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Philippe Tourrenc

Publications and source records attributed to Philippe Tourrenc.

3 recordsLinked to original sources

The "Forgotten" Process : the emission stimulated by matter waves

In a famous paper where he introduces the A and B coefficients, Einstein considered that atomic decays of excited atoms can be stimulated by light waves. Here we consider that atomic decays can also be stimulated by atomic waves. It is however necessary to change the Maxwell-Boltzmann statistics of thermal equilibrium into Bose-Einstein statistics and to introduce a coefficient C which complements the list of the coefficients introduced by Einstein. Stimulated emission of light can be considered as the first step towards the laser. Similarly, stimulated production of matter waves can be considered as the basic phenomenon for an atom-laser. Most of the results that we obtain here are not new. However, the method that we use remains very close to elementary classical physics and emphasizes the symmetry between electromagnetic and matter waves from various points of view.

quant-ph

Tidal gravitational effects in a satellite

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.

gr-qc