1,153 research outputs found

    Effective action of a five-dimensional domain wall

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    We calculate the four-dimensional low-energy effective action for the perturbations of a two-scalar domain wall model in five dimensions. Comparison of the effective action to the Nambu-Goto action reveals the presence of an additional coupling between the light scalar field and the massless translation mode (branon excitation), which can be written in terms of the curvature scalar of the induced metric. We comment on the impact of this interaction to branon physics.Comment: 24 page

    Multi-instantons in seven dimensions

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    We consider the self-dual Yang-Mills equations in seven dimensions. Modifying the t'Hooft construction of instantons in d=4d=4, we find NN-instanton 7d7d solutions which depend on 8N8N effective parameters and are E6E_{6}-invariant.Comment: 9 pages, LaTeX, no figure

    Zero-brane approach to quantization of biscalar field theory about topological kink-bell solution

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    We study the properties of the topologically nontrivial doublet solution arisen in the biscalar theory with a fourth-power potential introducing an example of the spontaneous breaking of symmetry. We rule out the zero-brane (non-minimal point particle) action for this doublet as a particle with curvature. When quantizing it as the theory with higher derivatives, we calculate the quantum corrections to the mass of the doublet which could not be obtained by means of the perturbation theory.Comment: some references were adde

    Existence and Stability of Non-Trivial Scalar Field Configurations in Orbifolded Extra Dimensions

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    We consider the existence and stability of static configurations of a scalar field in a five dimensional spacetime in which the extra spatial dimension is compactified on an S1/Z2S^1/Z_2 orbifold. For a wide class of potentials with multiple minima there exist a finite number of such configurations, with total number depending on the size of the orbifold interval. However, a Sturm-Liouville stability analysis demonstrates that all such configurations with nodes in the interval are unstable. Nodeless static solutions, of which there may be more than one for a given potential, are far more interesting, and we present and prove a powerful general criterion that allows a simple determination of which of these nodeless solutions are stable. We demonstrate our general results by specializing to a number of specific examples, one of which may be analyzed entirely analytically.Comment: 23 pages, 7 figures, references added, factor of two corrected in kink energy definition, submitted to PR

    The Association and Dissociation Tendencies of the Coaxial and Non- Coaxial Components of Shear Strength of Soils to Environment

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    Soil is rock on its way to ocean. It undergoes many changes during the travel. The important factors which influence the geo-technical behavior of soil are : Grain size and Shape, Gradation, Water, Parent rock materials and Environment. The Geo-technical behavior of fine grains in soil is highly complex than coarse grains. A pure cohesive soil has pure shear or coaxial shear component only. A pure friction soil has Non-coaxial or simple shear component only. Normally a soil sample is a mixture of coarse and fine grains. The shear strength is shared between coaxial and non-coaxial component of the total shear strength of soil. The environment influences the Geo-technical behavior of soil. The coaxial and non-coaxial components of shear strength (coax and non-coax) of soil accepts and adjusts to reach a new equilibrium in stability. In this paper the association and dissociation of coax and non-coax with environmental conditions starting from laboratory and ending in marine environment through examples, illustrations and documented, reliable data available in literature

    Aharonov-Bohm effect in higher genus materials

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    Flux periodicity of conducting electrons on a closed surface with genus two g=2g=2 (double torus) are investigated theoretically. We examine flux periodicity of the ground-state energy and of the wave functions as a function of applied magnetic field. A fundamental flux period of the ground-state energy is twice a fundamental unit of magnetic flux for uniformly applied magnetic field, which is shown to be valid for a simple ladder geometry and carbon double torus. Flux periodicity of the wave functions in a double torus is complicate as compared with a simple torus (g=1g=1), and an adiabatic addition of magnetic fluxes does not provide a good quantum number for the energy eigenstates. The results are extended to higher genus materials and the implications of the results are discussed.Comment: 4 pages, 6 figure

    Non-topological gravitating defects in five-dimensional anti-de Sitter space

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    A class of five-dimensional warped solutions is presented. The geometry is everywhere regular and tends to five-dimensional anti-de Sitter space for large absolute values of the bulk coordinate. The physical features of the solutions change depending on the value of an integer parameter. In particular, a set of solutions describes generalized gravitating kinks where the scalar field interpolates between two different minima of the potential. The other category of solutions describes instead gravitating defects where the scalar profile is always finite and reaches the same constant asymptote both for positive and negative values of the bulk coordinate. In this sense the profiles are non-topological. The physical features of the zero modes are discussed.Comment: 9 pages, 4 figure

    Soliton Trap in Strained Graphene Nanoribbons

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    The wavefunction of a massless fermion consists of two chiralities, left-handed and right-handed, which are eigenstates of the chiral operator. The theory of weak interactions of elementally particle physics is not symmetric about the two chiralities, and such a symmetry breaking theory is referred to as a chiral gauge theory. The chiral gauge theory can be applied to the massless Dirac particles of graphene. In this paper we show within the framework of the chiral gauge theory for graphene that a topological soliton exists near the boundary of a graphene nanoribbon in the presence of a strain. This soliton is a zero-energy state connecting two chiralities and is an elementally excitation transporting a pseudospin. The soliton should be observable by means of a scanning tunneling microscopy experiment.Comment: 7 pages, 4 figure

    Interaction of human recombinant αA- and αB-crystallins with early and late unfolding intermediates of citrate synthase on its thermal denaturation

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    AbstractWe have investigated the role of recombinant human αA- and αB-crystallins in the heat-induced inactivation and aggregation of citrate synthase. Homo-multimers of both αA- and αB-crystallins confer protection against heat-induced inactivation in a concentration-dependent manner and also prevent aggregation. Interaction of crystallins with early unfolding intermediates of citrate synthase reduces their partitioning into aggregation-prone intermediates. This appears to result in enhanced population of early unfolding intermediates that can be reactivated by its substrate, oxaloacetate. Both these homo-multimers do not form a stable complex with the early unfolding intermediates. However, they can form a soluble, stable complex with aggregation-prone late unfolding intermediates. This soluble complex formation prevents aggregation. Thus, it appears that the chaperone activity of α-crystallin involves both transient and stable interactions depending on the nature of intermediates on the unfolding pathway; one leads to reactivation of the enzyme activity while the other prevents aggregation

    Routing in Extremely Mobile Networks

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    We consider the problem of routing in a highly mobile network which is never fully connected. We describe algorithms that allow to route a packet toward a remote destinations. The packet bounces from connected components to connected components, thanks to node mobility
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