Importance Sampling for Dispersion-managed Solitons

The dispersion-managed nonlinear Schrödinger (DMNLS) equation governs the long-term dynamics of systems which are subject to large and rapid dispersion variations. We present a method to study large, noise-induced amplitude and phase perturbations of dispersion-managed solitons. The method is based on the use of importance sampling to bias Monte Carlo simulations toward regions of state space where rare events of interest—large phase or amplitude variations—are most likely to occur. Implementing the method thus involves solving two separate problems: finding the most likely noise realizations that produce a small change in the soliton parameters, and finding the most likely way that these small changes should be distributed in order to create a large, sought-after amplitude or phase change. Both steps are formulated and solved in terms of a variational problem. In addition, the first step makes use of the results of perturbation theory for dispersion-managed systems recently developed by the authors. We demonstrate this method by reconstructing the probability density function of amplitude and phase deviations of noise-perturbed dispersion-managed solitons and comparing the results to those of the original, unaveraged system

Importance Sampling for Dispersion-managed Solitons

The dispersion-managed nonlinear Schrödinger (DMNLS) equation governs the long-term dynamics of systems which are subject to large and rapid dispersion variations. We present a method to study large, noise-induced amplitude and phase perturbations of dispersion-managed solitons. The method is based on the use of importance sampling to bias Monte Carlo simulations toward regions of state space where rare events of interest—large phase or amplitude variations—are most likely to occur. Implementing the method thus involves solving two separate problems: finding the most likely noise realizations that produce a small change in the soliton parameters, and finding the most likely way that these small changes should be distributed in order to create a large, sought-after amplitude or phase change. Both steps are formulated and solved in terms of a variational problem. In addition, the first step makes use of the results of perturbation theory for dispersion-managed systems recently developed by the authors. We demonstrate this method by reconstructing the probability density function of amplitude and phase deviations of noise-perturbed dispersion-managed solitons and comparing the results to those of the original, unaveraged system

The Organizational Implications of Creativity: The US Film Industry in Mid-XXth Century

We develop a basic framework to understand the organization of highly creative activities. Management faces a fundamental tradeoff in organizing such activities. On the one hand, since creativity cannot be achieved by command and control or by monetary incentives, internal/contractual production of creative products is plagued by hazards arising from their fundamental characteristics: extremely high input, output and market uncertainty, and the inherent informational advantages of creative talent. Procuring highly creative products in the market place, though, exposes the distributor to a fundamental risk: independently produced creative goods are generic distribution-wise. Thus, in procuring creative products in the marketplace, distributors face the unavoidable winner's curse risk. Since this risk is, to a large extent, independent of the creative nature of the product, the higher the creative content, the higher the relative hazards associated with internal or contractual production. Thus, internal/contractual production of creative goods will tend to be less prevalent the higher the creative content associated with its production. We apply this insight to the evolution of the U.S. film industry in the mid-XXth century. We exploit two simultaneous natural experiments -- the diffusion of TV and the Paramount antitrust decision forcing the separation of exhibitors from distributors and prohibiting the use of block-booking. Both events increased the demand for creative content in movies. We develop empirical implications which we test by analyzing in detail the decision by distributors to produce films internally or to procure then in the market place, in the face of an increase in the demand for creative content.

Buy, Lobby or Sue: Interest Groups' Participation in Policy Making - A Selective Survey

The participation of interest groups in public policy making is unavoidable. Its unavoidable nature is only matched by the universal suspicion with which it has been seen by both policy makers and the public. Recently, however, there has been a growing literature that examines the participation of interest groups in public policy making from a New Institutional Economics perspective. The distinguishing feature of the New Institutional Economics Approach is its emphasis in opening up the black box of decision-making, whether in understanding the rules of the game, or the play of the game. In this paper we do not attempt to fairly describe the vast literature on interest group's behavior. Instead, the purpose of this essay for the New Institutional Economics Guide Book is to review recent papers that follow the NIE mantra. That is, they attempt to explicate the micro-analytic features of the way interest groups actually interact with policy-makers, rather than providing an abstract high-level representation. We emphasize the role of the institutional environment in understanding interest groups' strategies.

Low error measurement-free phase gates for qubus computation

We discuss the desired criteria for a two-qubit phase gate and present a method for realising such a gate for quantum computation that is measurement-free and low error. The gate is implemented between qubits via an intermediate bus mode. We take a coherent state as the bus and use cross-Kerr type interactions between the bus and the qubits. This new method is robust against parameter variations and is thus low error. It fundamentally improves on previous methods due its deterministic nature and the lack of approximations used in the geometry of the phase rotations. This interaction is applicable both to solid state and photonic qubit systems.Comment: 6 pages, 4 figures. Published versio

Strategic Judicial Decision Making

This survey paper starts from the basic, and intuitive, assumption that judges are human and as such, can be modeled in the same fashion we model politicians, activists, managers: driven by well-defined preferences, behaving in a purposive and forward-looking fashion. We explore, then, the role politics play in judicial decision-making. We provide a brief overview of what is called the "strategic approach," compare it to alternative approaches to understand judicial behavior, and offer some concluding thoughts about the future of positive analyses of judicial decision-making.

Judicial lobbying: The politics of labor law constitutional interpretation

This paper links the theory of interest groups influence over the legislature with that of congressional control over the judiciary. The resulting framework reconciles the theoretical literature of lobbying with the negative available evidence on the impact of lobbying over legislative outcomes, and sheds light to the determinants of lobbying in separation-of-powers systems. We provide conditions for judicial decisions to be sensitive to legislative lobbying, and find that lobbying falls the more divided the legislature is on the relevant issues. We apply this framework to analyze supreme court labor decisions in Argentina, and find results consistent with the predictions of the theory

Competition and mergers in airline networks / 1523

Includes bibliographical references (p. 25)

Damage Valuation of Indirect Expropriation in Public Services

damage valuation, expropriation, public services, contracting, privatization