412 research outputs found

    Supersymmetric FRW model and the ground state of supergravity

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    In this work we construct the vacuum configuration of supergravity interacting with homogeneous complex scalar matter fields. The corresponding configuration is of the FRW model invariant under the n=2n=2 local conformal time supersymmetry, which is a subgroup of the four dimensional space-time supersymmetry. We show, that the potential of the scalar matter fields is a function of the K\"ahler potential and of the arbitrary parameter α\alpha. This parameter enumerates the vacuum states. The scalar matter potential induces the spontaneous breaking of supersymmetry in supergravity. On the quantum level our model is a specific supersymmetric quantum mechanics, which admits quantum states in supergravity, and the states with zero energy are described by the wave function of the FRW universe.Comment: 18 pages, Revtex, submitted to PR

    On the relation of the gravitino mass and the GUT parameters

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    In this article we consider the local supersymmetry breaking and the broken SU(5) symmetry permisible by dilaton vacuum configuration in supergravity theories. We establish the parameter relation of spontaneuos breaking of supersymmetry and of the GUT theory.Comment: 12 pages, file written in Revtex forma

    BRST Algebra Quantum Double and Quantization of the Proper Time Cotangent Bundle

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    The quantum double for the quantized BRST superalgebra is studied. The corresponding R-matrix is explicitly constucted. The Hopf algebras of the double form an analytical variety with coordinates described by the canonical deformation parameters. This provides the possibility to construct the nontrivial quantization of the proper time supergroup cotangent bundle. The group-like classical limit for this quantization corresponds to the generic super Lie bialgebra of the double.Comment: 11 pages, LaTe

    Electron spin resonance investigation of Mn^{2+} ions and their dynamics in manganese doped SrTiO_3

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    Using electron spin resonance, lattice position and dynamic properties of Mn2+ ions were studied in 0.5 and 2 % manganese doped SrTiO3 ceramics prepared by conventional mixed oxide method. The measurements showed that Mn2+ ions substitute preferably up to 97 % for Sr if the ceramics is prepared with a deficit of Sr ions. Motional narrowing of the Mn2+ ESR spectrum was observed when temperature increases from 120 K to 240-250 K that was explained as a manifestation of off-center position of this ion at the Sr site. From the analysis of the ESR spectra the activation energy Ea = 86 mV and frequency factor 1/?0 ? (2-10)x10^(-14) 1/s for jumping of the impurity between symmetrical off-center positions were determined. Both values are in agreement with those derived previously from dielectric relaxation. This proves the origin of dielectric anomalies in SrTiO3:Mn as those produced by the reorientation dynamics of Mn2+ dipoles.Comment: 16 pages, 6 figure

    Rheological parameters of the water-saturated clay soils on the theory of aging

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    Розглянуті реологічні зміни перезволожених глинистих грунтів при компресійному стисненні та співставленні з класичними теоріями фільтраційної консолідації Терцагі-Герсеванова. Встановлено, що коефіцієнти відносного стиснення mvi при різних факторах часу ti суттєво збільшуються. Збільшення коефіцієнта mvi виникає під час завершення консолідаційної фільтрації tf. При співставленні зміни порових тисків uw та осадки в часі t в перезволожених глинистих грунтах, на прикладі суглинку видно, що криві, отримані шляхом експеременту відрізняються від класичної теорії Терцагі-Герсеванова в кількісному відношенні.Considered rheological changes waterlogged clay soils with compression and compression compared with the classical theories of filtration consolidation Terzaghi-Gersevanov. Found that the coefficients of relative compression mvi factors at different time ti increase significantly. mvi coefficient greater increase occurs during the completion of filtration consolidation tf. When comparing the change in pore pressure uw and precipitation over time t in waterlogged clay soils, loam example shows that the curves obtained an experimental way, different from the classical theory of Terzaghi-Gersevanov quantitatively.Рассмотрены реологические изменения переувлажненных глинистых грунтов при компрессионном сжатии и сопоставлены с классическими теориями фильтрационной консолидации Терцаги-Герсеванова. Установлено, что коэффициенты относительного сжатия mvi при разных факторах времени ti существенно увеличиваются. Увеличение коэффициента mvi возникает во время завершения консолидационной фильтрации tf. При сопоставлении изменения поровых давлений uw и осадки во времени t в переувлажненных глинистых грунтах, на примере суглинка видно, что кривые, полученные эксперементальным путем, отличаются от классической теории Терцаги-Герсеванова в количественном отношении

    On the n=4 Supersymmetry for the FRW Model

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    In this work we have constructed the n=4 extended local conformal time supersymmetry for the Friedmann-Robertson-Walker (FRW) cosmological models. This is based on the superfield construction of the action, which is invariant under wordline local n=4 supersymmetry with SU(2)localSU(2)globalSU(2)_{local} \otimes SU(2)_{global} internal symmetry. It is shown that the supersymmetric action has the form of the localized (or superconformal) version of the action for n=4 supersymmetric quantum mechanics. This superfield procedure provides a well defined scheme for including supermatter.Comment: 8 pages. Accepted for publication in Phys. Rev

    Potent E. coli M‑17 Growth Inhibition by Ultrasonically Complexed Acetylsalicylic Acid−ZnO−Graphene Oxide Nanoparticles

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    A single-step ultrasonic method (20 kHz) is demonstrated for the complexation of acetylsalicylic acid (ASA)−ZnO− graphene oxide (GO) nanoparticles with an average size of <70 nm in aqueous solution. ASA−ZnO−GO more e ffi ciently inhibits the growth of probiotic Escherichia coli strain M-17 and exhibits enhanced antioxidant properties than free ASA and ASA−ZnO in neutralization of hydroxyl radicals in the electro-Fenton process. This improved function of ASA in the ASA −ZnO GO can be attributed to the well-de fi ned cone-shaped morphology, the surface structure containing hydroxyl and carboxylate groups of ZnO−GO nanoparticles, which facilitated the complexation with ASA

    Electron and hole states in quantum-dot quantum wells within a spherical 8-band model

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    In order to study heterostructures composed both of materials with strongly different parameters and of materials with narrow band gaps, we have developed an approach, which combines the spherical 8-band effective-mass Hamiltonian and the Burt's envelope function representation. Using this method, electron and hole states are calculated in CdS/HgS/CdS/H_2O and CdTe/HgTe/CdTe/H_2O quantum-dot quantum-well heterostructures. Radial components of the wave functions of the lowest S and P electron and hole states in typical quantum-dot quantum wells (QDQWs) are presented as a function of radius. The 6-band-hole components of the radial wave functions of an electron in the 8-band model have amplitudes comparable with the amplitude of the corresponding 2-band-electron component. This is a consequence of the coupling between the conduction and valence bands, which gives a strong nonparabolicity of the conduction band. At the same time, the 2-band-electron component of the radial wave functions of a hole in the 8-band model is small compared with the amplitudes of the corresponding 6-band-hole components. It is shown that in the CdS/HgS/CdS/H_2O QDQW holes in the lowest states are strongly localized in the well region (HgS). On the contrary, electrons in this QDQW and both electron and holes in the CdTe/HgTe/CdTe/H_2O QDQW are distributed through the entire dot. The importance of the developed theory for QDQWs is proven by the fact that in contrast to our rigorous 8-band model, there appear spurious states within the commonly used symmetrized 8-band model.Comment: 15 pages, 5 figures, E-mail addresses: [email protected], [email protected]
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