1,869 research outputs found

    Public Goals, Property Values, and Regional Cooperation

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    Do public officials care about property values? If so, are their decisions about tax rates, public spending, land use, and regional cooperation paying off? Fiscal and land use data for Connecticut’s 169 towns offer some insights about development patterns and how local public policies may affect the value of real property—structures and land. We look at the effects of municipal tax, spending and land-use policies, as well as the impact of regional cooperation—in the form of regional school districts—on the value of real property per acre of available land. Fiscal policies and the level of development have the anticipated effects on property values, but the impact of participation in regional high school districts is less clear.

    Comment on "Towards a large deviation theory for strongly correlated systems"

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    I comment on a recent paper by Ruiz and Tsallis [Phys. Lett. A 376, 2451 (2012)] claiming to have found a 'qq-exponential' generalization of the large deviation principle for strongly correlated random variables. I show that the basic scaling results that they find numerically can be reproduced with a simple example involving independent random variables, and are not specifically related to the qq-exponential function. In fact, identical scaling results can be obtained with any other power-law deformations of the exponential. Thus their results do not conclusively support their claim of a qq-exponential generalization of the large deviation principle.Comment: Comment, 3 pages, 2 figure

    Bouchaud-M\'ezard model on a random network

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    We studied the Bouchaud-M\'ezard(BM) model, which was introduced to explain Pareto's law in a real economy, on a random network. Using "adiabatic and independent" assumptions, we analytically obtained the stationary probability distribution function of wealth. The results shows that wealth-condensation, indicated by the divergence of the variance of wealth, occurs at a larger JJ than that obtained by the mean-field theory, where JJ represents the strength of interaction between agents. We compared our results with numerical simulation results and found that they were in good agreement.Comment: to be published in Physical Review

    On the Extreme Flights of One-Sided Levy Processes

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    We explore the statistical behavior of the order statistics of the flights of One-sided Levy Processes (OLPs). We begin with the study of the extreme flights of general OLPs,and then focus on the class of selfsimilar processes,investigating the following issues:(i)the inner hierarchy of the extreme flights - for example:how big is the 7th largest flight relative to the 2nd largest one?; and,(ii)the relative contribution of the extreme flights to the entire 'flight aggregate' - for example: how big is the 3rd largest flight relative to the OLP's value?. Furthermore, we show that all 'hierarchical' results obtained - but not the 'aggregate' results - are explicitly extendable to the class of OLPs with arbitrary power-law flight tails (which is far larger than the selfsimilar class).Comment: 21 pages. This manuscript is an extended version of a contribution to a special Physica A volume in honor of Shlomo Havlin on his sixtieth birthda

    Simple observations concerning black holes and probability

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    It is argued that black holes and the limit distributions of probability theory share several properties when their entropy and information content are compared. In particular the no-hair theorem, the entropy maximization and holographic bound, and the quantization of entropy of black holes have their respective analogues for stable limit distributions. This observation suggests that the central limit theorem can play a fundamental role in black hole statistical mechanics and in a possibly emergent nature of gravity.Comment: 6 pages Latex, final version. Essay awarded "Honorable Mention" in the Gravity Research Foundation 2009 Essay Competitio

    A sharp uniform bound for the distribution of sums of Bernoulli trials

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    In this note we establish a uniform bound for the distribution of a sum Sn=X1++XnS_n=X_1+\cdots+X_n of independent non-homogeneous Bernoulli trials. Specifically, we prove that σnP(Sn ⁣= ⁣j)η\sigma_n \mathbb{P}(S_n\!=\!j)\leq\eta where σn\sigma_n denotes the standard deviation of SnS_n and η\eta is a universal constant. We compute the best possible constant η0.4688\eta\sim 0.4688 and we show that the bound also holds for limits of sums and differences of Bernoullis, including the Poisson laws which constitute the worst case and attain the bound. We also investigate the optimal bounds for nn and jj fixed. An application to estimate the rate of convergence of Mann's fixed point iterations is presented.Comment: This paper is a revised version of a previous articl

    High-energy gluon bremsstrahlung in a finite medium: harmonic oscillator versus single scattering approximation

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    A particle produced in a hard collision can lose energy through bremsstrahlung. It has long been of interest to calculate the effect on bremsstrahlung if the particle is produced inside a finite-size QCD medium such as a quark-gluon plasma. For the case of very high-energy particles traveling through the background of a weakly-coupled quark-gluon plasma, it is known how to reduce this problem to an equivalent problem in non-relativistic two-dimensional quantum mechanics. Analytic solutions, however, have always resorted to further approximations. One is a harmonic oscillator approximation to the corresponding quantum mechanics problem, which is appropriate for sufficiently thick media. Another is to formally treat the particle as having only a single significant scattering from the plasma (known as the N=1 term of the opacity expansion), which is appropriate for sufficiently thin media. In a broad range of intermediate cases, these two very different approximations give surprisingly similar but slightly differing results if one works to leading logarithmic order in the particle energy, and there has been confusion about the range of validity of each approximation. In this paper, I sort out in detail the parametric range of validity of these two approximations at leading logarithmic order. For simplicity, I study the problem for small alpha_s and large logarithms but alpha_s log << 1.Comment: 40 pages, 23 figures [Primary change since v1: addition of new appendix reviewing transverse momentum distribution from multiple scattering

    Analysis of generalized negative binomial distributions attached to hyperbolic Landau levels

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    To each hyperbolic Landau level of the Poincar\'e disc is attached a generalized negative binomial distribution. In this paper, we compute the moment generating function of this distribution and supply its decomposition as a perturbation of the negative binomial distribution by a finitely-supported measure. Using the Mandel parameter, we also discuss the nonclassical nature of the associated coherent states. Next, we determine the L\'evy-Kintchine decomposition its characteristic function when the latter does not vanish and deduce that it is quasi-infinitely divisible except for the lowest hyperbolic Landau level corresponding to the negative binomial distribution. By considering the total variation of the obtained quasi-L\'evy measure, we introduce a new infinitely-divisible distribution for which we derive the characteristic function

    Alternative sampling for variational quantum Monte Carlo

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    Expectation values of physical quantities may accurately be obtained by the evaluation of integrals within Many-Body Quantum mechanics, and these multi-dimensional integrals may be estimated using Monte Carlo methods. In a previous publication it has been shown that for the simplest, most commonly applied strategy in continuum Quantum Monte Carlo, the random error in the resulting estimates is not well controlled. At best the Central Limit theorem is valid in its weakest form, and at worst it is invalid and replaced by an alternative Generalised Central Limit theorem and non-Normal random error. In both cases the random error is not controlled. Here we consider a new `residual sampling strategy' that reintroduces the Central Limit Theorem in its strongest form, and provides full control of the random error in estimates. Estimates of the total energy and the variance of the local energy within Variational Monte Carlo are considered in detail, and the approach presented may be generalised to expectation values of other operators, and to other variants of the Quantum Monte Carlo method.Comment: 14 pages, 9 figure
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