arXiv subjects

L. Bogacz

Publications and source records attributed to L. Bogacz.

23 records · Page 2Linked to original sources

arXiv2005

A program generating homogeneous random graphs with given weights

We present a program package which generates homogeneous random graphs with probabilities prescribed by the user. The statistical weight of a labeled graph $α$ is given in the form $W(α)=\prod_{i=1}^N p(q_i)$, where $p(q)$ is an arbitrary user function and $q_i$ are the degrees of the graph nodes. The program can be used to generate two types of graphs (simple graphs and pseudo-graphs) from three types of ensembles (micro-canonical, canonical and grand-canonical).

cond-mat.dis-nn↗

arXiv2003

Fermions in 2D Lorentzian Quantum Gravity

We implement Wilson fermions on 2D Lorentzian triangulation and determine the spectrum of the Dirac-Wilson operator. We compare it to the spectrum of the corresponding operator in the Euclidean background. We use fermionic particle to probe the fractal properties of Lorentzian gravity coupled to $c=1/2$ and $c=4$ matter. We numerically determine the scaling exponent of the mass gap $M \sim N^{-1/d_H}$ to be $d_H=2.11(5)$, and $d_H=1.77(3)$ for $c=1/2$ and $c=4$, respectively

hep-lat↗

arXiv2002

Spectrum of the Dirac operator coupled to two-dimensional quantum gravity

We implement fermions on dynamical random triangulation and determine numerically the spectrum of the Dirac-Wilson operator D for the system of Majorana fermions coupled to two-dimensional Euclidean quantum gravity. We study the dependence of the spectrum of the operator (epsilon D) on the hopping parameter. We find that the distributions of the lowest eigenvalues become discrete when the hopping parameter approaches the value 1/sqrt{3}. We show that this phenomenon is related to the behavior of the system in the 'antiferromagnetic' phase of the corresponding Ising model. Using finite size analysis we determine critical exponents controlling the scaling of the lowest eigenvalue of the spectrum including the Hausdorff dimension d_H and the exponent kappa which tells us how fast the pseudo-critical value of the hopping parameter approaches its infinite volume limit.

hep-lat↗

arXiv2001

Dirac operator and Ising model on a compact 2D random lattice

Lattice formulation of a fermionic field theory defined on a randomly triangulated compact manifold is discussed, with emphasis on the topological problem of defining spin structures on the manifold. An explicit construction is presented for the two-dimensional case and its relation with the Ising model is discussed. Furthermore, an exact realization of the Kramers-Wannier duality for the two-dimensional Ising model on the manifold is considered. The global properties of the field are discussed. The importance of the GSO projection is stressed. This projection has to be performed for the duality to hold.

hep-lat↗

arXiv1999

Finite size scaling of the balls in boxes model

We discuss the finite size behaviour in the canonical ensemble of the balls in boxes model. We compare theoretical predictions and numerical results for the finite size scaling of cumulants of the energy distribution in the canonical ensemble and perform a detailed analysis of the first and third order phase transitions which appear for different parameter values in the model.

hep-lat↗