Testing Quantum Electrodynamics: vacuum polarizability and Casimir forces

Besides ruling the dynamics of electric charged particles and photons in the microscopic domain, quantization of the electromagnetic field gives also rise to macroscopic observable effects. We report on the status of two experiments we are carrying out at the INFN Legnaro Laboratories on macroscopic phenomena of the vacuum of quantum electrodynamics, the birefringence induced by a magnetic field and the Casimir forces.