Carlo Rizzo

The Cotton-Mouton effect in gases: Experiment and theory

When polarized light passes through a material in the presence of a strong magnetic field, birefringence is observed. This is known as the Cotton-Mouton effect. Owing to the increasing sophistication of both experimental and computational techniques, this particular aspect of magneto-optics has been investigated increasingly in the last few years. In this review the basic facts concerning both experiment and theory are discussed and tables summarizing all currently known gas-phase data are presented.

The BMV experiment : a novel apparatus to study the propagation of light in a transverse magnetic field

Abstract.In this paper, we describe in detail the BMV (Biréfringence Magnétique du Vide) experiment, a novel apparatus to study the propagation of light in a transverse magnetic field. It is based on a very high finesse Fabry-Perot cavity and on pulsed magnets specially designed for this purpose. We justify our technical choices and we present the current status and perspectives.

Magnetic and electric properties of a quantum vacuum

In this report we show that a vacuum is a nonlinear optical medium and discuss what the optical phenomena are that should exist in the framework of the standard model of particle physics. We pay special attention to the low energy limit. The predicted effects for photons of energy smaller than the electron rest mass are of such a level that none have yet been observed experimentally. Progress in field sources and related techniques seem to indicate that in a few years vacuum nonlinear optics will be accessible to human investigation.

Proton Zemach radius from measurements of the hyperfine splitting of hydrogen and muonic hydrogen

While measurements of the hyperfine structure of hydrogen-like atoms are traditionally regarded as test of bound-state QED, we assume that theoretical QED predictions are accurate and discuss the information about the electromagnetic structure of protons that could be extracted from the experimental values of the ground state hyperfine splitting in hydrogen and muonic hydrogen.Using recent theoretical results on the proton polarizability effects and the experimentalhydrogen hyperfine splitting we obtain for the Zemach radius of the proton the value 1.040(16) fm. We compare it to the various theoretical estimatesthe uncertainty of which is shown to be larger that 0.016 fm.This point of view gives quite convincing arguments in support of projects to measure the hyperfine splitting of muonic hydrogen.

Experimental method to detect the magnetic birefringence of vacuum

We describe the principle and the status of the PVLAS experiment which is being assembled at INFN Laboratori Nazionali di Legnaro (Legnaro, Padua, Italy) to look for coherent effects, related to the QED vacuum structure, on the propagation of a polarized light beam in a strong magnetic field.

The Cotton–Mouton effect of furan and its homologues in the gas phase, for the pure liquids and in solution

The tensor components of the electric dipole polarizability at a wavelength of 632.8 nm, those of the magnetizability and the anisotropy of the static hypermagnetizability of furan, thiophene, and selenophene are computed using density functional theory (DFT). The polarizable continuum model (PCM) is employed to describe the system in the condensed phase. We can thus compare the temperature dependence of the Cotton–Mouton constant for the three molecules, both in the gas and in the condensed phase, pure liquids, and solutions, with the results of experiment performed using a 17 T radial access Bitter magnet at the Grenoble High Magnetic Field Laboratory. This allows to analyze, in a direct interaction of theory and experiment, the performance of DFT and PCM in describing high order nonlinear mixed electric and magnetic effects in condensed phase.

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

We report frequency locking of a Nd:YAG tunable laser to a 2000 finesse 87‐cm‐long Fabry–Perot cavity in air using the Pound–Drever technique. The novelty is that the necessary phase modulation of the beam is obtained using the laser directly instead of an external phase modulator (Pockels cell). The spurious relative amplitude modulation using this method was ∼3×10−5 with a modulation index β∼1 and the spectral density of the frequency difference between the laser and the cavity is below 1 mHz/√Hz in the region 1–500 Hz.

Photon regeneration experiment for axion search using x-rays.

In this Letter we describe our novel photon regeneration experiment for the axionlike particle search using an x-ray beam with a photon energy of 50.2 and 90.7 keV, two superconducting magnets of 3 T, and a Ge detector with a high quantum efficiency. A counting rate of regenerated photons compatible with zero has been measured. The corresponding limits on the pseudoscalar axionlike particle-two-photon coupling constant is obtained as a function of the particle mass. Our setup widens the energy window of purely terrestrial experiments devoted to the axionlike particle search by coupling to two photons. It also opens a new domain of experimental investigation of photon propagation in magnetic fields.

Vacuum magnetic linear birefringence using pulsed fields: status of the BMV experiment

We present the current status of the BMV experiment. Our apparatus is based on an up-to-date resonant optical cavity coupled to a transverse magnetic field. We detail our data acquisition and analysis procedure which takes into account the symmetry properties of the raw data with respect to the orientation of the magnetic field and the sign of the cavity birefringence. The measurement result of the vacuum magnetic linear birefringence kCM presented in this paper was obtained with about 200 magnetic pulses and a maximum field of 6.5 T, giving a noise floor of about 8 × 10-21 T-2 at 3σ confidence level.

Looking for Light Pseudoscalar Bosons in the Binary Pulsar System J0737-3039

We present numerical calculations of the photon-light-pseudoscalar-boson (LPB) production in the recently discovered binary pulsar system J0737-3039. Light pseudoscalar bosons oscillate into photons in the presence of strong magnetic fields. In the context of this binary pulsar system, this phenomenon attenuates the light beam emitted by one of the pulsars, when the light ray goes through the magnetosphere of the companion pulsar. We show that such an effect is observable in the gamma-ray band since the binary pulsar is seen almost edge-on, depending on the values of the LPB mass and on the strength of its two-photon coupling. Our results are surprising in that they show a very sharp and significant (up to 50%) transition probability in the gamma-ray (> tens of MeV) domain. The observations can be performed by the upcoming NASA GLAST mission.