3,171 research outputs found

    Different Traces of Quantum Systems Having the Same Classical Limit

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    Many quantum systems may have the same classical limit. We argue that in the classical limit their traces do not necessarily converge one to another. The trace formula allows to express quantum traces by means of classical quantities as sums over periodic orbits of the classical system. To explain the lack of convergence of the traces we need the quantum corrections to the classical actions of periodic orbits. The four versions of the quantum baker map on the sphere serve as an illustration of this problem.Comment: LaTeX 4 pages, 2 figures included, final published versio

    Wage Regimes, Accumulation and Finance Constraints: Keynesian Unemployment Revisited

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    This paper presents a sequential model suited to analyze transitions between equilibria. Disequilibrium dynamics are obtained from a standard monopolistic competition model, by introducing a sequential structure and reasonable hypotheses about technology, finance constraints, expectation formation, and the wage setting mechanism. The response to shocks crucially depends on the institutional features of the economy, and on the monetary policy stance. In particular, some degree of wage stickiness proves necessary to avoid explosive paths. This feature of the model makes it a good candidate for the reappraisal of Keynes’ arguments on wages and unemployment.Disequilibrium, Keynesian Economics, Fix Price Models, Time to Build

    Periodic orbit quantization of chaotic maps by harmonic inversion

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    A method for the semiclassical quantization of chaotic maps is proposed, which is based on harmonic inversion. The power of the technique is demonstrated for the baker's map as a prototype example of a chaotic map.Comment: 7 pages, 1 figure, accepted for publication in Phys. Lett.

    Is psychiatry becoming more coercive?

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    The rising trend is damaging for patients, unsupported by evidence, and must be reversed

    Contact between adult children and their divorced parents: Italy in a comparative perspective

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    This paper, based on a Multipurpose survey on a large national sample of Italian households which has made possible to analyse parent-child and grandparent-child dyads, explores the impact of marital instability on relationships with adult children and with grandchildren. As in other countries, the impact is more negative in the case of divorce than in case of widowhood and, in both cases, more negative for men than for women. It affects the threegenerational relationship and is not compensated by stronger horizontal kinship ties. The impact is most negative in the case of contacts, while in the case of material support it is more neutral and even positive for widowed parents, confirming the strong role played by need in Mediterranean countries in the case of the latter. Not only divorce/separation, also remarriage has a negative impact on intergenerational contacts. And in this case the impact is stronger for women than for men. An exploratory comparison with countries where divorce rates are higher and have a different gender culture suggests that although the impact of marital instability is negative in both cases, its intensity is higher in Italy. These results offer new insight into the working of strong family ties. These ties, particularly in the case of men, are more vulnerable to the dissolution of marital bonds than in countries with weak family ties. Finally, family ties are strongly mediated and constructed by women and through relationships between women. When a mother is no longer present alongside the father, even in the case of widowhood, fathers and grandfathers risk weakening the intergenerational link. --
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