4,383 research outputs found

    On non-Markovian time evolution in open quantum systems

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    Non-Markovian reduced dynamics of an open system is investigated. In the case the initial state of the reservoir is the vacuum state, an approximation is introduced which makes possible to construct a reduced dynamics which is completely positive

    Entropy production and detailed balance for a class of quantum Markov semigroups

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    We give an explicit entropy production formula for a class of quantum Markov semigroups, arising in the weak coupling limit of a system coupled with reservoirs, whose generators L\mathcal{L} are sums of other generators Lω\mathcal{L}_\omega associated with positive Bohr frequencies ω\omega of the system. As a consequence, we show that any such semigroup satisfies the quantum detailed balance condition with respect to an invariant state if and only if all semigroups generated by each Lω\mathcal{L}_\omega so do with respect to the same invariant state

    Chilean Exile: Trauma and Opportunities

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    The article explores the experience of the Chilean school for refugee children created in South Yorkshire in the 70’s / 80’s. It provides an account of the first Chilean school for exiled children created in England. The article considers the circumstances that both the children, and their parents faced, separately and as a family unit in their new lives as refugees. This was a key impetus to set up a resource within the community. How the school was organised, and the collectively agreed objectives are described

    Rational points on X_0^+ (p^r)

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    We show how the recent isogeny bounds due to \'E. Gaudron and G. R\'emond allow to obtain the triviality of X_0^+ (p^r)(Q), for r>1 and p a prime exceeding 2.10^{11}. This includes the case of the curves X_split (p). We then prove, with the help of computer calculations, that the same holds true for p in the range 10 < p < 10^{14}, p\neq 13. The combination of those results completes the qualitative study of such sets of rational points undertook in previous papers, with the exception of p=13.Comment: 16 pages, no figur

    Gribov gap equation at finite temperature

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    In this paper the Gribov gap equation at finite temperature is analyzed. The solutions of the gap equation (which depend explicitly on the temperature) determine the structure of the gluon propagator within the semi-classical Gribov approach. The present analysis is consistent with the standard confinement scenario for low temperatures, while for high enough temperatures, deconfinement takes place and a free gluon propagator is obtained. It also suggests the presence of the so-called semi-quark-gluon-plasma phase in between the confined and quark-gluon plasma phases.Comment: 22 pages, 9 figures. Comments added, relevant references include

    Be bold and take a challenge: could motivational strategies improve help-seeking?

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    Part of the motivation behind the evolution of learning environments is the idea of providing students with individualized instructional strategies that allow them to learn as much as possible. It has been suggested that the goals an individual holds create a framework or orientation from which they react and respond to events. There is a large evidence-based literature which supports the notion of mastery and performance approaches to learning and which identifies distinct behavioural patterns associated with each. However, it remains unclear how these orientations manifest themselves within the individual: an important question to address when applying goal theory to the development of a goal-sensitive learner model. This paper exposes some of these issues by describing two empirical studies. They approach the subject from different perspectives, one from the implementation of an affective computing system and the other a classroom-based study, have both encountered the same empirical and theoretical problems: the dispositional/situational aspect and the dimensionality of goal orientation
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