2,144 research outputs found

    Charged Particles and the Electro-Magnetic Field in Non-Inertial Frames of Minkowski Spacetime: I. Admissible 3+1 Splittings of Minkowski Spacetime and the Non-Inertial Rest Frames

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    By using the 3+1 point of view and parametrized Minkowski theories we develop the theory of {\it non-inertial} frames in Minkowski space-time. The transition from a non-inertial frame to another one is a gauge transformation connecting the respective notions of instantaneous 3-space (clock synchronization convention) and of the 3-coordinates inside them. As a particular case we get the extension of the inertial rest-frame instant form of dynamics to the non-inertial rest-frame one. We show that every isolated system can be described as an external decoupled non-covariant canonical center of mass (described by frozen Jacobi data) carrying a pole-dipole structure: the invariant mass and an effective spin. Moreover we identify the constraints eliminating the internal 3-center of mass inside the instantaneous 3-spaces. In the case of the isolated system of positive-energy scalar particles with Grassmann-valued electric charges plus the electro-magnetic field we obtain both Maxwell equations and their Hamiltonian description in non-inertial frames. Then by means of a non-covariant decomposition we define the non-inertial radiation gauge and we find the form of the non-covariant Coulomb potential. We identify the coordinate-dependent relativistic inertial potentials and we show that they have the correct Newtonian limit. In the second paper we will study properties of Maxwell equations in non-inertial frames like the wrap-up effect and the Faraday rotation in astrophysics. Also the 3+1 description without coordinate-singularities of the rotating disk and the Sagnac effect will be given, with added comments on pulsar magnetosphere and on a relativistic extension of the Earth-fixed coordinate system.Comment: This paper and the second one are an adaptation of arXiv 0812.3057 for publication on Int.J.Geom. Methods in Modern Phys. 77

    Quantum power correction to the Newton law

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    We have found the graviton contribution to the one-loop quantum correction to the Newton law. This correction results in interaction decreasing with distance as 1/r^3 and is dominated numerically by the graviton contribution. The previous calculations of this contribution to the discussed effect are demonstrated to be incorrect.Comment: 10 pages, 5 figures; numerical error corrected, few references adde

    Generating branes via sigma-models

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    Starting with the D-dimensional Einstein-dilaton-antisymmetric form equations and assuming a block-diagonal form of a metric we derive a (D−d)(D-d)-dimensional σ\sigma-model with the target space SL(d,R)/SO(d)×SL(2,R)/SO(2)×RSL(d,R)/SO(d) \times SL(2,R)/SO(2) \times R or its non-compact form. Various solution-generating techniques are developed and applied to construct some known and some new pp-brane solutions. It is shown that the Harrison transformation belonging to the SL(2,R)SL(2,R) subgroup generates black pp-branes from the seed Schwarzschild solution. A fluxbrane generalizing the Bonnor-Melvin-Gibbons-Maeda solution is constructed as well as a non-linear superposition of the fluxbrane and a spherical black hole. A new simple way to endow branes with additional internal structure such as plane waves is suggested. Applying the harmonic maps technique we generate new solutions with a non-trivial shell structure in the transverse space (`matrioshka' pp-branes). It is shown that the pp-brane intersection rules have a simple geometric interpretation as conditions ensuring the symmetric space property of the target space. Finally, a Bonnor-type symmetry is used to construct a new magnetic 6-brane with a dipole moment in the ten-dimensional IIA theory.Comment: 21 pages Late

    Abelian gauge theories on compact manifolds and the Gribov ambiguity

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    We study the quantization of abelian gauge theories of principal torus bundles over compact manifolds with and without boundary. It is shown that these gauge theories suffer from a Gribov ambiguity originating in the non-triviality of the bundle of connections whose geometrical structure will be analyzed in detail. Motivated by the stochastic quantization approach we propose a modified functional integral measure on the space of connections that takes the Gribov problem into account. This functional integral measure is used to calculate the partition function, the Greens functions and the field strength correlating functions in any dimension using the fact that the space of inequivalent connections itself admits the structure of a bundle over a finite dimensional torus. The Greens functions are shown to be affected by the non-trivial topology, giving rise to non-vanishing vacuum expectation values for the gauge fields.Comment: 33 page

    CCRS proposal for evaluating LANDSAT-4 MSS and TM data

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    The measurement of registration errors in LANDSAT MSS data is discussed as well as the development of a revised algorithm for the radiometric calibration of TM data and the production of a geocoded TM image

    Dimensional reduction of 4d heterotic string black holes

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    We perform the spherical symmetric dimensional reduction 4d→2d4d\to2d of heterotic string theory. We find a class of two-dimensional (2d) dilaton gravity models that gives a general description of the near-horizon, near-extremal behavior of four-dimensional (4d) heterotic string black holes. We show that the duality group of the 4d theory is realized in two dimensions in terms of Weyl transformations of the metric. We use the 2d dilaton gravity theory to compute the statistical entropy of the near-extremal 4d, a=1/3a=1/\sqrt3, black hole.Comment: 12 pages, LaTex fil

    The holonomy of IIB supercovariant connection

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    We show that the holonomy of the supercovariant connection of IIB supergravity is contained in SL(32, \bR). We also find that the holonomy reduces to a subgroup of SL(32-N)\st (\oplus^N \bR^{32-N}) for IIB supergravity backgrounds with NN Killing spinors. We give the necessary and sufficient conditions for a IIB background to admit NN Killing spinors. A IIB supersymmetric probe configuration can involve up to 31 linearly independent planar branes and preserves one supersymmetry.Comment: 8 pages, latex. v2: Minor correction

    Consistency conditions and trace anomalies in six dimensions

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    Conformally invariant quantum field theories develop trace anomalies when defined on curved backgrounds. We study again the problem of identifying all possible trace anomalies in d=6 by studying the consistency conditions to derive their 10 independent solutions. It is known that only 4 of these solutions represent true anomalies, classified as one type A anomaly, given by the topological Euler density, and three type B anomalies, made up by three independent Weyl invariants. However, we also present the explicit expressions of the remaining 6 trivial anomalies, namely those that can be obtained by the Weyl variation of local functionals. The knowledge of the latter is in general necessary to disentangle the universal coefficients of the type A and B anomalies from calculations performed on concrete models.Comment: 16 pages, LaTe

    The Finiteness Requirement for Six-Dimensional Euclidean Einstein Gravity

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    The finiteness requirement for Euclidean Einstein gravity is shown to be so stringent that only the flat metric is allowed. We examine counterterms in 4D and 6D Ricci-flat manifolds from general invariance arguments.Comment: 15 pages, Introduction is improved, many figures(eps

    Probation, credibility and justice

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    This paper explores the difficulties that arise for probation agencies or those that deliver community sanctions in developing and maintaining their credibility in prevailing ‘late-modern’ social conditions. It begins by questioning the limits of the pursuit and promise of ‘public protection’ as a source of credibility, and then proceeds to examine the emergence of an alternative strategy – based principally on reparation and ‘payback’ – in Scotland, arguing that these Scottish developments have much to say to the emerging debates in England and Wales (and elsewhere) about the ‘rehabilitation revolution’ and the proper use of imprisonment. The paper provides a critical account of the development and meaning of the Scottish version of ‘payback’, linking it to some important philosophical and empirical studies that may help to steer the development of payback away from a ‘merely punitive’ drift. In the conclusion, I argue that probation agencies and services need to engage much more deeply and urgently with their roles as justice services, rather than as ‘mere’ crime reduction agencies
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