some observational consequences and in particular derive new constraints on the parameters of the Crab pulsar and J0540-6919.
In this letter we show that Quantum Vacuum Friction (QVF) should play an important role in neutron star evolution. Taking into account this effect we show that magnetars could be understood as a natural evolution of standard pulsars. For the Crab pul
sar, of which the characteristic age is known, we present the first completely coherent time evolution for its period and braking index. For this pulsar we also give the predicted value of the current first derivative of the braking index, providing a very important test to confirm QVF.
In this paper we present a review of the existing data on interferential mirror birefringence. We also report new measurements of two sets of mirrors that confirm that mirror phase retardation per reflection decreases when mirror reflectivity increas
es. We finally developed a computational code to calculate the expected phase retardation per reflection as a function of the total number of layers constituting the mirror. Different cases have been studied and we have compared computational results with the trend of the experimental data. Our study indicates that the origin of the mirror intrinsic birefringence can be ascribed to the reflecting layers close to the substrate.
