SearcharxivSearch

arXiv · hep-lat/9404002

Critical Point Correlation Function for the 2D Random Bond Ising Model

Abstract

High accuracy Monte Carlo simulation results for 1024*1024 Ising system with ferromagnetic impurity bonds are presented. Spin-spin correlation function at a critical point is found to be numerically very close to that of a pure system. This is not trivial since a critical temperature for the system with impurities is almost two times lower than pure Ising $T_c$. Finite corrections to the correlation function due to combined action of impurities and finite lattice size are described.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Andrei L. Talapov, Lev N. Shchur. 1994-04-05. Critical Point Correlation Function for the 2D Random Bond Ising Model. https://doi.org/10.1209/0295-5075%2F27%2F3%2F004

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Accessing the Gluon Momentum Fraction of Nucleons through the Gradient Flow

We calculate the gluon momentum fraction of the nucleon using lattice quantum chromodynamics (QCD), with a nonperturbative renormalization technique based on the gradient flow. The gluon momentum fraction is determined on a single Wilson-clover ensemble using Nf = 2+1 flavors with pion mass 358 MeV and lattice spacing 0.094 fm. We employ the variational method to reduce excited-state contamination and apply the distillation framework to ensure a large operator basis. To reduce systematic uncertainties, we apply Bayesian model averaging to all fit procedures. We apply matching coefficients to the flow-time dependent lattice results to recover the gluon momentum fraction in the MS-scheme at 2 GeV. Our final result is _g(μ= 2 GeV) = 0.482(35), where we quote only statistical uncertainties.

hep-lat

Chiral Magnetic Effect and Negative Magnetoresistance across the phase diagram of finite-density SU(2) gauge theory

We study the signatures of the Chiral Magnetic Effect (CME) in $SU(2)$ gauge theory with $N_f = 2$ flavours of dynamical fermions at finite temperature $T$, quark chemical potential $μ$ and a weak external magnetic field $e B$. We consider both the correlator of the axial density and the vector current, which gives direct access to the out-of-equilibrium CME, and the correlator of two vector currents, which probes the CME indirectly via the enhancement of the longitudinal electric conductivity (Negative Magnetoresistance, NMR). We find that the CME response extracted from the vector-axial correlator exhibits a rather weak dependence on temperature and density in the quark-gluon plasma regime, and is very close to the universal value for free massless quarks. The CME appears to be mildly suppressed at low temperatures in the hadronic phase. In contrast, the NMR behaves in a qualitatively different way across the phase diagram, and is strongly suppressed at either large densities or temperatures. The magnitude of the NMR response appears to be considerably smaller than the prediction based on the lowest Landau level calculation for free quarks. Our findings suggest that for relatively small magnetic field strengths $e B \lesssim m_π^2$ the relation between the CME and NMR might not be as direct as expected. We also do not find statistically significant indications for an enhancement of the CME or NMR strength in the vicinity of the crossover or second-order phase transition lines in the $(μ, T)$ phase diagram.

hep-lat

Predicting the spectrum and decay constants of positive-parity heavy-strange mesons using domain-wall fermions

We present a lattice-QCD calculation of the masses and decay constants of the positive-parity heavy-strange mesons $D^*_{s0}$, $D_{s1}$, $B^*_{s0}$, and $B_{s1}$. The calculations are performed with domain-wall fermions for the light and strange quarks and an anisotropic clover action for the charm and bottom quarks. We use seven different RBC/UKQCD ensembles with pion masses ranging from a near-physical 139 MeV up to 431 MeV. We consider two different analysis types, with or without two-meson operators at the source. We observe the expected below-threshold ground states. The fits without the two-meson operators appear to be more stable, but may overestimate the ground-state energies, while preliminary fits with two-meson operators at the source only appear to underestimate the ground-state energies.

hep-lat