3,544 research outputs found

    Coherent evolution via reservoir driven holonomy

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    We show that in the limit of strongly interacting environment a system initially prepared in a Decoherence Free Subspace (DFS) coherently evolves in time, adiabatically following the changes of the DFS. If the reservoir cyclicly evolves in time, the DFS states acquire an holonomy.Comment: 4 page

    Hydrogen-enhanced local plasticity in aluminum: an ab initio study

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    Dislocation core properties of Al with and without H impurities are studied using the Peierls-Nabarro model with parameters determined by ab initio calculations. We find that H not only facilitates dislocation emission from the crack tip but also enhances dislocation mobility dramatically, leading to macroscopically softening and thinning of the material ahead of the crack tip. We observe strong binding between H and dislocation cores, with the binding energy depending on dislocation character. This dependence can directly affect the mechanical properties of Al by inhibiting dislocation cross-slip and developing slip planarity.Comment: 4 pages, 3 figure

    On multigraded generalizations of Kirillov-Reshetikhin modules

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    We study the category of Z^l-graded modules with finite-dimensional graded pieces for certain Z+^l-graded Lie algebras. We also consider certain Serre subcategories with finitely many isomorphism classes of simple objects. We construct projective resolutions for the simple modules in these categories and compute the Ext groups between simple modules. We show that the projective covers of the simple modules in these Serre subcategories can be regarded as multigraded generalizations of Kirillov-Reshetikhin modules and give a recursive formula for computing their graded characters

    The production rate of the coarse grained Gibbs entropy and the Kolmogorov-Sinai entropy: a real connection ?

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    We discuss the connection between the Kolmogorov-Sinai entropy, hKSh_{KS}, and the production rate of the coarse grained Gibbs entropy, rGr_G. Detailed numerical computations show that the (often accepted) identification of the two quantities does not hold in systems with intermittent behavior and/or very different characteristic times and in systems presenting pseudo-chaos. The basic reason of this fact is in the asymptotic (with respect to time) nature of hKSh_{KS}, while rGr_G is a quantity related to short time features of a system.Comment: 8 pages, 5 figures Submitted to PR
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