R. Battesti

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.

Bloch Oscillations of Ultracold Atoms: A Tool for a Metrological Determination of h/m~R~b

We use Bloch oscillations in a horizontal moving standing wave to transfer a large number of photon recoils to atoms with a high efficiency (99.5% per cycle). By measuring the photon recoil of 87Rb, using velocity-selective Raman transitions to select a subrecoil velocity class and to measure the final accelerated velocity class, we have determined h/m(Rb) with a relative precision of 0.4 ppm. To exploit the high momentum transfer efficiency of our method, we are developing a vertical standing wave setup. This will allow us to measure h/m(Rb) better than 10(-8) and hence the fine structure constant alpha with an uncertainty close to the most accurate value coming from the (g-2) determination.

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.

Magnetic linear birefringence measurements using pulsed fields

In this paper we present the realization of further steps toward the measurement of the magnetic birefringence of a vacuum using pulsed fields. After describing our experiment, we report the calibration of our apparatus using nitrogen gas and discuss the precision of our measurement giving a detailed error budget. Our best present vacuum upper limit is

Vacuum magnetic linear birefringence using pulsed fields: the BMV experiment

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Birefringence of interferential mirrors at normal incidence: Experimental and computational study

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Limits on nonlinear electrodynamics

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A Transportable Pulsed Magnet System for Fundamental Investigations in Quantum Electrodynamics and Particle Physics

per 4 ms acquisition time. We finally discuss the improvements necessary to reach our final goal.

Faraday and Cotton-Mouton Effects of Helium at

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.