412 research outputs found
Supersymmetric FRW model and the ground state of supergravity
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 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 .
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
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
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
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
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
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 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
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
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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