F. Della Valle

New PVLAS results and limits on magnetically induced optical rotation and ellipticity in vacuum

In 2006 the PVLAS collaboration reported the observation of an optical rotation generated in vacuum by a magnetic field. To further check against possible instrumental artifacts, several upgrades to the PVLAS apparatus have been made during the past year. Two data taking runs, at the wavelength of 1064 nm, have been performed in the new configuration with magnetic field strengths of 2.3 and 5 T. The 2.3 T field value was chosen in order to avoid stray fields. The new observations do not show the presence of a rotation signal down to the levels of

Limits on low energy photon-photon scattering from an experiment on magnetic vacuum birefringence

1.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}\text{ }\text{ }\mathrm{rad}

Experimental method to detect the magnetic birefringence of vacuum

at 5 T and

Measurements of vacuum magnetic birefringence using permanent dipole magnets: the PVLAS experiment

1.0\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}\text{ }\text{ }\mathrm{rad}

Frequency locking of a Nd:YAG laser using the laser itself as the optical phase modulator

at 2.3 T (at 95% C.L.) with 45 000 passes in the magnetic field zone. In the same conditions no ellipticity signal was detected down to

Co dissociation and recombination reactions on Ni(100)

1.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}

The measurement of vacuum polarization: The PVLAS experiment

at 2.3 T (at 95% C.L.), whereas at 5 T a signal is still present. The physical nature of this ellipticity as due to an effect depending on

PVLAS: Vacuum Birefringence And Production And Detection Of Nearly Massless, Weakly Coupled Particles By Optical Techniques

{B}^{2}

Very high Q frequency‐locked Fabry–Perot cavity

can be excluded by the measurement at 2.3 T. These new results completely exclude the previously published magnetically induced vacuum dichroism results, indicating that they were instrumental artifacts. These new results therefore also exclude the particle interpretation of the previous PVLAS results as due to a spin-zero boson. The background ellipticity at 2.3 T can be used to determine a new limit on the total photon-photon scattering cross section of

MIR: An experiment for the measurement of the dynamical Casimir effect

{\ensuremath{\sigma}}_{\ensuremath{\gamma}\ensuremath{\gamma}}l4.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}34}\text{ }\text{ }\mathrm{barn}