1,721,136 research outputs found
Young's experiment, Schrodinger's spread and spontaneous intrinsic decoherence
No full textThe two slits interference pattern for single particle is revisited, showing its strict relation to the free particle Schrodinger's spread and describing the optical analogy. We explicitly show the possibility that spontaneous intrinsic decoherence (SID) can destroy interference pattern and that decoherence becomes stronger at the macroscopic limit
Inhomogeneous effects in the quantum free electron laser
No full textWe include inhomogeneous effects in the quantum model of a free electron laser taking into account the initial energy spread of the electron beam. From a linear analysis, we obtain a generalized dispersion relation, from which the exponential gain can be explicitly calculated. We determine the maximum allowed initial energy spread in the quantum exponential regime and we discuss the limit of large energy spread
Mysteries, puzzles and paradoxes in quantum mechanics IV - Quantum interference phenomena
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Proceedings of the 3rd Workshop on Mysteries, Puzzles and Paradoxes in Quantum Mechanics - Gargnano, Italy, September 17-23, 2000 - Preface
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Prospettive di sviluppo dell’energia eolica in Cina
No full textAs a consequence of strong recent increases in the Chinese consumption of electric power, significant doubts about the ability to face the Chinese energy demand coming from industrial, handicraft and domestic sectors are lately arisen. The need to free itself, at least partially, from oil and coal, has created various political and economic initiatives culminated in the "Law on renewable energies" of February 28th, 2005 that will come into force on January 11th, 2006. In this context, the program of wind energy exploitation assumes particular importance, because China has abundant wind energy resources. At an estimated 23-29% capacity factor, annual potential production of electricity from wind power could be as great as 506-632 TWh. Furthermore, China has a large area of shallow sea along its eastern coastline, and preliminary estimates show that the offshore wind energy potential may be three times greater than onshore potential
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Teleportation improvement by inconclusive photon subtraction
No full textInconclusive photon subtraction (IPS) is a conditional measurement scheme to force nonlinear evolution of a given state. In IPS the input state is mixed with the vacuum in a beam splitter and then the reflected beam is revealed by on-off photodetection. When the detector clicks we have the inconclusive photon subtracted state. We show that IPS on both channels of an entangled twin beam of radiation improves the fidelity of coherent state teleportation if the energy of the incoming twin beam is below a certain threshold, which depends on the beam splitter transmissivity and the quantum efficiency of photodetectors. We show that the energy threshold diverges when the transmissivity and the efficiency approach unity and compare our results with that of previous works on conclusive photon subtraction
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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