26,809 research outputs found

    Ergodic and localized regions in quantum spin glasses on the Bethe lattice

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    By considering the quantum dynamics of a transverse field Ising spin glass on the Bethe lattice we find the existence of a many body localized region at small transverse field and low temperature. The region is located within the thermodynamic spin glass phase. Accordingly, we conjecture that quantum dynamics inside the glassy region is split in a small MBL and a large delocalized (but not necessarily ergodic) region. This has implications for the analysis of the performance of quantum adiabatic algorithms.Comment: 19 pages, 6 figures. Invited paper for the issue on Breakdown of ergodicity in quantum systems: from solids to synthetic matter of Philosophical Transactions A of the Royal Societ

    Graph ambiguity

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    In this paper, we propose a rigorous way to define the concept of ambiguity in the domain of graphs. In past studies, the classical definition of ambiguity has been derived starting from fuzzy set and fuzzy information theories. Our aim is to show that also in the domain of the graphs it is possible to derive a formulation able to capture the same semantic and mathematical concept. To strengthen the theoretical results, we discuss the application of the graph ambiguity concept to the graph classification setting, conceiving a new kind of inexact graph matching procedure. The results prove that the graph ambiguity concept is a characterizing and discriminative property of graphs. (C) 2013 Elsevier B.V. All rights reserved

    Prediction of the relationship between body weight and body condition score in sheep

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    During the whole production cycle it is important to monitor the energy balance and to quantify body reserve changes of the ewes. This can be done, both in experimental settings and in the field, by estimating the body condition score (BCS) of the ewes and its variations. However, if this tool is used to balance the diets it is necessary to know the relationship between BCS and body weight (BW), which varies depending on the mature size of the breed and of the population considered within each breed. The relationship between BW and BCS has been studied only for some sheep breeds and populations. For this reason, this research aimed to develop a prediction model of this relationship in ewes for any breed or population
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