420 research outputs found

    High order Fuchsian equations for the square lattice Ising model: χ(6)\chi^{(6)}

    Full text link
    This paper deals with χ~(6)\tilde{\chi}^{(6)}, the six-particle contribution to the magnetic susceptibility of the square lattice Ising model. We have generated, modulo a prime, series coefficients for χ~(6)\tilde{\chi}^{(6)}. The length of the series is sufficient to produce the corresponding Fuchsian linear differential equation (modulo a prime). We obtain the Fuchsian linear differential equation that annihilates the "depleted" series Φ(6)=χ~(6)23χ~(4)+245χ~(2)\Phi^{(6)}=\tilde{\chi}^{(6)} - {2 \over 3} \tilde{\chi}^{(4)} + {2 \over 45} \tilde{\chi}^{(2)}. The factorization of the corresponding differential operator is performed using a method of factorization modulo a prime introduced in a previous paper. The "depleted" differential operator is shown to have a structure similar to the corresponding operator for χ~(5)\tilde{\chi}^{(5)}. It splits into factors of smaller orders, with the left-most factor of order six being equivalent to the symmetric fifth power of the linear differential operator corresponding to the elliptic integral EE. The right-most factor has a direct sum structure, and using series calculated modulo several primes, all the factors in the direct sum have been reconstructed in exact arithmetics.Comment: 23 page

    The Ising model and Special Geometries

    Full text link
    We show that the globally nilpotent G-operators corresponding to the factors of the linear differential operators annihilating the multifold integrals χ(n)\chi^{(n)} of the magnetic susceptibility of the Ising model (n6n \le 6) are homomorphic to their adjoint. This property of being self-adjoint up to operator homomorphisms, is equivalent to the fact that their symmetric square, or their exterior square, have rational solutions. The differential Galois groups are in the special orthogonal, or symplectic, groups. This self-adjoint (up to operator equivalence) property means that the factor operators we already know to be Derived from Geometry, are special globally nilpotent operators: they correspond to "Special Geometries". Beyond the small order factor operators (occurring in the linear differential operators associated with χ(5) \chi^{(5)} and χ(6) \chi^{(6)}), and, in particular, those associated with modular forms, we focus on the quite large order-twelve and order-23 operators. We show that the order-twelve operator has an exterior square which annihilates a rational solution. Then, its differential Galois group is in the symplectic group Sp(12,C) Sp(12, \mathbb{C}). The order-23 operator is shown to factorize in an order-two operator and an order-21 operator. The symmetric square of this order-21 operator has a rational solution. Its differential Galois group is, thus, in the orthogonal group SO(21,C) SO(21, \mathbb{C}).Comment: 33 page

    Renormalization, isogenies and rational symmetries of differential equations

    Full text link
    We give an example of infinite order rational transformation that leaves a linear differential equation covariant. This example can be seen as a non-trivial but still simple illustration of an exact representation of the renormalization group.Comment: 36 page

    Globally nilpotent differential operators and the square Ising model

    Full text link
    We recall various multiple integrals related to the isotropic square Ising model, and corresponding, respectively, to the n-particle contributions of the magnetic susceptibility, to the (lattice) form factors, to the two-point correlation functions and to their lambda-extensions. These integrals are holonomic and even G-functions: they satisfy Fuchsian linear differential equations with polynomial coefficients and have some arithmetic properties. We recall the explicit forms, found in previous work, of these Fuchsian equations. These differential operators are very selected Fuchsian linear differential operators, and their remarkable properties have a deep geometrical origin: they are all globally nilpotent, or, sometimes, even have zero p-curvature. Focusing on the factorised parts of all these operators, we find out that the global nilpotence of the factors corresponds to a set of selected structures of algebraic geometry: elliptic curves, modular curves, and even a remarkable weight-1 modular form emerging in the three-particle contribution χ(3) \chi^{(3)} of the magnetic susceptibility of the square Ising model. In the case where we do not have G-functions, but Hamburger functions (one irregular singularity at 0 or \infty) that correspond to the confluence of singularities in the scaling limit, the p-curvature is also found to verify new structures associated with simple deformations of the nilpotent property.Comment: 55 page

    Unrolled primal-dual networks for lensless cameras

    Get PDF
    Conventional models for lensless imaging assume that each measurement results from convolving a given scene with a single experimentally measured point-spread function. These models fail to simulate lensless cameras truthfully, as these models do not account for optical aberrations or scenes with depth variations. Our work shows that learning a supervised primal-dual reconstruction method results in image quality matching state of the art in the literature without demanding a large network capacity. We show that embedding learnable forward and adjoint models improves the reconstruction quality of lensless images (+5dB PSNR) compared to works that assume a fixed point-spread function

    Difference system for Selberg correlation integrals

    Full text link
    The Selberg correlation integrals are averages of the products s=1ml=1n(xszl)μs\prod_{s=1}^m\prod_{l=1}^n (x_s - z_l)^{\mu_s} with respect to the Selberg density. Our interest is in the case m=1m=1, μ1=μ\mu_1 = \mu, when this corresponds to the μ\mu-th moment of the corresponding characteristic polynomial. We give the explicit form of a (n+1)×(n+1)(n+1) \times (n+1) matrix linear difference system in the variable μ\mu which determines the average, and we give the Gauss decomposition of the corresponding (n+1)×(n+1)(n+1) \times (n+1) matrix. For μ\mu a positive integer the difference system can be used to efficiently compute the power series defined by this average.Comment: 21 page

    Mining remittances corresponding to metalliferous ores: regulation and budget impact

    Get PDF
    Economic statistics and forecasting show that Romania has a very favourable potential as far as the metalliferous ores are concerned. As these are owned by the state, once they are allowed to be exploited, they generate considerable amounts for the consolidated public budget. The present paper is meant to conduct a synthetic analysis on the topic of mining remittances from an economic perspective, by considering the juridical framework of capitalizing deposits of ferrous and non-ferrous ores, correlated with the general regulations concerning property and the specific existing regulations of the EU and of the countries that have experience and potential in the mining sector

    Mining remittances corresponding to metalliferous ores: regulation and budget impact

    Get PDF
    Economic statistics and forecasting show that Romania has a very favourable potential as far as the metalliferous ores are concerned. As these are owned by the state, once they are allowed to be exploited, they generate considerable amounts for the consolidated public budget. The present paper is meant to conduct a synthetic analysis on the topic of mining remittances from an economic perspective, by considering the juridical framework of capitalizing deposits of ferrous and non-ferrous ores, correlated with the general regulations concerning property and the specific existing regulations of the EU and of the countries that have experience and potential in the mining sector

    NuMI Beam Monitoring Simulation and Data Analysis Status and Progress

    Get PDF
    With the Main Injector Neutrino Oscillation Search (MINOS) experiment decommissioned, muon and hadron monitors became an important diagnostic tool for the NuMI Off-axis v Appearance (NOvA) experiment at Fermilab to monitor the Neutrinos at the Main Injector (NuMI) beam. The goal of this study is to maintain the quality of the monitor signals and to establish correlations with the neutrino beam profile. And we carry out a systematic study of the response of the muon monitors to the changes in the parameters of the proton beam and lattice parameters. We report here on the progress of the beam data analysis and comparison with the simulation results
    corecore