920 research outputs found

    Morphological Image Analysis of Quantum Motion in Billiards

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    Morphological image analysis is applied to the time evolution of the probability distribution of a quantum particle moving in two and three-dimensional billiards. It is shown that the time-averaged Euler characteristic of the probability density provides a well defined quantity to distinguish between classically integrable and non-integrable billiards. In three dimensions the time-averaged mean breadth of the probability density may also be used for this purpose.Comment: Major revision. Changes include a more detailed discussion of the theory and results for 3 dimensions. Now: 10 pages, 9 figures (some are colored), 3 table

    Low-frequency acoustic optimization of a double-wall panel by means of vibration absorbers

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    Assessing Unilateral Merger Effects in a Two-Sided Market: An Application to the Dutch Daily Newspaper Market

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    We compare different methods to assess unilateral merger effects in a two-sided market by applying them to a hypothetical merger in the Dutch newspaper industry. For this, we first specify and estimate a structural model of demand for differentiated products on both the readership and the advertising side of the market. This allows us to recover price elasticities and indirect network effects. Following Filistrucchi, Klein, and Michielsen (2010) marginal costs are then recovered from an oligopoly model of the supply side. We use these estimates of price elasticities, network effects and marginal costs to compare different methods that can be used to evaluate merger effects: We perform a concentration analysis based on the Herfindahl Hirschmann Index, a Small Significant Non-Transitory Increase in Price test, measure Upward Pricing Pressure, and conduct a full merger simulation.Two-sided markets, newspapers, advertising, network effects, merger simulation, SSNIP, UPP, HHI.

    Real-time broadening of non-equilibrium density profiles and the role of the specific initial-state realization

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    The real-time broadening of density profiles starting from non-equilibrium states is at the center of transport in condensed-matter systems and dynamics in ultracold atomic gases. Initial profiles close to equilibrium are expected to evolve according to linear response, e.g., as given by the current correlator evaluated exactly at equilibrium. Significantly off equilibrium, linear response is expected to break down and even a description in terms of canonical ensembles is questionable. We unveil that single pure states with density profiles of maximum amplitude yield a broadening in perfect agreement with linear response, if the structure of these states involves randomness in terms of decoherent off-diagonal density-matrix elements. While these states allow for spin diffusion in the XXZ spin-1/2 chain at large exchange anisotropies, coherences yield entirely different behavior.Comment: 7 pages, 7 figures, accepted for publication in Phys. Rev.

    Eigenstate Thermalization Hypothesis and Quantum Jarzynski Relation for Pure Initial States

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    Since the first suggestion of the Jarzynski equality many derivations of this equality have been presented in both, the classical and the quantum context. While the approaches and settings greatly differ from one to another, they all appear to rely on the initial state being a thermal Gibbs state. Here, we present an investigation of work distributions in driven isolated quantum systems, starting off from pure states that are close to energy eigenstates of the initial Hamiltonian. We find that, for the nonintegrable system in quest, the Jarzynski equality is fulfilled to good accuracy.Comment: 9 pages, 7 figure

    Possible Experience: from Boole to Bell

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    Mainstream interpretations of quantum theory maintain that violations of the Bell inequalities deny at least either realism or Einstein locality. Here we investigate the premises of the Bell-type inequalities by returning to earlier inequalities presented by Boole and the findings of Vorob'ev as related to these inequalities. These findings together with a space-time generalization of Boole's elements of logic lead us to a completely transparent Einstein local counterexample from everyday life that violates certain variations of the Bell inequalities. We show that the counterexample suggests an interpretation of the Born rule as a pre-measure of probability that can be transformed into a Kolmogorov probability measure by certain Einstein local space-time characterizations of the involved random variables.Comment: Published in: EPL, 87 (2009) 6000

    Merger Simulation in a Two-Sided Market: The Case of the Dutch Daily Newspapers

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    We develop a structural econometric framework that allows us to simulate the effects of mergers among two-sided platforms selling differentiated products. We apply the proposed methodology to the Dutch newspaper industry. Our structural model encompasses demands for differentiated products on both sides of the market and profit maximization by competing oligopolistic publishers who choose subscription and advertising prices, while taking the interactions between the two-sides of the market into account. We measure the sign and size of the indirect network effects between the two sides of the market and simulate the effects of a hypothetical merger on prices and welfare
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