227 research outputs found

    Effect of strain-induced electronic topological transitions on the superconducting properties of LaSrCuO thin films

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    We propose a Ginzburg-Landau phenomenological model for the dependence of the critical temperature on microscopic strain in tetragonal high-Tc cuprates. Such a model is in agreement with the experimental results for LSCO under epitaxial strain, as well as with the hydrostatic pressure dependence of Tc in most cuprates. In particular, a nonmonotonic dependence of Tc on hydrostatic pressure, as well as on in-plane or apical microstrain, is derived. From a microscopic point of view, such results can be understood as due to the proximity to an electronic topological transition (ETT). In the case of LSCO, we argue that such an ETT can be driven by a strain-induced modification of the band structure, at constant hole content, at variance with a doping-induced ETT, as is usually assumed.Comment: EPJB, to be publishe

    Constant Angle Surfaces in \H^2\times \R

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    In this paper we classify constant angle surfaces in \H^2\times\R, where \H^2 is the hyperbolic plane.Comment: 9 Latex page

    Optical Flow on Evolving Surfaces with an Application to the Analysis of 4D Microscopy Data

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    We extend the concept of optical flow to a dynamic non-Euclidean setting. Optical flow is traditionally computed from a sequence of flat images. It is the purpose of this paper to introduce variational motion estimation for images that are defined on an evolving surface. Volumetric microscopy images depicting a live zebrafish embryo serve as both biological motivation and test data.Comment: The final publication is available at link.springer.co

    On certain surfaces in the Euclidean space E3{\mathbb{E}}^3

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    In the present paper we classify all surfaces in \E^3 with a canonical principal direction. Examples of these type of surfaces are constructed. We prove that the only minimal surface with a canonical principal direction in the Euclidean space E3{\mathbb{E}}^3 is the catenoid.Comment: 13 Latex page

    The structure of uniform discrete defective crystals

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    In the continuum context, a uniform crystal has dislocation density tensor constant in space. A simple iteration procedure generates an infinite set of points which is associated with uniform defective crystals. When certain necessary conditions are satisfied, there is a minimum (non-zero) separation of points in this set, so the set is discrete. We describe the structure of such sets explicitly, and show in particular that any such set is either a simple lattice or a 4-lattice

    Constant-angle surfaces in liquid crystals

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    We discuss some properties of surfaces in R3 whose unit normal has constant angle with an assigned direction field. The constant angle condition can be rewritten as an Hamilton-Jacobi equation correlating the surface and the direction field. We focus on examples motivated by the physics of interfaces in liquid crystals and of layered fluids, and discuss the properties of the constant-angle surfaces when the direction field is singular along a line (disclination) or at a point (hedgehog defect

    A coarse-grained model of the expansionof the human rhinovirus 2 capsid revealsinsights in genome release

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    Human rhinoviruses are causative agents of the common cold. In order torelease their RNA genome into the host during a viral infection, these smallviruses must undergo conformational changes in their capsids, whosedetailed mechanism is strictly related to the process of RNA extrusion,which has been only partially elucidated. We study here a mathematicalmodel for the structural transition between the native particle of human rhi-novirus type 2 and its expanded form, viewing the process as an energycascade, i.e. a sequence of metastable states with decreasing energy connectedby minimum energy paths. We explore several transition pathways anddiscuss their implications for the RNA exit proces
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