591 research outputs found

    Social Reformers and Regulation: The Prohibition of Cigarettes in the U.S. and Canada

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    The apogee of anti-smoking legislation in North America was reached early in the last century. In 1903, the Canadian Parliament passed a resolution prohibiting the manufacture, importation, and sale of cigarettes. Around the same time, fifteen states in the United States banned the sale of cigarettes and thirty-five states considered prohibitory legislation. In both the United States and Canada, prohibition was part of a broad political, economic, and social coalition termed the Progressive Movement. Cigarette prohibition was special interest regulation, though not of the usual narrow neoclassical genre; it was the means by which a group of crusaders sought to alter the behavior of a much larger segment of the population. The opponents of cigarette regulation were cigarette smokers and the more organized cigarette lobby. An active Progressive Movement was the necessary condition for generating interest in prohibition, while the anti-prohibition forces played a more significant role later in the legislative process. The moral reformers' succeeded when they faced little opposition because few constituents smoked and/or no jobs were at stake because there was no cigarette industry. In other words, reform is easy when you are preaching to the converted.

    Who Should Govern Congress? Access to Power and the Salary Grab of 1873

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    We examine the politics of the %u201CSalary Grab%u201D of 1873, legislation that increased congressional salaries retroactively by 50 percent. A group of New England and Midwestern elites opposed the Salary Grab, along with congressional franking and patronage-based civil service appointments, as part of reform effort to reshape %u201Cwho should govern Congress.%u201D Our analyses of congressional voting confirm the existence of this non-party elite coalition. While these elites lost many legislative battles in the short-run, their efforts kept reform on the legislative agenda throughout the late-nineteenth century and ultimately set the stage for the Progressive movement in the early-twentieth century.

    Weyl law for fat fractals

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    It has been conjectured that for a class of piecewise linear maps the closure of the set of images of the discontinuity has the structure of a fat fractal, that is, a fractal with positive measure. An example of such maps is the sawtooth map in the elliptic regime. In this work we analyze this problem quantum mechanically in the semiclassical regime. We find that the fraction of states localized on the unstable set satisfies a modified fractal Weyl law, where the exponent is given by the exterior dimension of the fat fractal.Comment: 8 pages, 4 figures, IOP forma

    On the resonance eigenstates of an open quantum baker map

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    We study the resonance eigenstates of a particular quantization of the open baker map. For any admissible value of Planck's constant, the corresponding quantum map is a subunitary matrix, and the nonzero component of its spectrum is contained inside an annulus in the complex plane, ∣zminâˆŁâ‰€âˆŁzâˆŁâ‰€âˆŁzmax∣|z_{min}|\leq |z|\leq |z_{max}|. We consider semiclassical sequences of eigenstates, such that the moduli of their eigenvalues converge to a fixed radius rr. We prove that, if the moduli converge to r=∣zmax∣r=|z_{max}|, then the sequence of eigenstates converges to a fixed phase space measure ρmax\rho_{max}. The same holds for sequences with eigenvalue moduli converging to ∣zmin∣|z_{min}|, with a different limit measure ρmin\rho_{min}. Both these limiting measures are supported on fractal sets, which are trapped sets of the classical dynamics. For a general radius ∣zmin∣<r<∣zmax∣|z_{min}|< r < |z_{max}|, we identify families of eigenstates with precise self-similar properties.Comment: 32 pages, 2 figure

    Some open questions in "wave chaos"

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    The subject area referred to as "wave chaos", "quantum chaos" or "quantum chaology" has been investigated mostly by the theoretical physics community in the last 30 years. The questions it raises have more recently also attracted the attention of mathematicians and mathematical physicists, due to connections with number theory, graph theory, Riemannian, hyperbolic or complex geometry, classical dynamical systems, probability etc. After giving a rough account on "what is quantum chaos?", I intend to list some pending questions, some of them having been raised a long time ago, some others more recent

    Using the Hadamard and related transforms for simplifying the spectrum of the quantum baker's map

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    We rationalize the somewhat surprising efficacy of the Hadamard transform in simplifying the eigenstates of the quantum baker's map, a paradigmatic model of quantum chaos. This allows us to construct closely related, but new, transforms that do significantly better, thus nearly solving for many states of the quantum baker's map. These new transforms, which combine the standard Fourier and Hadamard transforms in an interesting manner, are constructed from eigenvectors of the shift permutation operator that are also simultaneous eigenvectors of bit-flip (parity) and possess bit-reversal (time-reversal) symmetry.Comment: Version to appear in J. Phys. A. Added discussions; modified title; corrected minor error

    Coarse Grained Liouville Dynamics of piecewise linear discontinuous maps

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    We compute the spectrum of the classical and quantum mechanical coarse-grained propagators for a piecewise linear discontinuous map. We analyze the quantum - classical correspondence and the evolution of the spectrum with increasing resolution. Our results are compared to the ones obtained for a mixed system.Comment: 11 pages, 8 figure

    Training deep neural density estimators to identify mechanistic models of neural dynamics

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    Mechanistic modeling in neuroscience aims to explain observed phenomena in terms of underlying causes. However, determining which model parameters agree with complex and stochastic neural data presents a significant challenge. We address this challenge with a machine learning tool which uses deep neural density estimators-- trained using model simulations-- to carry out Bayesian inference and retrieve the full space of parameters compatible with raw data or selected data features. Our method is scalable in parameters and data features, and can rapidly analyze new data after initial training. We demonstrate the power and flexibility of our approach on receptive fields, ion channels, and Hodgkin-Huxley models. We also characterize the space of circuit configurations giving rise to rhythmic activity in the crustacean stomatogastric ganglion, and use these results to derive hypotheses for underlying compensation mechanisms. Our approach will help close the gap between data-driven and theory-driven models of neural dynamics

    Fractal Weyl law for chaotic microcavities: Fresnel's laws imply multifractal scattering

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    We demonstrate that the harmonic inversion technique is a powerful tool to analyze the spectral properties of optical microcavities. As an interesting example we study the statistical properties of complex frequencies of the fully chaotic microstadium. We show that the conjectured fractal Weyl law for open chaotic systems [W. T. Lu, S. Sridhar, and M. Zworski, Phys. Rev. Lett. 91, 154101 (2003)] is valid for dielectric microcavities only if the concept of the chaotic repeller is extended to a multifractal by incorporating Fresnel's laws.Comment: 8 pages, 12 figure
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