435 research outputs found

    Maximally Symmetric Minimal Unification Model SO(32) with Three Families in Ten Dimensional Space-time

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    Based on a maximally symmetric minimal unification hypothesis and a quantum charge-dimension correspondence principle, it is demonstrated that each family of quarks and leptons belongs to the Majorana-Weyl spinor representation of 14-dimensions that relate to quantum spin-isospin-color charges. Families of quarks and leptons attribute to a spinor structure of extra 6-dimensions that relate to quantum family charges. Of particular, it is shown that 10-dimensions relating to quantum spin-family charges form a motional 10-dimensional quantum space-time with a generalized Lorentz symmetry SO(1,9), and 10-dimensions relating to quantum isospin-color charges become a motionless 10-dimensional quantum intrinsic space. Its corresponding 32-component fermions in the spinor representation possess a maximal gauge symmetry SO(32). As a consequence, a maximally symmetric minimal unification model SO(32) containing three families in ten dimensional quantum space-time is naturally obtained by choosing a suitable Majorana-Weyl spinor structure into which quarks and leptons are directly embedded. Both resulting symmetry and dimensions coincide with the ones of type I string and heterotic string SO(32) in string theory.Comment: 17 pages, RevTex, published version with minor typos correcte

    Electrical characteristics of layered palladium alkanethiolates by conducting atomic force microscopy

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    Current-voltage measurements on individual Pd(II) alkanethiolate nanostructures of varying bilayer thicknesses (hexyl to hexadecyl) employing conducting atomic force microscopy have shown the presence of a low current region near zero bias, the width of which increases with the bilayer thickness. The resistance in this region varies exponentially with the bilayer thickness with a low decay parameter value of 0.2±0.04 Å-1 indicating a long-range nonresonant tunneling through the alkyl chains. The changeover from low current to high current with increasing bias is accompanied by a negative differential resistance feature, which arises due to Pd-S charge transfer

    Factors Associated with Diarrhea in Noebeba, Middle South Timor, East Nusa Tenggara

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    Background: Acute diarrheal diseases remain a leading cause of global morbidity and mortality particularly among young children in resource-limited countries. Large studies are also currently underway evaluating novel and potential easy-to-implement water sanitation and hygiene (WASH) preventive strategies. This study aimed to examine factors associated with diarrhea in Noebeba, South Timor Tengah. Subjects and Method: This was a cross-sectional study conducted in Noebeba, Middle South Timor, East Nusa Tenggara. A sample of 355 mothers was selected for this study by simple random sampling. The dependent variable was diarrhea. The independent variables were household water container ownership, latrine ownership, maternal knowledge, handwashing practice, trash bin, and food sanitation. The data were collected by questionnaire. The data were analyzed by a multiple logistic regression. Results: Household water container ownership (OR= 0.21; p= 0.003), latrine ownership (OR= 0.32; p< 0.001), good maternal knowledge (OR= 0.62; p<0.001), and handwashing practice (OR= 0.41; p< 0.001) were associated with a decreased incidence of diarrhea. Trash bin and food sanitation did not show statistical significance with incidence of diarrhea. Conclusion: Household water container ownership, latrine ownership, good maternal knowledge, and handwashing practice, are associated with a decreased incidence of diarrhea. Keywords: diarrhea, hygiene, sanitation, risk factor

    Non SUSY Unification in Left-Right Models

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    We explore in a model independent way the possibility of achieving the non supersymmetric gauge coupling unification within left-right symmetric models, with the minimal particle content at the left-right mass scale which could be as low as 1 TeV in a variety of models, and with a unification scale M in the range 10510^5 GeV <M<1017.7< M< 10^{17.7} GeV.Comment: 18 pages, Latex file, uses epsf style, four figures. Submitted for publication to Phys. Rev. D on Oct. 13, 199

    Entanglement Efficiencies in PT-Symmetric Quantum Mechanics

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    The degree of entanglement is determined for an arbitrary state of a broad class of PT-symmetric bipartite composite systems. Subsequently we quantify the rate with which entangled states are generated and show that this rate can be characterized by a small set of parameters. These relations allow one in principle to improve the ability of these systems to entangle states. It is also noticed that many relations resemble corresponding ones in conventional quantum mechanics.Comment: Published version with improved figures, 5 pages, 2 figure

    See-Saw Masses for Quarks and Leptons in SU(5)

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    We build on a recent paper by Grinstein, Redi and Villadoro, where a see-saw like mechanism for quark masses was derived in the context of spontaneously broken gauged flavour symmetries. The see-saw mechanism is induced by heavy Dirac fermions which are added to the Standard Model spectrum in order to render the flavour symmetries anomaly-free. In this letter we report on the embedding of these fermions into multiplets of an SU(5) grand unified theory and discuss a number of interesting consequences.Comment: 15 pages, 4 figures (v3: outline restructured, modified mechanism to cancel anomalies

    Thermodynamics of the (1,1/2) Ferrimagnet in Finite Magnetic Fields

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    We investigate the specific heat and magnetisation of a ferrimagnet with gS=1 and S=1/2 spins in a finite magnetic field using the transfer matrix DMRG down to T=0.025J. Ferromagnetic gapless and antiferromagnetic gapped excitations for H=0 lead to rich thermodynamics for H > 0. While the specific heat is characterized by a generic double peak structure, magnetisation reveals two critical fields, Hc1=1.76(1) and Hc2=3.00(1) with square-root behaviour in the T=0 magnetisation. Simple analytical arguments allow to understand these experimentally accessible findings.Comment: 5 pages, 7 eps figures, uses RevTeX, submitted to PR

    Charge density analysis of two proton transfer complexes: understanding hydrogen bonding and determination of in-crystal dipole moments

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    An experimental charge density study has been carried out on proton-transfer complexes exhibiting nonlinear optical (NLO) properties-melaminium tartrate monohydrate and L-asparaginium picrate employing high-resolution X-ray diffraction at 100 K. Both the complexes crystallize in non-centric space group P21 and the structures exhibit interesting patterns of N-H...O and O-H...O hydrogen bonding. Experimental determination of the dipole moment (μ) for the asymmetric unit reveals that for both the crystals, there is a large cooperative enhancement in the crystalline μ arising essentially due to hydrogen bond mediated charge transfer between the melaminium ion and the L-tartrate in one case, between the Lasparaginium ion and the picrate in the other complex. We have additionally performed theoretical calculations at the density functional theory (DFT) level to understand the origin of enhancement of the dipole moments in the two systems

    Elementary excitations in one-dimensional spin-orbital models: neutral and charged solitons and their bound states

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    We study, both numerically and variationally, the interplay between different types of elementary excitations in the model of a spin chain with anisotropic spin-orbit coupling, in the vicinity of the "dimer line" with an exactly known dimerized ground state. Our variational treatment is found to be in a qualitative agreement with the exact diagonalization results. Soliton pairs are shown to be the lowest excitations only in a very narrow region of the phase diagram near the dimer line, and the phase transitions are always governed by magnon-type excitations which can be viewed as soliton-antisoliton bound states. It is shown that when the anisotropy exceeds certain critical value, a new phase boundary appears. In the doped model on the dimer line, the exact elementary charge excitation is shown to be a hole bound to a soliton. Bound states of those "charged solitons" are studied; exact solutions for N-hole bound states are presented.Comment: 11 pages revtex, 6 figure

    Sign Rules for Anisotropic Quantum Spin Systems

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    We present new and exact ``sign rules'' for various spin-s anisotropic spin-lattice models. It is shown that, after a simple transformation which utilizes these sign rules, the ground-state wave function of the transformed Hamiltonian is positive-definite. Using these results exact statements for various expectation values of off-diagonal operators are presented, and transitions in the behavior of these expectation values are observed at particular values of the anisotropy. Furthermore, the effects of sign rules in variational calculations and quantum Monte Carlo calculations are considered. They are illustrated by a simple variational treatment of a one-dimensional anisotropic spin model.Comment: 4 pages, 1 ps-figur
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