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Atomic wave interferometers are tied to a telescope pointing towards a faraway star in a nearly free falling satellite. Such a device is sensitive to the acceleration and the rotation relatively to the local inertial frame and to the tidal gravitational effects too. We calculate the rotation of the telescope due to the aberration and the deflection of the light in the gravitational field of a central mass (the Earth and Jupiter). Within the framework of a general parametrized description of the problem, we discuss the contributions which must be taken into account in order to observe the Lense-Thirring effect. Using a geometrical model, we consider some perturbations to the idealized device and we calculate the corresponding effect on the periodic components of the signal. Some improvements in the knowledge of the gravitational field are still necessary as well as an increase of the experimental capabilities; however our conclusions support a reasonable optimism for the future. Finally we put forward the necessity of a more complete, realistic and powerful model in order to obtain a definitive conclusion on the feasibility of the experiment as far as the observation of the Lense-Thirring effect is involved.

This article deals with the gravitational lensing (GL) of gravitational waves (GW). We compute the increase in the number of detected GW events due to GL. First, we check that geometrical optics is valid for the GW frequency range on which Earth-based detectors are sensitive, and that this is also partially true for what concerns the future space-based interferometer LISA. To infer this result, both the diffraction parameter and a cut-off frequency are computed. Then, the variation in the number of GW signals is estimated in the general case, and applied to some lens models: point mass lens and singular isothermal sphere (SIS profile). An estimation of the magnification factor has also been done for the softened isothermal sphere and for the King profile. The results appear to be strongly model-dependent, but in all cases the increase in the number of detected GW signals is negligible. The use of time delays among images is also investigated.

We consider a nearly free falling Earth satellite where atomic wave interferometers are tied to a telescope pointing towards a faraway star. They measure the acceleration and the rotation relatively to the local inertial frame. We calculate the rotation of the telescope due to the aberrations and the deflection of the light in the gravitational field of the Earth. We show that the deflection due to the quadrupolar momentum of the gravity is not negligible if one wants to observe the Lense-Thirring effect of the Earth. We consider some perturbation to the ideal device and we discuss the orders of magnitude of the phase shifts due to the residual tidal gravitational field in the satellite and we exhibit the terms which must be taken into account to calculate and interpret the full signal. Within the framework of a geometric model, we calculate the various periodic components of the signal which must be analyzed to detect the Lense-Thirring effect. We discuss the results which support a reasonable optimism. As a conclusion we put forward the necessity of a more complete, realistic and powerful model in order to obtain a final conclusion on the theoretical feasibility of the experiment as far as the observation of the Lense-Thirring effect is involved.

The Dulkyn interferometer in Kazan is an active ring laser where the light propagates along two different paths. It has been developed with the idea that it could detect low frequency gravitational waves on Earth. Considering Dulkyn as a detector of periodic strains of order of h~ 10−22at low frequencies (10−3Hz−10−5Hz) we calculate that 30 W is the order of magnitude of the optical power necessary to beat the photon noise in the case of a long observation time (T= 4 months) and a reasonable signal to noise ratio (r= 3). We estimate that the displacement noise of the mirrors must not exceed 5×10−19m/$\sqrt{{Hz}}$. Dulkyn is also sensitive to accelerations and rotations. The acceleration noise does not seem to be troublesome ($\widetilde{g}\lesssim 0.1{m} {s}^{-2}/\sqrt{{Hz}}$), but the angular velocity noise must be less than 5×10−11s−1/$\sqrt{{Hz}}$. The maximum strain (10−22) is obtained with free (pendulous) mirrors. Out of resonance, the strain is many orders of magnitude smaller when the mirrors are fixed on a rigid support. Such a case would rule out the possibility of a detection. As a conclusion we emphasize that the Dulkyn design does not bring any decisive improvement for the detection of low frequency gravitational waves on Earth.

A generalization of the well-known Dirac equation authorizes us to study the behaviour of an electron in gravitational and electromagnetic fields, therefrom we can develop a pattern that describes an atom in Schwarzschild's and Robertson-Walker's fields. The induced phenomena and their orders of magnitude are set out. Conclusions are drawn concerning the ability of observing black holes and gravitational collapses. Una generalizzazione della ben nota equazione di Dirac ci autorizza a studiare il comportamento di un elettrone in campi gravitazionali ed elettromagnetici, da cui possiamo sviluppare uno schema che descrive un atomo nei campi di Schwarzschild e di Robertson-Walker. Si espongono i fenomeni indotti ed i loro ordini di grandezza. Si traggono conclusioni riguardanti la possibilità di osservare buchi neri e collassi gravitazionali. На основе обобщения хорошо известного уравнения Дирака мы исследуем поведение электрона в гравитационном и электромагнитном полях. Предложенный подход позволяет нам построить модель, которая описывает атом в полях Шварцшильда и Робертсона-Уокера. Обсуждаются индуцированные явления и приводятся порядки величин, характеризующих эти явления. Делаются заключения относительно возможности наблюдения черных дыр и гравитационных коллапсов.

Some phenomena of resonance between a gravitationnal wave and an electromagnetic radiation contained in a cavity are studied; the use of a simplified pattern allows to follow calculations to their end and to pick out orders of magnitude. The whole of this study is done by means of a perturbative method restricted to first order, within Einstein-Maxwell’s theory. Nous étudions certains phénoménés de résonance entre une onde de gravitation et un rayonnement électromagnétique contenu dans une cavité. L’emploi d’un modéle simplifié permet de mener les calculs jusqu’á leur terme et de dégager des ordes de grandeur. L’ensemble de cette étude est effectuée au moyen d’une méthode perturbative limitée au promier ordre, dans le cadre de la théorie d’Einstein-Maxwell. Si studiano certi fenomeni di risonanza fra un’onda gravitazionale e una radiazione elettromagnetica contenuta in una cavità. Si riesce, per mezzo di un modello semplificato, a condurre a termine i calcoli ed a cogliere degli ordini di grandezza. Si è effettuato l’insieme dello studio per mezzo di un metodo perturbativo limitato al primo ordine, nel quadro della teoria di Einstein-Maxwell.

Abstract: We analyze the Michelson type experiment performed by Brillet and Hall. The order of magnitude of the gravitational effect (a beating frequency between two lasers) is calculated. We prove that Newtonian tidal forces could be observed when they originate from the oblateness of the Earth, from its rotation, from local masses, from the Moon or the Sun but not from the Galaxy (contrary to what has been recently claimed). We conclude that it is important to build a new parametrized theoretical framework for the analysis of high-precision experiments.

We generalize Robertson's frame designed to discuss the experimental tests of Special Relativity. We include parametrized post-Newtonian theories of gravitation in the new frame. This generalization includes covariant equations for the motion of a test particle. We discuss the possibility of new tests such as tests of Special Relativity in astronomy.

Gravitational radiation is considered within the first-order approximation. A pattern of an electromagnetic cavity is studied: Gravitational waves give rise to a deformation of the planes limiting the cavity. This deformation alters the electromagnetic radiation. Several cases are studied and orders of magnitude are put forward.

Gravitational radiation is considered within the first-order approximation. A classical gravitational background yields transitions between quantum electromagnetic states in a cavity. Orders of magnitude are picked out from special patterns. The interest of second-order effects is emphasized and experimental possibilities are sketched.

We have analyzed pulse width and timing jitter in passively mode-locked two-section InAs quantum-dot lasers emitting at 1310 nm and have identified two distinct, extensive mode-locked regions with robust short pulses and low timing jitter. A record combination of 2 ps pulses and 25 fs/cycle timing jitter (500 fs, 1-100 MHz), with 1 mW average output power per facet, is demonstrated.