The Effectiveness of State and Local Regulation of Handguns: A Statistical Analysis

One aspect of the continuing debate over weapons control, apart from Constitutional issues, is whether legislation is inherently capable of reducing crime and deaths by shooting. The opponents of increased control, tacitly admitting that empirical evidence is one means for measuring the effect of weapons regulation, have contended that [e]xpert opinion and compelling evidence seem to indicate that the amount or kind of crime in a community is not substantially affected by the relative ease with which a person can obtain a firearm. National Rifle Association of America, The Gun Law Problem 10. In the following study the authors employ data analysis techniques to examine the efficacy of state and municipal controls on handguns. They conclude that many lives would be saved if all states increased their level of control to that of New Jersey, the state having the most stringent gun control laws

The Effectiveness of State and Local Regulation of Handguns: A Statistical Analysis

One aspect of the continuing debate over weapons control, apart from Constitutional issues, is whether legislation is inherently capable of reducing crime and deaths by shooting. The opponents of increased control, tacitly admitting that empirical evidence is one means for measuring the effect of weapons regulation, have contended that [e]xpert opinion and compelling evidence seem to indicate that the amount or kind of crime in a community is not substantially affected by the relative ease with which a person can obtain a firearm. National Rifle Association of America, The Gun Law Problem 10. In the following study the authors employ data analysis techniques to examine the efficacy of state and municipal controls on handguns. They conclude that many lives would be saved if all states increased their level of control to that of New Jersey, the state having the most stringent gun control laws

Complexity in parametric Bose-Hubbard Hamiltonians and structural analysis of eigenstates

We consider a family of chaotic Bose-Hubbard Hamiltonians (BHH) parameterized by the coupling strength $k$ between neighboring sites. As $k$ increases the eigenstates undergo changes, reflected in the structure of the Local Density of States. We analyze these changes, both numerically and analytically, using perturbative and semiclassical methods. Although our focus is on the quantum trimer, the presented methodology is applicable for the analysis of longer lattices as well.Comment: 4 pages, 4 figure

Metal-insulator transitions in cyclotron resonance of periodic nanostructures due to avoided band crossings

A recently found metal-insulator transition in a model for cyclotron resonance in a two-dimensional periodic potential is investigated by means of spectral properties of the time evolution operator. The previously found dynamical signatures of the transition are explained in terms of avoided band crossings due to the change of the external electric field. The occurrence of a cross-like transport is predicted and numerically confirmed

Quenched and Negative Hall Effect in Periodic Media: Application to Antidot Superlattices

We find the counterintuitive result that electrons move in OPPOSITE direction to the free electron E x B - drift when subject to a two-dimensional periodic potential. We show that this phenomenon arises from chaotic channeling trajectories and by a subtle mechanism leads to a NEGATIVE value of the Hall resistivity for small magnetic fields. The effect is present also in experimentally recorded Hall curves in antidot arrays on semiconductor heterojunctions but so far has remained unexplained.Comment: 10 pages, 4 figs on request, RevTeX3.0, Europhysics Letters, in pres

Anomalous diffusion as a signature of collapsing phase in two dimensional self-gravitating systems

A two dimensional self-gravitating Hamiltonian model made by $N$ fully-coupled classical particles exhibits a transition from a collapsing phase (CP) at low energy to a homogeneous phase (HP) at high energy. From a dynamical point of view, the two phases are characterized by two distinct single-particle motions : namely, superdiffusive in the CP and ballistic in the HP. Anomalous diffusion is observed up to a time $\tau$ that increases linearly with $N$. Therefore, the finite particle number acts like a white noise source for the system, inhibiting anomalous transport at longer times.Comment: 10 pages, Revtex - 3 Figs - Submitted to Physical Review

Fractal Conductance Fluctuations of Classical Origin

In mesoscopic systems conductance fluctuations are a sensitive probe of electron dynamics and chaotic phenomena. We show that the conductance of a purely classical chaotic system with either fully chaotic or mixed phase space generically exhibits fractal conductance fluctuations unrelated to quantum interference. This might explain the unexpected dependence of the fractal dimension of the conductance curves on the (quantum) phase breaking length observed in experiments on semiconductor quantum dots.Comment: 5 pages, 4 figures, to appear in PR

Sequential Desynchronization in Networks of Spiking Neurons with Partial Reset

The response of a neuron to synaptic input strongly depends on whether or not it has just emitted a spike. We propose a neuron model that after spike emission exhibits a partial response to residual input charges and study its collective network dynamics analytically. We uncover a novel desynchronization mechanism that causes a sequential desynchronization transition: In globally coupled neurons an increase in the strength of the partial response induces a sequence of bifurcations from states with large clusters of synchronously firing neurons, through states with smaller clusters to completely asynchronous spiking. We briefly discuss key consequences of this mechanism for more general networks of biophysical neurons