4,527 research outputs found

    The Schr\"odinger-Langevin equation with and without thermal fluctuations

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    The Schr\"odinger-Langevin (SL) equation is considered as an effective open quantum system formalism suitable for phenomenological applications involving a quantum subsystem interacting with a thermal bath. We focus on two open issues relative to its solutions: the stationarity of the excited states of the non-interacting subsystem when one considers the dissipation only and the thermal relaxation toward asymptotic distributions with the additional stochastic term. We first show that a proper application of the Madelung/polar transformation of the wave function leads to a non zero damping of the excited states of the quantum subsystem. We then study analytically and numerically the SL equation ability to bring a quantum subsystem to the thermal equilibrium of statistical mechanics. To do so, concepts about statistical mixed states and quantum noises are discussed and a detailed analysis is carried with two kinds of noise and potential. We show that within our assumptions the use of the SL equation as an effective open quantum system formalism is possible and discuss some of its limitations.Comment: 38 pages, 31 figure

    Semi-classical approach to J/ψJ/\psi suppression in high energy heavy-ion collisions

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    We study the heavy quark/antiquark pair dynamics in strongly-coupled quark gluon plasma. A semi-classical approach, based on the Wigner distribution and Langevin dynamics, is applied to a color screened ccˉc{\bar c} pair, in a hydrodynamically cooling fireball, to evaluate the total J/ψJ/\psi suppression at both RHIC and LHC energies. Although its limitation is observed, this approach results to a J/ψJ/\psi suppression of around 0.30 at RHIC and 0.25 at LHC.Comment: 4 pages, 6 figures, Proceeding for International Conference on Strangeness in Quark Matter 2013 (SQM 2013) at Birmingha

    Impact of Regulatory Agencies on the Efficiency of Publicly-Owned Utilities

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    We compare the economic efficiency of a publicly-owned utility directly controlled by the government with a publicly-owned utility regulated by a public utility commission (PUC). Regulation by a PUC is modelled as a Nash equilibrium of a game between two principals, the government and the PUC, each of them having control over a subset of decision variables determining the utility performance. A utility manager, who has private information over a productivity parameter, is the agent. Comparisons of both regulatory regimes are made with respect to output, choice of inputs, manager's information rent and firm's profit. Reasons for which the government should prefer one regulatory regime over the other are discussed. The recent regulatory reform of electricity markets in the province of Quebec (Canada) provides an illustration of the model.Regulation, Public Enterprises

    International Competition between Public or Mixed Enterprises

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    We develop a model in which two firms from different countries compete on each other domestic market. Each firm is jointly owned by the residents and the government of its country. The extent of the government's stake in the public enterprise is endogenous and it determines the weight given to domestic consumers' surplus in the firm's payoff function. We show that the choice of each government's stake depends on a trade-off between allocative efficiency on the domestic market and profitability of foreign markets. We also highlight the fact that the government's stake in one country has an impact on firms' behavior in both countries.Regulation, public enterprises, duopoly

    International Competition Between Public or Mixed Enterprises

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    We develop a model in which two firms from different countries compete on each other domestic market. Each firms is jointly owned by the residents and the government of its country. The extent of the government's stake in the public enterprise is endogenous and it determines the weight given the domestic consumers' surplus inithe firm's payoff function. We show that the choice of each government's stake depends on a trade-off between allocative efficiency on the domestic market and profitability of foreign markets. We also highlight the fact that the government's stake in on country has an impact of firms' behavior in both countries.Regulation, Public Enterprises, Duopoly

    The present status of the teacher-training curriculum for men in health and physical education in Negro institutions of higher learning

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    Thesis (Ed.M.)--Boston University, 1948. This item was digitized by the Internet Archive

    Public Relations in the Small High School

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