10,024 research outputs found

    Covariance of Time-Ordered Products Implies Local Commutativity of Fields

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    We formulate Lorentz covariance of a quantum field theory in terms of covariance of time-ordered products (or other Green's functions). This formulation of Lorentz covariance implies spacelike local commutativity or anticommutativity of fields, sometimes called microscopic causality or microcausality. With this formulation microcausality does not have to be taken as a separate assumption.Comment: 6 pages, section on non-local theories removed, published versio

    CPT Violation Implies Violation of Lorentz Invariance

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    An interacting theory that violates CPT invariance necessarily violates Lorentz invariance. On the other hand, CPT invariance is not sufficient for out-of-cone Lorentz invariance. Theories that violate CPT by having different particle and antiparticle masses must be nonlocal.Comment: Minor changes in the published versio

    String Gas Baryogenesis

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    We describe a possible realization of the spontaneous baryogenesis mechanism in the context of extra-dimensional string cosmology and specifically in the string gas scenario.Comment: arXiv admin note: substantial text overlap with 0808.0746 by different autho

    Analytical results for O(\alpha_s) radiative corrections to e+ e- -> tbar t(pol.) up to a given gluon energy cut

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    We determine the O(\alpha_s) radiative corrections to polarized top quark pair production in e+ e- -annihilations with a specified gluon energy cut. We write down fully analytical results for the unpolarized and polarized O(\alpha_s) cross sections e+ e- -> tbar t (G) and e+ e- -> tbar t(pol.) (G) including their polar orientation dependence relative to the beam direction. In the soft gluon limit we recover the usual factorizing form known from the soft gluon approximation. In the limit when the gluon energy cut takes its maximum value we recover the totally inclusive unpolarized and polarized cross sections calculated previously. We provide some numerical results on the cut-off dependence of the various polarized and unpolarized cross sections and discuss how the exact results numerically differ from the approximate soft-gluon results.Comment: 49 pages in LaTeX, including 17 encapsulated PostScript figure

    Why is CPT fundamental?

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    G. L\"uders and W. Pauli proved the CPT\mathcal{CPT} theorem based on Lagrangian quantum field theory almost half a century ago. R. Jost gave a more general proof based on ``axiomatic'' field theory nearly as long ago. The axiomatic point of view has two advantages over the Lagrangian one. First, the axiomatic point of view makes clear why CPT\mathcal{CPT} is fundamental--because it is intimately related to Lorentz invariance. Secondly, the axiomatic proof gives a simple way to calculate the CPT\mathcal{CPT} transform of any relativistic field without calculating C\mathcal{C}, P\mathcal{P} and T\mathcal{T} separately and then multiplying them. The purpose of this pedagogical paper is to ``deaxiomatize'' the CPT\mathcal{CPT} theorem by explaining it in a few simple steps. We use theorems of distribution theory and of several complex variables without proof to make the exposition elementary.Comment: 17 pages, no figure

    The Liturgical Communion of the Yaḥad with the Angels. The Origin of the Songs of the Sabbath Sacrifice Reconsidered

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    Since the discoveries of the first Dead Sea Scrolls, the motif of a communion with the angels has been repeatedly emphasized and discussed as a characteristic of the self-understanding of the community behind these writings. Of particular interest in this discussion are the Songs of the Sabbath Sacrifice (4Q400–407; 11Q17; and Mas1k ShirShabb). However, the origin of the so-called Angelic Liturgy is still an unresolved question in scholarship. In this article we will try to figure out the relationship of the Songs of the Sabbath Sacrifice to the sectarian literature by analyzing the communion with the angels described therein. I will demonstrate that this composition has the most explicit connections to the liturgical communion with the angels that is uniquely found in undisputed sectarian texts. The Angelic Liturgy is then not so much the source, but much more an example of the liturgical development inside the yaḥad

    KMS, etc

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    A general form of the ``Wick rotation'', starting from imaginary-time Green functions of quantum-mechanical systems in thermal equilibrium at positive temperature, is established. Extending work of H. Araki, the role of the KMS condition and of an associated anti-unitary symmetry operation, the ``modular conjugation'', in constructing analytic continuations of Green functions from real- to imaginary times, and back, is clarified. The relationship between the KMS condition for the vacuum with respect to Lorentz boosts, on one hand, and the spin-statistics connection and the PCT theorem, on the other hand, in local, relativistic quantum field theory is recalled. General results on the reconstruction of local quantum theories in various non-trivial gravitational backgrounds from ``Euclidian amplitudes'' are presented. In particular, a general form of the KMS condition is proposed and applied, e.g., to the Unruh- and the Hawking effects. This paper is dedicated to Huzihiro Araki on the occasion of his seventieth birthday, with admiration, affection and best wishes.Comment: 56 pages, submitted to J. Math. Phy

    Comparative Morphology of the Penis and Clitoris in Four Species of Moles (Talpidae).

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    The penile and clitoral anatomy of four species of Talpid moles (broad-footed, star-nosed, hairy-tailed, and Japanese shrew moles) were investigated to define penile and clitoral anatomy and to examine the relationship of the clitoral anatomy with the presence or absence of ovotestes. The ovotestis contains ovarian tissue and glandular tissue resembling fetal testicular tissue and can produce androgens. The ovotestis is present in star-nosed and hairy-tailed moles, but not in broad-footed and Japanese shrew moles. Using histology, three-dimensional reconstruction, and morphometric analysis, sexual dimorphism was examined with regard to a nine feature masculine trait score that included perineal appendage length (prepuce), anogenital distance, and presence/absence of bone. The presence/absence of ovotestes was discordant in all four mole species for sex differentiation features. For many sex differentiation features, discordance with ovotestes was observed in at least one mole species. The degree of concordance with ovotestes was highest for hairy-tailed moles and lowest for broad-footed moles. In relationship to phylogenetic clade, sex differentiation features also did not correlate with the similarity/divergence of the features and presence/absence of ovotestes. Hairy-tailed and Japanese shrew moles reside in separated clades, but they exhibit a high degree of congruence. Broad-footed and hairy-tailed moles reside within the same clade but had one of the lowest correlations in features and presence/absence of ovotestes. Thus, phylogenetic affinity and the presence/absence of ovotestes are poor predictors for most sex differentiation features within mole external genitalia
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