252,245 research outputs found

    Quantum Complex Scalar Field in the Two-Dimensional Spacetime with Closed Timelike Curves and a Time-Machine Problem

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    It is considered the quantum complex scalar field which obeys the authomorphic condition in the two-dimensional spacetime with closed timelike curves and the chronology horizon. The renormalized stress-energy tensor is obtained. It is shown that the value of the stress-energy tensor is regular at the chronology horizon for specific authomorphic parameters. Thus the particular example of field configuration is given for which the Hawking's chronology protection conjecture is violated.Comment: 21(Latex)Postscript file of the figure may be received from author, CQG-94-100

    More on the chronology of Celtic sound changes

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    Graham Isaac’s recent monograph (2007) deals with the chronology of Celtic sound changes. Remarkably, the author completely disregards the relative chronology which I published 28 years earlier (1979). In the following I shall discuss the main issues on which our views differ

    Historical and Pedagogical Chronology of the Development of Ethno-confessional Musical Education of Mennonites in the South of Ukraine (End of the 18th - Early XX Centuries)

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    Historical and chronological principles that the development of musical education of Mennonites in the South of Ukraine (from the end of the 18th century to the beginning of the 20th century) is based on were explained. With the use of archetype and historical-cultural methods of research and implementation of historical and pedagogical reconstruction, an educational-organizational criterion and its indicator (subordination of Mennonite schools) were determined. The main research problem is to maintain the integrity of the ethno-religious Mennonite group among the representatives of the titular nation with the help of spiritual music. The main result: three stages of historical and pedagogical development of musical education of Mennonites in the South of Ukraine were substantiated. The significance of the study is that the deficiency of historical and pedagogical knowledge about the spiritual music education of national minorities, which for centuries lived on Ukrainian lands and influenced the history of musical education in Ukraine, was eliminated

    On the relative chronology of Slavic accentual developments

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    Last year Georg Holzer proposed a relative chronology of accentual developments in Slavic (2005). Here I shall compare his chronology with the one I put forward earlier (1975, 1989a, 2003) and discuss the differences. For the sake of convenience, I first reproduce the relevant parts of my chronology, omitting asterisks before pre-historic Slavic forms. 1. Proto-Indo-European. 2. Dialectal Indo-European. 3. Early Balto-Slavic. During this period the characteristic lateral mobility of Balto-Slavic accent patterns came into existence. 4. Late Balto-Slavic. During this period the Balto-Slavic accent patterns obtained their final shape

    Chronology Protection in Generalized Godel Spacetime

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    The effective action of a free scalar field propagating in the generalized Godel spacetime is evaluated by the zeta-function regularization method. From the result we show that the renormalized stress energy tensor may be divergent at the chronology horizon. This gives a support to the chronology protection conjecture.Comment: Latex 6 pages, typos correcte
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