Publications associées à Directed percolation

Critical values in an anisotropic percolation on $\mathbb{Z}^2$

In this thesis, we consider an anisotropic finite-range bond percolation model on

\mathbb{Z}^2

. On each horizontal layer

\{(x,i):x\in\mathbb{Z}\}

for

i\in\mathbb{Z}

, we have edges

\langle(x,i),(y,i)\rangle

for

1\leq|x-y|\leq N

with $N\in\mathbb{N ...

EPFL2021

Unified analysis of topological defects in 2D systems of active and passive disks

Ignacio Pagonabarraga Mora, Pasquale Digregorio

We provide a comprehensive quantitative analysis of localized and extended topological defects in the steady state of 2D passive and active repulsive Brownian disk systems. We show that, both in and out-of-equilibrium, the passage from the solid to the hex ...

ROYAL SOC CHEMISTRY2021

Critical scaling for an anisotropic percolation system on Z(2)

Thomas Mountford, Hao Xue

In this article, we consider an anisotropic finite-range bond percolation model on Z(2). On each horizontal layer {(x, i): x is an element of Z} we have edges for 1

2020

Staggered flux state for rectangular-lattice spin-1/2 Heisenberg antiferromagnets

Henrik Moodysson Rønnow, Dmitri Ivanov, Bastien Dalla Piazza, Noore Elahi Shaik

We investigate the spin-1/2 Heisenberg model on a rectangular lattice, using the Gutzwiller projected variational wave function known as the staggered flux state. Using Monte Carlo techniques, the variational parameters and instantaneous spin-spin correlat ...

AMER PHYSICAL SOC2020

Percolation and Internet Science

Emanuele Massaro

Percolation, in its most general interpretation, refers to the “flow” of something (a physical agent, data or information) in a network, possibly accompanied by some nonlinear dynamical processes on the network nodes (sometimes denoted reaction–diffusion s ...

2019

Quantum phase transitions beyond Landau-Ginzburg theory in one-dimensional space revisited

Christopher Marc Mudry

The phase diagram of the quantum spin-1/2 antiferromagnetic J(1)-J(2) XXZ chain was obtained by Haldane using bosonization techniques [Haldane, Phys. Rev. B 25, 4925 (1982); 26, 5257 (1982)]. It supports three distinct phases for 0

2019

Relation between a heterogeneous percolation model for cylinders and phase separation in the lattice fluid problem

Claudio Grimaldi

A relationship based upon analogy is explored between (i) a lattice-based model for percolation by cylinders that employs distinct site types with unequal occupation probabilities in order to capture heterogeneities in the particle dispersion, and (ii) the ...

2018

Modeling of percolation of globular-equiaxed grains in Al-Cu alloys

Michel Rappaz, Jean-Luc Desbiolles, Christophe Mondoux

A new mesoscopic model able to describe percolation of globular-equiaxed grains, highly relevant for hot tearing formation in castings, has been developed. This model is inspired from the granular model of Sistaninia et al. [1-5] that considers polyhedral ...

Iop Publishing Ltd2015

How colloid-colloid interactions and hydrodynamic effects influence the percolation threshold: A simulation study in alumina suspensions

Paul Bowen

The percolation behavior of alumina suspensions is studied by computer simulations. The percolation threshold phi(c), is calculated, determining the key factors that affect its magnitude: the strength of colloid-colloid attraction and the presence of hydro ...

Elsevier2015

Theory of percolation and tunneling regimes in nanogranular metal films

Claudio Grimaldi

Nanogranular metal composites, consisting of immiscible metallic and insulating phases deposited on a substrate, are characterized by two distinct electronic transport regimes depending on the relative amount of the metallic phase. At sufficiently large me ...

Amer Physical Soc2014

On the Performance of Percolation Graph Matching

Matthias Grossglauser, Lyudmila Yartseva

Graph matching is a generalization of the classic graph isomorphism problem. By using only their structures a graph-matching algorithm finds a map between the vertex sets of two similar graphs. This has applications in the de-anonymization of social and in ...

ACM2013

Limit Behaviour of the Voter Model, Exclusion Process and Regenerative Chains

Samuel Schöpfer

Though the following topics seem unlinked, most of the tools used in this thesis are related to random walks and renewal theory. After introducing the voter model, we consider the parabolic Anderson model with the voter model as catalyst. In GÄRTNER, DEN H ...

EPFL2012

Percolation-to-hopping crossover in conductor-insulator composites

Claudio Grimaldi, Gianluca Ambrosetti

Here, we show that the conductivity of conductor-insulator composites in which electrons can tunnel from each conducting particle to all others may display both percolation and tunneling (i.e., hopping) regimes depending on few characteristics of the compo ...

2010

Metal-Ion Implanted Elastomers : Analysis of Microstructures and Characterization and Modeling of Electrical and Mechanical Properties

Muhamed Niklaus

This thesis reports on the microstructural analysis of metal ion implanted Polydimethylsiloxane (PDMS), and on the characterization and modeling of its electrical and mechanical properties. Low energy (below 35 keV) metal ion implantation into PDMS forms m ...

EPFL2010

On the origin of transport non-universality and piezoresistivity in segregated conductor-insulator composites and application to thick-film resistors

Niklaus Johner

In this thesis we address the description of electrical transport properties of disordered conductor-insulator composites, mostly by numerical Monte Carlo simulations and analytical study of realistic tunnelling-percolation models. Such composites are basi ...

EPFL2009

Optimal percolation of disordered segregated composites

Peter Ryser, Claudio Grimaldi, Thomas Maeder, Niklaus Johner

We evaluate the percolation threshold values for a realistic model of continuum segregated systems, where random spherical inclusions forbid the percolating objects, modellized by hard-core spherical particles surrounded by penetrable shells, to occupy lar ...

2009

Transport exponent in a three-dimensional continuum tunneling-percolation model

Peter Ryser, Claudio Grimaldi, Niklaus Johner

The tunneling-percolation mechanism of conduction in disordered conductor-insulator composites is studied for a realistic continuum model where conducting and impenetrable spherical particles are dispersed in a three-dimensional continuum insulating materi ...

2008

Apparent nonuniversality in finite segregated tunneling-percolaiton models

Peter Ryser, Claudio Grimaldi, Niklaus Johner

We investigate the tunneling-percolation mechanism of DC transport nonuniversality for conducting particles of diameter Φ placed in series within the bonds of length Lof a regular lattice model. When L/Φ→∞ the resulting bond conductance distribution functi ...

2007

Low firing temperature thick-film piezoresistive composites : properties and conduction mechanism

Sonia Vionnet Menot

Thick-film technology has found applications on miniaturised hybrid circuits in various fields (automotive electronics, televisions, ...). This technology is also now widely used for the fabrication of force and pressure sensors that use the piezoresistive ...

EPFL2005