62 research outputs found

    Mesoscopic Phase Fluctuations: General Phenomenon in Condensed Matter

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    General conditions for the occurrence of mesoscopic phase fluctuations in condensed matter are considered. The description of different thermodynamic phases, which coexist as a mixture of mesoscopically separated regions, is based on the {\it theory of heterophase fluctuations}. The spaces of states, typical of the related phases, are characterized by {\it weighted Hilbert spaces}. Several models illustrate the main features of heterophase condensed matter.Comment: 23 pages, Latex, no figure

    Mesoscopic Phase Separation in Anisotropic Superconductors

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    General properties of anisotropic superconductors with mesoscopic phase separation are analysed. The main conclusions are as follows: Mesoscopic phase separation can be thermodynamically stable only in the presence of repulsive Coulomb interactions. Phase separation enables the appearance of superconductivity in a heterophase sample even if it were impossible in pure-phase matter. Phase separation is crucial for the occurrence of superconductivity in bad conductors. Critical temperature for a mixture of pairing symmetries is higher than the critical temperature related to any pure gap-wave symmetry of this mixture. In bad conductors, the critical temperature as a function of the superconductivity fraction has a bell shape. Phase separation makes the single-particle energy dispersion softer. For planar structures phase separation suppresses d-wave superconductivity and enhances s-wave superconductivity. These features are in agreement with experiments for cuprates.Comment: Revtex file, 25 pages, 2 figure

    An asymptotic treatment of the Elenbaas–Heller equation for a radiating wall‐stabilized high‐pressure gas‐discharge arc

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    An asymptotic analysis of the Elenbaas–Heller equation for a radiating wall-stabilized high-pressure gas-discharge arc is given. This analysis applies when the operating temperatures within the arc are lower than the ionization temperature by an order of magnitude. It is shown that for arcs that are radiating highly efficiently a further asymptotic treatment can be given. It is shown under what conditions, governed by a dimensionless parameter M, this limiting case prevails. Comparison with earlier results put forward by Zollweg [J. Appl. Phys. 49, 1077 (1978)] shows satisfactory agreement

    Basics of Bose-Einstein Condensation

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    The review is devoted to the elucidation of the basic problems arising in the theoretical investigation of systems with Bose-Einstein condensate. Understanding these challenging problems is necessary for the correct description of Bose-condensed systems. The principal problems considered in the review are as follows: (i) What is the relation between Bose-Einstein condensation and global gauge symmetry breaking? (ii) How to resolve the Hohenberg-Martin dilemma of conserving versus gapless theories? (iii) How to describe Bose-condensed systems in strong spatially random potentials? (iv) Whether thermodynamically anomalous fluctuations in Bose systems are admissible? (v) How to create nonground-state condensates? Detailed answers to these questions are given in the review. As examples of nonequilibrium condensates, three cases are described: coherent modes, turbulent superfluids, and heterophase fluids.Comment: Review articl

    Heavy and light roles: myosin in the morphogenesis of the heart

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    Myosin is an essential component of cardiac muscle, from the onset of cardiogenesis through to the adult heart. Although traditionally known for its role in energy transduction and force development, recent studies suggest that both myosin heavy-chain and myosin lightchain proteins are required for a correctly formed heart. Myosins are structural proteins that are not only expressed from early stages of heart development, but when mutated in humans they may give rise to congenital heart defects. This review will discuss the roles of myosin, specifically with regards to the developing heart. The expression of each myosin protein will be described, and the effects that altering expression has on the heart in embryogenesis in different animal models will be discussed. The human molecular genetics of the myosins will also be reviewed
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