36 research outputs found

    Electric moments in molecule interferometry

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    We investigate the influence of different electric moments on the shift and dephasing of molecules in a matter wave interferometer. Firstly, we provide a quantitative comparison of two molecules that are non-polar yet polarizable in their thermal ground state and that differ in their stiffness and response to thermal excitations . While C 25 H 20 is rather rigid, its larger derivative C 49 H 16 F 52 is additionally equipped with floppy side chains and vibrationally activated dipole moment variations. Secondly, we elucidate the role of a permanent electric dipole moment by contrasting the quantum interference pattern of a (nearly) non-polar and a polar porphyrin derivative. We find that a high molecular polarizability and even sizeable dipole moment fluctuations are still well compatible with high-contrast quantum interference fringes. The presence of permanent electric dipole moments, however, can lead to a dephasing and rapid degradation of the quantum fringe pattern already at moderate electric fields. This finding is of high relevance for coherence experiments with large organic molecules, which are generally equipped with strong electric moments

    The main aspects of rail transport control system of Prague Public Transport Company

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    Tato práce popisuje systém řízení nejdůležitějších částí pražské hromadné dopravy, tj. metra a tramvají. Kromě charakteristiky a hodnocení jednotlivých řídících a zabezpečovacích systémů, jako je DORIS, LZA, ARS nebo Matra, je zde zmínka také o historickém vývoji jednotlivých subsystémů pražské hromadné dopravy a jejich současném stavu
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