44 research outputs found

    The sources of British economic growth since the industrial revolution: not the same old story

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    This paper updates the classic growth accounting research of the early 1980s taking account of improved data that has subsequently become available. The picture of long-run growth which results from incorporating many revisions is considerably different. The long-run path of productivity growth is now that of a roller-coaster with twin peaks in the third quarters of the 19th and 20th centuries rather than a U-shape. Productivity growth appears to have been very slow to accelerate in the Industrial Revolution, the notion of an Edwardian climacteric is not persuasive and the current productivity slowdown stands out as unprecedented

    Sequential, successive, and simultaneous decoders for entanglement-assisted classical communication

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    Bennett et al. showed that allowing shared entanglement between a sender and receiver before communication begins dramatically simplifies the theory of quantum channels, and these results suggest that it would be worthwhile to study other scenarios for entanglement-assisted classical communication. In this vein, the present paper makes several contributions to the theory of entanglement-assisted classical communication. First, we rephrase the Giovannetti-Lloyd-Maccone sequential decoding argument as a more general "packing lemma" and show that it gives an alternate way of achieving the entanglement-assisted classical capacity. Next, we show that a similar sequential decoder can achieve the Hsieh-Devetak-Winter region for entanglement-assisted classical communication over a multiple access channel. Third, we prove the existence of a quantum simultaneous decoder for entanglement-assisted classical communication over a multiple access channel with two senders. This result implies a solution of the quantum simultaneous decoding conjecture for unassisted classical communication over quantum multiple access channels with two senders, but the three-sender case still remains open (Sen recently and independently solved this unassisted two-sender case with a different technique). We then leverage this result to recover the known regions for unassisted and assisted quantum communication over a quantum multiple access channel, though our proof exploits a coherent quantum simultaneous decoder. Finally, we determine an achievable rate region for communication over an entanglement-assisted bosonic multiple access channel and compare it with the Yen-Shapiro outer bound for unassisted communication over the same channel.Comment: 33 pages, 2 figures; v2 contains a proof of the quantum simultaneous decoding conjecture for two-sender quantum multiple access channels; v3 shows how to recover the known unassisted and assisted quantum communication regions with a coherent quantum simultaneous decode

    Cosmology With Non-Minimally Coupled K-Field

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    We consider non-minimally coupled (with gravity) scalar field with non-canonical kinetic energy. The form of the kinetic term is of Dirac-Born-Infeld (DBI) form.We study the early evolution of the universe when it is sourced only by the k-field, as well as late time evolution when both the matter and k-field are present. For the k-field, we have considered constant potential as well as potential inspired from Boundary String Field Theory (B-SFT). We show that it is possible to have inflationary solution in early time as well as late time accelerating phase. The solutions also exhibit attractor property in a sense that it does not depend on the initial conditions for a certain values of the parameters.Comment: 10 pages, Revtex style, 14 eps figures, to appear in General Relativity and Gravitatio

    Growth accounting in economic history:Findings, lessons and new directions

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    There is now a large volume of growth accounting estimates covering the long run experience of advanced countries. However, most of the studies in economic history are not based on state-of-the-art methods. There is a trade-off between maintaining international comparability and achieving the best results for individual countries. A one-size-fits-all approach will not always do justice to the variety of historical experiences since the conventional assumptions may sometimes be inappropriate. Nevertheless, growth-accounting studies have produced some eye-catching results which provide food for thought both for economic historians and for growth economists. These include (1) the finding that TFP growth was comparatively slow during the First Industrial Revolution, (2) Solow's famous conclusion that TFP growth accounted for 7/8ths of American labour-productivity growth was atypical, (3) the impact of new general-purpose technologies on growth typically takes a long time to materialize, ICT being the notable exception and (4) that capital-deepening was much more important relative to TFP growth in east Asian than in western European catch-up growth. Growth accounting is undoubtedly a valuable item in the cliometrician's toolkit. Nonetheless, we anticipate the introduction of more sophisticated methods and look forward to progress in understanding what explains marked differences in TFP performance

    Performance of the front-end electronics of the ANTARES neutrino telescope

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    ANTARES is a high-energy neutrino telescope installed in the Mediterranean Sea at a depth of 2475 m. It consists of a three-dimensional array of optical modules, each containing a large photomultiplier tube. A total of 2700 front-end ASICs named Analogue Ring Samplers (ARS) process the phototube signals, measure their arrival time, amplitude and shape as well as perform monitoring and calibration tasks. The ARS chip processes the analogue signals from the optical modules and converts information into digital data. All the information is transmitted to shore through further multiplexing electronics and an optical link. This paper describes the performance of the ARS chip; results from the functionality and characterization tests in the laboratory are summarized and the long-term performance in the apparatus is illustrated.Comment: 20 pages, 22 figures, published in Nuclear Instruments and Methods

    A plea for errors

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    SIGLEAvailable from British Library Document Supply Centre-DSC:3597.9143(no 41) / BLDSC - British Library Document Supply CentreGBUnited Kingdo
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