37,640 research outputs found

    Actual versus Perceived Central Bank Transparency: The Case of the European Central Bank

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    Central banks have become more and more transparent about their monetary policy making process. In the central bank transparency lit- erature the distinction between actual and perceived central bank trans- parency is often lacking. However, as perceptions are crucial for the ac- tions of economic agents this distinction matters. A discrepancy between actual and perceived transparency may exist because of incomplete or in- correct transparency knowledge and other (psychological) factors. Even financial experts, the most important channel through which the central bank can influence the economy, might suffer from misaligned perceptions. We investigate the mismatch between actual and perceived transparency and its relevance by analyzing data of a Dutch household survey on the European Central Bank’s transparency. To benefit from higher trans- parency perceptions the European Central Bank might feel tempted to stress its transparency strengths, but hide its transparency weaknesses.Central bank transparency;Perceptions;Survey;CentERpanel;Behavioral Economics

    Modelling semantic transparency

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    We present models of semantic transparency in which the perceived trans- parency of English noun–noun compounds, and of their constituent words, is pre- dicted on the basis of the expectedness of their semantic structure. We show that such compounds are perceived as more transparent when the first noun is more frequent, hence more expected, in the language generally; when the compound semantic rela- tion is more frequent, hence more expected, in association with the first noun; and when the second noun is more productive, hence more expected, as the second ele- ment of a noun–noun compound. Taken together, our models of compound and con- stituent transparency lead us to two conclusions. Firstly, although compound trans- parency is a function of the transparencies of the constituents, the two constituents differ in the nature of their contribution. Secondly, since all the significant predictors in our models of compound transparency are also known predictors of processing speed, perceived transparency may itself be a reflex of ease of processing

    Chaos-induced transparency in an ultrahigh-Q optical microcavity

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    We demonstrate experimentally a new form of induced transparency, i.e., chaos-induced transparency, in a slightly deformed microcavity which support both continuous chaotic modes and discrete regular modes with Q factors exceeding 3X?10^7. When excited by a focused laser beam, the induced transparency in the transmission spectrum originates from the destructive interference of two parallel optical pathways: (i) directly refractive excitation of the chaotic modes, and (ii) excitation of the ultra-high-Q regular mode via chaos-assisted dynamical tunneling mechanism coupling back to the chaotic modes. By controlling the focal position of the laser beam, the induced transparency experiences a highly tunable Fano-like asymmetric lineshape. The experimental results are modeled by a quantum scattering theory and show excellent agreement. This chaos-induced transparency is accompanied by extremely steep normal dispersion, and may open up new possibilities a dramatic slow light behavior and a significant enhancement of nonlinear interactions.Comment: 5 pages, 5 figue

    Multi-Transparency Windows and Fano interference Induced by Dipole-Dipole Couplings

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    We investigate the optical properties of a two-level system (TLS) coupled to a linear series of NN other TLS's with dipole-dipole coupling between the first neighbours. The first TLS is probed by weak field and we assume that it has a decay rate much stronger than the decay rates of the other TLS's. For N=1 and in the limit of a probe field much weaker than the dipole-dipole coupling, the optical response of the first TLS, i.e., its absorption and dispersion, are equivalent to those of a three-level atomic system in the configuration which allow one to observe electromagnetically induced transparency (EIT) phenomenon. Thus, here we are investigating a new kind of induced transparency where the dipole-dipole coupling plays the same role of the control field in EIT in three-level atoms. We describe this physical phenomenon, here named as Dipole-Dipole Induced Transparency (DDIT), and investigate how it scales with the number of coupled TLS's. In particular we have shown that the number of TLS's coupled to the main one is exactly equals to the number of transparency windows. The ideas presented here are very general and can be implemented in different physical systems such as array of superconducting qubits, array of quantum dots, spin chains, optical lattices, etc.Comment: 14 pages including the supplementary material and 5 figure

    Absence of split pairs in the cross-correlations of a highly transparent normal metal-superconductor-normal metal electron beam splitter

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    The nonlocal conductance and the current cross-correlations are investigated within scattering theory for three-terminal normal metal-superconductor-normal metal (NSN) hybrid structures. The positive cross-correlations at high transparency found by M\'elin, Benjamin and Martin [Phys. Rev. B 77, 094512 (2008)] are not due to crossed Andreev reflection. On the other hand, local processes can be enhanced by reflectionless tunneling but this mechanism has little influence on nonlocal processes and on current cross-correlations. Therefore Cooper pair splitting cannot be enhanced by reflectionless tunneling. Overall, this shows that NSN structures with highly transparent or effectively highly transparent interfaces are not suited to experimentally producing entangled split pairs of electrons.Comment: 11 pages, 6 figures, 1 table. arXiv admin note: substantial text overlap with arXiv:1211.534

    Waveplate retarders based on overhead transparencies

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    We describe procedures for constructing inexpensive waveplates of desired retardation out of ordinary commercially available transparencies. Various relevant properties of the transparencies are investigated: the dependence of retardation on rotation of the film, tilt, wavelength, position, and temperature. Constructing waveplates out of combinations of transparency sheets is also explored.Comment: 7 pages, 12 fig

    Bridging the gap between passivity and transparency

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    In this paper a structure will be given which in a remarkably simple way offers a solution to the implementation of different telemanipulation schemes for discrete time varying delays by preserving passivity and allowing the highest trans- parency possible. This is achieved by splitting the communication channel in two separate ones, one for the energy balance which will ensure passivity and one for the haptic information between master and slave and which will address transparency. The authors believe that this structure is the most general up to date which preserves passivity under discrete time varying delays allowing different control schemes to address transparency

    Isotropic magnetometry with simultaneous excitation of orientation and alignment CPT resonances

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    Atomic magnetometers have very high absolute precision and sensitivity to magnetic fields but suffer from a fundamental problem: the vectorial or tensorial interaction of light with atoms leads to "dead zones", certain orientations of magnetic field where the magnetometer loses its sensitivity. We demonstrate a simple polarization modulation scheme that simultaneously creates coherent population trapping (CPT) in orientation and alignment, thereby eliminating dead zones. Using 87^{87}Rb in a 10 Torr buffer gas cell we measure narrow, high-contrast CPT transparency peaks in all orientations and also show absence of systematic effects associated with non-linear Zeeman splitting.Comment: 4 pages, 4 figure
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