Slow quench dynamics of a trapped one-dimensional Bose gas confined to an optical lattice

We analyze the effect of a linear time-variation of the interaction strength on a trapped one-dimensional Bose gas confined to an optical lattice. The evolution of different observables such as the experimentally accessible onsite particle distribution are studied as a function of the ramp time using time-dependent exact diagonalization and density-matrix renormalization group techniques. We find that the dynamics of a trapped system typically display two regimes: for long ramp times, the dynamics are governed by density redistribution, while at short ramp times, local dynamics dominate as the evolution is identical to that of an homogeneous system. In the homogeneous limit, we also discuss the non-trivial scaling of the energy absorbed with the ramp time.Comment: 4 pages, 4 figures, version published in PR

L’extension juridique des conventions collectives au Québec : une approche comparative

Après avoir rappelé les nombreuses études que le gouvernement du Québec a fait réaliser depuis une vingtaine d'années sur les régimes européens d'extension juridique des conventions collectives, l'auteur recourt à l'approche comparative pour tenter de dégager un certain nombre de questions susceptibles défavoriser un réexamen du système québécois d'extension juridique.Since 1964, the Government of Québec has sent no less than five fact-finding missions to Europe to study collective agreements by industrial sector. Of particular interest to the Government has been the question of judicial extension of collective agreements. This interest in comparative studies is understandable, in view of the fact that Québec was the only government in North America to adopt a system of judicial extension of collective agreements (inspired largely by ideas in circulation overseas). None of these missions, nevertheless has resulted in significant changes to the legislation of the 1930's.Judicial extension is situated in very different contexts on the European continent and in Québec. In the former, it is part of a long tradition of collective negotiations by industrial sector; in the latter, collective negotiations are undertaken by individual firms. Moreover, in Europe, extension operates in concert with the general system of collective agreements, whereas in Québec there is a total separation between the general system (as defined in theLabour Code) and that pertaining to extension (as defined in the 1934 legislation). In addition, whereas Europe extended agreements are complete in themselves, Québec law only makes provision for the extension of certain articles: those dealing with wages hours, job classification, paid holidays, and a few social benefits.In view of the potential impact of extended collective agreements, in the economic as well as the social sphere, judicial extension is not automatic anywhere, but it is subject to procedures involving public information and consultation.Québec's Minister of Labour has considerable discretionary powers which allow him to make changes in the contents of a collective agreement before extending it. This may be seen as a complement to the idea of regulation.The study of foreign Systems of enlarged negotiation, accompanied or not by a mecanism of judicial extension, suggest questions pertinent to a re-examination of our own system of negotiation and extension.1) As a society, do we prefer the conventional or regulatory approach to determining working conditions? This is a fondamental point. The frequent intervention of the Québec Government gives the impression that it favours an increasingly legislative and regulatory approach.2) Adopting a system of extended collective bargaining in a context based on the tradition of decentralized negotiations represents a considerable challenge. This is particularly the case regarding the exercise of freedom of association and of union activities.3) Is it possible to imagine a system of extended negotiation which allows for union pluralism and leads to agreements which the Government could make compulsory for management and labour in a given sector?4) What is the meaning of the Minister of Labour's discretionary power in reorganizing and clarifying articles in collective agreements before extending them? Does the Minister intend to promote collective negotiations by respecting the contractual power of the parties involved or does he favour continuing the use of his legal powers to further the process of government regulation?5) As far as control and inspection of extended collective agreements is concerned, Québec has innovated. It has given the parties themselves, through use of the 'joint committee', the control of applying decrees, whereas in other countries this role is assumed by government labour inspection services. These committees have become the scène of negotiations for the renewal of collective agreements lending themselves to extension generally in an atmosphere of management-labour cooperation. It may be asked whether this is the best body to determine working conditions and see to their application?In reply to these questions, it would be advisable first to avoid any attempt at premature importing of formulas created elsewhere, and second, to accept only those which are related to our practice and which enjoy sufficient support among the interested parties