12,654 research outputs found

    Electromagnetic Zero Point Field as Active Energy Source in the Intergalactic Medium

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    For over twenty years the possibility that the electromagnetic zero point field (ZPF) may actively accelerate electromagnetically interacting particles in regions of extremely low particle density (as those extant in intergalactic space (IGS) with n < 1 particle/m^3 has been studied and analyzed. This energizing phenomenon has been one of the few contenders for acceleration of cosmic rays (CR), particularly at ultrahigh energies. The recent finding by the AGASA collaboration (Phys. Rev. Lett., 81, 1163, 1998) that the CR energy spectrum does not display any signs of the Greisen-Zatsepin-Kuzmin cut-off (that should be present if these CR particles were indeed generated in localized ultrahigh energies CR sources, as e.g., quasars and other highly active galactic nuclei), may indicate the need for an acceleration mechanism that is distributed throughout IGS as is the case with the ZPF. Other unexplained phenomena that receive an explanation from this mechanism are the generation of X-ray and gamma-ray backgrounds and the existence of Cosmic Voids. However recently, a statistical mechanics kind of challenge to the classical (not the quantum) version of the zero-point acceleration mechanism has been posed (de la Pena and Cetto, The Quantum Dice, 1996). Here we briefly examine the consequences of this challenge and a prospective resolution.Comment: 7 pages, no figure

    Supermembrane with Non-Abelilan Gauging and Chern-Simons Quantization

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    We present non-Abelian gaugings of supermembrane for general isometries for compactifications from eleven-dimensions, starting with Abelian case as a guide. We introduce a super Killing vector in eleven-dimensional superspace for a non-Abelian group G associated with the compact space B for a general compactification, and couple it to a non-Abelian gauge field on the world-volume. As a technical tool, we use teleparallel superspace with no manifest local Lorentz covariance. Interestingly, the coupling constant is quantized for the non-Abelian group G, due to its generally non-trivial mapping \pi_3(G).Comment: 16 pages, no figures. The content has been considerably changed with non-Abelian generalizatio

    Spacetime Defects: von K\'arm\'an vortex street like configurations

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    A special arrangement of spinning strings with dislocations similar to a von K\'arm\'an vortex street is studied. We numerically solve the geodesic equations for the special case of a test particle moving along twoinfinite rows of pure dislocations and also discuss the case of pure spinning defects.Comment: 9 pages, 2figures, CQG in pres

    Perturbation Theory for Antisymmetric Tensor Fields in Four Dimensions

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    Perturbation theory for a class of topological field theories containing antisymmetric tensor fields is considered. These models are characterized by a supersymmetric structure which allows to establish their perturbative finiteness.Comment: 23 page

    Probing the intrinsic state of a one-dimensional quantum well with a photon-assisted tunneling

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    The photon-assisted tunneling (PAT) through a single wall carbon nanotube quantum well (QW) under influence an external electromagnetic field for probing of the Tomonaga Luttinger liquid (TLL) state is suggested. The elementary TLL excitations inside the quantum well are density (ρ±\rho_{\pm}) and spin (σ±\sigma_{\pm} ) bosons. The bosons populate the quantized energy levels ϵnρ+=Δn/g\epsilon^{\rho +}_n =\Delta n/ g and ϵnρ(σ±)=Δn\epsilon^{\rho -(\sigma \pm)}_n = \Delta n where Δ=hvF/L\Delta = h v_F /L is the interlevel spacing, nn is an integer number, LL is the tube length, gg is the TLL parameter. Since the electromagnetic field acts on the ρ+\rho_{+} bosons only while the neutral ρ\rho_{-} and σ±\sigma_{\pm} bosons remain unaffected, the PAT spectroscopy is able of identifying the ρ+\rho_{+} levels in the QW setup. The spin ϵnσ+\epsilon_n^{\sigma+} boson levels in the same QW are recognized from Zeeman splitting when applying a d.c. magnetic field H0H \neq 0 field. Basic TLL parameters are readily extracted from the differential conductivity curves.Comment: 10 pages, 5 figure

    Tracing CP-violation in Lepton Flavor Violating Muon Decays

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    Although the Lepton Flavor Violating (LFV) decay μ+e+γ\mu^+\to e^+ \gamma is forbidden in the Standard Model (SM), it can take place within various theories beyond the SM. If the branching ratio of this decay saturates its present bound [{\it i.e.,} Br(μ+e+γ)1011(\mu^+ \to e^+\gamma)\sim 10^{-11}], the forthcoming experiments can measure the branching ratio with high precision and consequently yield information on the sources of LFV. In this letter, we show that for polarized μ+\mu^+, by studying the angular distribution of the transversely polarized positron and linearly polarized photon we can derive information on the CP-violating sources beyond those in the SM. We also study the angular distribution of the final particles in the decay μ+e1+ee2+\mu^+\to e^+_1 e^- e^+_2 where e1+e^+_1 is defined to be the more energetic positron. We show that transversely polarized e1+e_1^+ can provide information on a certain combination of the CP-violating phases of the underlying theory which would be lost by averaging over the spin of e1+e^+_1.Comment: 6 pages, 2 figure

    Instanton Floer homology and the Alexander polynomial

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    The instanton Floer homology of a knot in the three-sphere is a vector space with a canonical mod 2 grading. It carries a distinguished endomorphism of even degree,arising from the 2-dimensional homology class represented by a Seifert surface. The Floer homology decomposes as a direct sum of the generalized eigenspaces of this endomorphism. We show that the Euler characteristics of these generalized eigenspaces are the coefficients of the Alexander polynomial of the knot. Among other applications, we deduce that instanton homology detects fibered knots.Comment: 25 pages, 6 figures. Revised version, correcting errors concerning mod 2 gradings in the skein sequenc

    Reframing Kurtz’s Painting: Colonial Legacies and Minority Rights in Ethnically Divided Societies

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    Minority rights constitute some of the most normatively and economically important human rights. Although the political science and legal literatures have proffered a number of constitutional and institutional design solutions to address the protection of minority rights, these solutions are characterized by a noticeable neglect of, and lack of sensitivity to, historical processes. This Article addresses that gap in the literature by developing a causal argument that explains diverging practices of minority rights protections as functions of colonial governments’ variegated institutional practices with respect to particular ethnic groups. Specifically, this Article argues that in instances where colonial governments politicize and institutionalize ethnic hegemony in the pre-independence period, an institutional legacy is created that leads to lower levels of minority rights protections. Conversely, a uniform treatment and depoliticization of ethnicity prior to independence ultimately minimizes ethnic cleavages post-independence and consequently causes higher levels of minority rights protections. Through a highly structured comparative historical analysis of Botswana and Ghana, this Article builds on a new and exciting research agenda that focuses on the role of long-term historio-structural and institutional influences on human rights performance and makes important empirical contributions by eschewing traditional methodologies that focus on single case studies that are largely descriptive in their analyses. Ultimately, this Article highlights both the strength of a historical approach to understanding current variations in minority rights protections and the varied institutional responses within a specific colonial government
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