Magnetic and electric properties of quantum vacuum

In this report we show that vacuum is a nonlinear optical medium and we discuss what are the optical phenomena 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 has been observed experimentally yet. Progresses in field sources and related techniques seem to indicate that in few years vacuum nonlinear optics will be accessible to human investigation.Comment: Reports on Progress in Physics (2013) in pres

On the speed of light in a vacuum in the presence of a magnetic field

The nature of light, the existence of magnetism, the physical meaning of a vacuum are problems so deeply related to philosophy that they have been discussed for thousands of years. In this paper, we concentrate ourselves on a question that concerns the three of them: does light speed in a vacuum change when a magnetic field is present? The experimental answer to this fundamental question has not yet been given even if it has been stated in modern terms for more than a century. To fully understand the importance of such a question in physics, we review the main facts and concepts from the historical point of view.Comment: 31 pages, 17 figures; corrected reference formattin

Bloch oscillations of ultracold atoms: a tool for a metrological determination of h/mRbh/m_{Rb}

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 $^{87}Rb$, 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 set-up. 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

Circular and linear magnetic birefringences in xenon at λ=1064\lambda = 1064 nm

The circular and linear magnetic birefringences corresponding to the Faraday and the Cotton-Mouton effects, respectively, have been measured in xenon at $\lambda = 1064$ nm. The experimental setup is based on time dependent magnetic fields and a high finesse Fabry-Perot cavity. Our value of the Faraday effect is the first measurement at this wavelength. It is compared to theoretical predictions. Our uncertainty of a few percent yields an agreement at better than 1$\sigma$ with the computational estimate when relativistic effects are taken into account. Concerning the Cotton-Mouton effect, our measurement, the second ever published at $\lambda = 1064$ nm, agrees at better than $1\sigma$ with theoretical predictions. We also compare our error budget with those established for other experimental published values

Quantum vacuum magneto-optics

International audienc

Search for photon oscillations into massive particles

International audienceIn this paper, we present the final results of our experiment on photon-axion oscillations in the presence of a magnetic field, which took place at LULI (Laboratoire pour l'Utilisation des Lasers Intenses, Palaiseau, France). Our null measurement allowed us to exclude the existence of axions with inverse coupling constant $M>9.\times 10^5$ GeV for low axion masses and to improve the preceding BFRT limits by a factor 3 or more for axion masses $1.1\, \mbox{meV

Accélération d'atomes ultrafroids ; mesure de h/M

This work describes anexperiment whose purpose is the measurement of the atomic recoilvelocity Vr. The ratio h/M, where h is the Planckconstant and M the atomic mass, and then the fine structureconstant can be deduced from this measurement. The experiment ismade up of three steps. Firstly we select, in a cloud of coldatoms, a subrecoil velocity class with a Raman transition. Then weaccelerate the atoms with a standing wave in the atomic frame (inthe solid state physics approach, this is known as Blochoscillations). Finally, we measure the final atomic velocity witha new Raman transition. The determination of the initial and finalatomic velocities leads to the determination of the momentumtransfer and so, of the atomic recoil velocity. We present in thisscript the first results of this experimental work.Cette thèse décrit une expérience de mesure dela vitesse de recul Vr d'un atome. Cette mesure permet dedéduire le rapport h/M, où h désigne la constante de Plancket M la masse de l'atome considéré, afin d'obtenir la valeurde la constante de structure fine. Le principe del'expérience est le suivant. A partir d'un nuage d'atomes froids,nous sélectionnons une classe de vitesse subrecul à l'aide d'unetransition Raman. Ensuite, nous accélérons les atomes de manièrecohérente à l'aide d'une onde stationnaire dans le référentiel del'atome (cet effet est analogue aux oscillations de Bloch enphysique du solide). Enfin, nous mesurons la vitesse finale desatomes par une nouvelle transition Raman. La connaissance desvitesses finale et initiale nous permet de remonter à la quantitéde mouvement transférée et donc à la vitesse de recul de l'atome.Nous présentons dans ce manuscrit les premiers résultats de cetravail expérimental

Accélération d'atomes ultrafroids (mesure de h/M)

PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF