4,647 research outputs found

    Remarks on twisted noncommutative quantum field theory

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    We review recent results on twisted noncommutative quantum field theory by embedding it into a general framework for the quantization of systems with a twisted symmetry. We discuss commutation relations in this setting and show that the twisted structure is so rigid that it is hard to derive any predictions, unless one gives up general principles of quantum theory. It is also shown that the twisted structure is not responsible for the presence or absence of UV/IR-mixing, as claimed in the literature.Comment: 13 pages, v2: minor correction

    A Robust Measure of Tidal Circularization in Coeval Binary Populations: The solar-type spectroscopic Binary Population in The Open Cluster M35

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    We present a new homogeneous sample of 32 spectroscopic binary orbits in the young (~ 150 Myr) main-sequence open cluster M35. The distribution of orbital eccentricity vs. orbital period (e-log(P)) displays a distinct transition from eccentric to circular orbits at an orbital period of ~ 10 days. The transition is due to tidal circularization of the closest binaries. The population of binary orbits in M35 provide a significantly improved constraint on the rate of tidal circularization at an age of 150 Myr. We propose a new and more robust diagnostic of the degree of tidal circularization in a binary population based on a functional fit to the e-log(P) distribution. We call this new measure the tidal circularization period. The tidal circularization period of a binary population represents the orbital period at which a binary orbit with the most frequent initial orbital eccentricity circularizes (defined as e = 0.01) at the age of the population. We determine the tidal circularizationperiod for M35 as well as for 7 additional binary populations spanning ages from the pre main-sequence (~ 3 Myr) to late main-sequence (~ 10 Gyr), and use Monte Carlo error analysis to determine the uncertainties on the derived circularization periods. We conclude that current theories of tidal circularization cannot account for the distribution of tidal circularization periods with population age.Comment: 37 pages, 9 figures, to be published in The Astrophysical Journal, February 200

    Dynamical Tide in Solar-Type Binaries

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    Circularization of late-type main-sequence binaries is usually attributed to turbulent convection, while that of early-type binaries is explained by resonant excitation of g modes. We show that the latter mechanism operates in solar-type stars also and is at least as effective as convection, despite inefficient damping of g modes in the radiative core. The maximum period at which this mechanism can circularize a binary composed of solar-type stars in 10 Gyr is as low as 3 days, if the modes are damped by radiative diffusion only and g-mode resonances are fixed; or as high as 6 days, if one allows for evolution of the resonances and for nonlinear damping near inner turning points. Even the larger theoretical period falls short of the observed transition period by a factor two.Comment: 17 pages, 2 postscript figures, uses aaspp4.sty. Submitted to Ap

    Seismic tests for solar models with tachocline mixing

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    We have computed accurate 1-D solar models including both a macroscopic mixing process in the solar tachocline as well as up-to-date microscopic physical ingredients. Using sound speed and density profiles inferred through primary inversion of the solar oscillation frequencies coupled with the equation of thermal equilibrium, we have extracted the temperature and hydrogen abundance profiles. These inferred quantities place strong constraints on our theoretical models in terms of the extent and strength of our macroscopic mixing, on the photospheric heavy elements abundance, on the nuclear reaction rates such as S11S_{11} and S34S_{34} and on the efficiency of the microscopic diffusion. We find a good overall agreement between the seismic Sun and our models if we introduce a macroscopic mixing in the tachocline and allow for variation within their uncertainties of the main physical ingredients. From our study we deduce that the solar hydrogen abundance at the solar age is Xinv=0.732±0.001X_{\rm inv}=0.732\pm 0.001 and that based on the 9^9Be photospheric depletion, the maximum extent of mixing in the tachocline is 5% of the solar radius. The nuclear reaction rate for the fundamental pppp reaction is found to be S11(0)=4.06±0.07S_{11}(0)=4.06\pm 0.07 102510^{-25} MeV barns, i.e., 1.5% higher than the present theoretical determination. The predicted solar neutrino fluxes are discussed in the light of the new SNO/SuperKamiokande results.Comment: 16 pages, 12 figures, A&A in press (1) JILA, University of Colorado, Boulder, CO 80309-0440, USA, (2) LUTH, Observatoire de Paris-Meudon, 92195 Meudon, France, (3) Tata Institute of Fundamental Research, Homi Bhabha road, Mumbai 400005, India, (4) Department of Physics, University of Mumbai, Mumbai 400098, Indi

    Delensing CMB Polarization with External Datasets

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    One of the primary scientific targets of current and future CMB polarization experiments is the search for a stochastic background of gravity waves in the early universe. As instrumental sensitivity improves, the limiting factor will eventually be B-mode power generated by gravitational lensing, which can be removed through use of so-called delensing algorithms. We forecast prospects for delensing using lensing maps which are obtained externally to CMB polarization: either from large-scale structure observations, or from high-resolution maps of CMB temperature. We conclude that the forecasts in either case are not encouraging, and that significantly delensing large-scale CMB polarization requires high-resolution polarization maps with sufficient sensitivity to measure the lensing B-mode. We also present a simple formalism for including delensing in CMB forecasts which is computationally fast and agrees well with Monte Carlos.Comment: typos correcte

    The Problem of Characterizing the 4QReworked Pentateuch Manuscripts: Bible, Rewritten Bible, or None of the Above?

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    This is the author's accepted manuscript. The original is available at http://booksandjournals.brillonline.com/content/journals/10.1163/156851708x304895This article engages the problem of whether the five manuscripts classified as 4QReworked Pentateuch (4Q158, 4Q364–367) should be considered extrabiblical compositions or simply expansive copies of the Pentateuch. Since similar methods of reworking scripture appear in both types of text, focusing on the ways scripture is reworked in the 4QRP manuscripts cannot solve the problem. Other criteria such as the literary voice, scope, and coverage of a work are more promising. The fragmentary state of the texts, however, precludes a definitive solution and requires that multiple possibilities be considered

    The Samaritan Pentateuch and the Scribal Culture of Second Temple Judaism

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    This is the author's accepted manuscript. The original is available at http://booksandjournals.brillonline.com/content/journals/10.1163/15700631-12340103The Samaritan Pentateuch (SP), along with its Qumran forebears, has deservedly been regarded as a key source of information for understanding the scribal culture of early Judaism. Yet studies have tended to emphasize the relative uniformity of the characteristic pre-SP readings as evidence of a scribal approach distinct within Second Temple Judaism. This article argues that both the uniformity and the distinctiveness of these readings have been overstated: there is more internal diversity within pre-SP than is usually recognized, and similar or identical readings are also preserved in other manuscript traditions. Rather than representing a distinctive scribal approach or school, the readings of pre-SP are better taken as a particularly concentrated example of scribal attitudes and techniques that appear to have been widespread in early Judaism

    4QReworked Pentateuch C and the Literary Sources of the Temple Scroll: A New (Old) Proposal

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    This is the author's accepted manuscript. The original is available at http://booksandjournals.brillonline.com/content/journals/10.1163/156851712x644622This essay proposes a new understanding of the literary history of the Temple Scroll in light of its relationship with 4QReworked Pentateuch C (4Q365 + 365a). It begins from the argument that 4QRP C includes the five fragments labeled 4Q365a (4QTemple?), and that 4QRP C should be regarded as an expanded edition of the Pentateuch. Substantial parallels between 4QRP C (both 4Q365 and 4Q365a) and the Temple Scroll raise the possibility that an expanded Pentateuch resembling 4QRP C could have constituted the main source with which the Temple Scroll’s redactor worked. This proposal departs from the usual understanding of the Scroll as comprised of several lightly-reworked, independent sources. Instead, it situates the composition of the Temple Scroll more firmly in the context of the ongoing scribal reworking of scripture in the Second Temple period
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