179 research outputs found

    Neural-network quantum state study of the long-range antiferromagnetic Ising chain

    Full text link
    We investigate quantum phase transitions in the transverse field Ising chain with algebraically decaying long-range antiferromagnetic interactions by using the variational Monte Carlo method with the restricted Boltzmann machine being employed as a trial wave function ansatz. In the finite-size scaling analysis with the order parameter and the second R\'enyi entropy, we find that the central charge deviates from 1/2 at a small decay exponent αLR\alpha_\mathrm{LR} in contrast to the critical exponents staying very close to the short-range (SR) Ising values regardless of αLR\alpha_\mathrm{LR} examined, supporting the previously proposed scenario of conformal invariance breakdown. To identify the threshold of the Ising universality and the conformal symmetry, we perform two additional tests for the universal Binder ratio and the conformal field theory (CFT) description of the correlation function. It turns out that both indicate a noticeable deviation from the SR Ising class at αLR<2\alpha_\mathrm{LR} < 2. However, a closer look at the scaled correlation function for αLR2\alpha_\mathrm{LR} \ge 2 shows a gradual change from the asymptotic line of the CFT verified at αLR=3\alpha_\mathrm{LR} = 3, providing a rough estimate of the threshold being in the range of 2αLR<32 \lesssim \alpha_\mathrm{LR} < 3

    Race, inequality, and social capital in the U.S. counties

    Get PDF
    This study examines how the interplay between racial diversity and economic inequality affects variations of social capital in the U.S. counties. In general, racial and economic heterogeneity is assumed to provide a negative environment for the growth of social capital. Building on this, we argue the effect of economic inequality is weaker than that of racial diversity because increased economic heterogeneity is felt less visibly and acutely than racial heterogeneity. Moreover, economic inequality can positively condition the adverse impact of racial diversity on social capital when the two interact. Based on the crosscutting cleavages theory, income inequality in a racially fragmented community works as an additional cleavage that crosscuts the different racial groups, mitigating the negative impact of racial diversity on social capital. The data analysis of 3,140 U.S. counties in 2009-2014 provides strong evidence for our arguments. Our findings offer important implications in understanding inequality, race and American democracy

    Income Inequality, Social Mobility, and Electoral Participation in the U.S. Counties: Revisiting the Inequality-Participation Nexus

    Get PDF
    Previous research has provided contested hypotheses about the impact of income inequality on electoral participation. This study reexamines the debate between conflict and relative power theories by focusing on a largely ignored factor: social mobility. We argue that social mobility conditions the inequality-participation nexus by alleviating the frustration, class conflict, and efficacy gaps between the rich and the poor that the prevailing theories assume income inequality to create. By utilizing the Cooperative Congressional Election Survey, we test this argument focusing on US counties. Our analysis confirms that the effects of income inequality on citizens’ likelihood of voting vary depending on mobility, suggesting that social mobility provides a crucial context in which income inequality can play out in substantially different ways. This article implies that more scholarly endeavors should be made to clarify the multifaceted structure of inequality for improving our understanding of the relationship between economic and political inequality

    Nonlinear Fokker-Planck collision operator in Rosenbluth form for gyrokinetic simulations using discontinuous Galerkin method

    Get PDF
    Department of Nuclear EngineeringA gyroaveraged nonlinear collision operator is formulated based on the Fokker-Planck operator in the Rosenbluth-MacDonald-Judd (RMJ) potential form and implemented for the gyrokinetic simulations with the discontinuous Galerkin scheme. The divergence structure of the original RMJ form is carefully preserved throughout the formulation to guarantee the density conservation while neglecting the finite Larmor radius effect. The B-spline finite element method is used to calculate the Rosenbluth potentials for the nonlinear collision operator. In addition to the nonlinear collision operator, linear and Dougherty collision models are also implemented to assess the benefits and drawbacks of each model. For the conservation of the parallel momentum and energy, we adopt a simple advection-diffusion model which numerically enforces the conservation of physical quantities. From bump-on-tail relaxation tests, the monotonically increasing entropy in time and conservation properties are demonstrated for the developed collision operator. Also, a few theoretical predictions for the neoclassical physics such as the neoclassical heat flux, poloidal flow and collisional damping of zonal flow are successfully reproduced by numerical simulations.ope

    Data on race, inequality, and social capital in the U.S. counties

    Get PDF
    This article presents data on social capital at the United States’ county-level. Following Rupasingha et al. (2006), the social capital index captures the common factor among density measures of 10 different types of associations, voter turnout rates, U.S. decennial census participation rates, and the number of non-profit organizations. Based on Knack (2003), we create associational densities measures as a proxy for both bridging and bonding social capital. Including data on income inequality, racial diversity, minority group size, average household income, educational attainment, the ratio of a family household, the size of migration population, and female labor market participation rates, the data covers 3,104 U.S. counties for both 2009 and 2014. This paper includes descriptive statistics and figures. This data article is associated with the article “Race, Inequality, and Social Capital in the U.S. Counties.

    Economic Inequality and Political Participation in East Asian Democracies: The Role of Perceived Income Inequality and Intergenerational Mobility

    Get PDF
    This study examines how perceptions of economic inequality affect political participation focusing on East Asian democracies. It develops nuanced predictions on how perceptions of income inequality and social mobility and their interplay affect individuals’ engagement in various types of political activities in six East Asian democracies. Using the fourth wave of the Asian Barometer Survey, we examine novel arguments built upon the existing inequality-participation nexus. Our analysis suggests that inequality is a multifaceted concept, and the mechanisms of the inequality-participation nexus could vary depending on the regional, socioeconomic, and political context

    Neoliberal reform and protest in Latin American democracies: A replication and correction

    Get PDF
    Do neoliberal economic reforms in Latin American democracies mobilize citizens to overcome their collective action problems and protest? A recent addition to the scholarship on this crucial question of the relationship of markets and politics, Bellinger and Arce (2011), concludes that economic liberalization does have this effect, working to repoliticize collective actors and reinvigorate democracy. We reexamine the article’s analyses and demonstrate that they misinterpret the marginal effect of the variables of theoretical interest. Thus, the article’s optimistic claims about the consequences for democracy of economic liberalization in the region are not supported by its own empirical results. It is argued here that its results suggest instead that protests became more common in autocracies when they moved away from markets. Rather than speaking to how people have mobilized to protest against liberal reforms in Latin America’s democracies, the work’s analyses illuminate only when people protested against the region’s dictatorship
    corecore