Interference matter-wave

Inertial sensors are useful devices in both science and industry. Higher precision sensors could find practical scientific applications in the areas of general relativity (Chow et ah, 1985), geodesy and geology. Important applications of such devices occur also in the field of navigation, surveying and analysis of earth structures. Matter-wave interferometry has recently shown its potential to be an extremely sensitive probe for inertial forces (Clauser, 1988). First, neutron interferometers have been used to measure the Earth rotation (Colella et ah, 1975) and the acceleration due to gravity (Werner et ah, 1979) in the end of the seventies. In 1991, atom interference techniques have been used in... 

A second interpretation of the Aharonov-Bohm effect was devised by Boyer [65,66], who used matter waves associated to moving electrons. Waves coming from each slit interfere with a phase shift = 2jidistance between two slits. If P is the impulse of an electron in the beam, the de Broglie relation gives us P 2nh/X. This results in the fact that the phase... 

Formally, we describe the state of the particle during the propagation as a coherent superposition of states, in particular of position states, that are classically mutually exclusive. A classical object will either take one or the other path for sure. A quantum object cannot be said to do that since the intrinsic information content of the quantum system is insufficient to allow such a description [Brukner 2002], Matter wave interferometers prove this experimentally. The intriguing part is that a full interference visibility can only be obtained if we exclude all possibilities of detecting, even in principle, the... 

In the last section results of a matter wave interference method are presented which has been developed to probe very weak excitations at ultra-low momentum. The interference between the excitations and the condensate leads to strong density modulations after the release of the cloud, whose contrast is a heterodyne probe of the excitation strength. 

Detection of excitations using matter-wave interference... 

The high sensitivity of this method is related to the fact that we observe a matter-wave interference between the excitation and the condensate, i.e., a heterodyne measurement. Expansion in the inhomogeneous Bogoliubov projection basis confirm this picture [Tozzo 2004] We estimate that this improved sensitivity should give us access to the singly quantized excitation regime. 

In conclusion we present various experimental schemes for overcoming dephasing, in order to study the intrinsic decoherence of BEC. Using some of these methods, we quantify nontrivial decoherence mechanisms both for weak excitations in BEC and in strongly excited condensates. We calculate the effects of a stronger inter-atomic interaction, namely, the appearance of a peak in the static structure factor of the system. Matter wave interference spectra are shown to be a highly sensitive probe of condensate response, with the sensitivity of this method approaching the few excitation limit. 

The increasing research on laser cooling of atoms and molecules and many experiments with Bose-Einstein condensates have brought about some remarkable results and have considerably increased our knowledge about the interaction of light with matter on a microscopic scale and the interatomic interactions at very low temperatures. Also the realization of coherent matter waves (atom lasers) and investigations of interference effects between matter waves have proved fundamental aspects of quantum mechanics. 

Davisson and Germer (1927) used a metal lattice to show that interference between matter waves takes place. De Broglie s theory was confirmed. 

FIGURE 1.5 Interference between two one-dimensional matter waves of different wavelengths. Real wave functions have been multiplied by an exponential damping factor. 

A beam of slow atoms can be manipulated in many ways. This is performed within the field of atom optics [9.445-9.447]. An atomic beam can be bent or focused using laser fields. An atomic beam can also be reflected at an optical surface using the evanescent optical field from a laser beam reflected from the other side of the surface. The atom version of the Yoimg double-slit experiment has been performed, even with monochromatic thermal atoms, showing clearly the existence of matter waves [9.448]. Beam splitters for slow atomic beams can be optically achieved to build atomic interferometers based on de Broglie wave interference. The thermal de Broglie wavelength... 

Rakitzis, T. P., S. A. Kandel, et al. (1998). Photofragment helicity caused by matter-wave interference from multiple dissociative states. Science 281, 1346. 

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