# Matthieu MangeatUniversität des Saarlandes | UKS · Department of Theoretical Physics

Matthieu Mangeat

PhD in Physics

## About

38

Publications

1,768

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150

Citations

Citations since 2016

Introduction

Additional affiliations

November 2018 - present

October 2015 - September 2018

February 2014 - July 2014

## Publications

Publications (38)

Jamming commonly occurs in a system of tiny moving particles or large objects, or even living creatures gather in a place in significant numbers and tend to become immobile. One can think of various systems, ranging from sand piles and foams to traffic jams exhibiting such features. Most familiar among all these is the traffic jam that generally ar...

We consider the two-species Vicsek model (TSVM) consisting of two kinds of self-propelled particles, A and B, that tend to align with particles from the same species and to anti-align with the other. The model shows a flocking transition that is reminiscent of the original Vicsek model: it has a liquid-gas phase transition and displays micro-phase...

We study the off-lattice two-dimensional q-state active clock model (ACM) as a natural discretization of the Vicsek model (VM) [T. Vicsek et al., Phys. Rev. Lett. 75, 1226 (1995)] describing flocking. The ACM consists of particles able to move in the plane in a discrete set of q equidistant angular directions, as in the active Potts model (APM) [S....

The paradigmatic model for heterogeneous media used in diffusion studies is built from reflecting obstacles and surfaces. It is well known that the crowding effect produced by these reflecting surfaces slows the dispersion of Brownian tracers. Here, using a general adsorption desorption model with surface diffusion, we show analytically that making...

We consider the off-lattice two-dimensional q-state active clock model (ACM) as a natural discretization of the Vicsek model (VM) describing flocking. The ACM consists of particles able to move in the plane in a discrete set of q equidistant angular directions, as in the active Potts model (APM), with an alignment interaction inspired by the ferrom...

We consider the two-dimensional $q$-state active clock model (ACM) as a natural discretization of the Vicsek model (VM) describing flocking. The ACM consists of particles able to move in the plane in a discrete set of $q$ equidistant angular directions, as in the active Potts model (APM), with an alignment interaction inspired by the ferromagnetic...

The paradigmatic model for heterogeneous media used in diffusion studies is built from reflecting obstacles and surfaces. It is well known that the crowding effect produced by these reflecting surfaces slows the dispersion of Brownian tracers. Here, using a general adsorption desorption model with surface diffusion, we show analytically that making...

We revisit the classic problem of the effective diffusion constant of a Brownian particle in a square lattice of reflecting impenetrable hard disks. This diffusion constant is also related to the effective conductivity of non-conducting and infinitely conductive disks in the same geometry. We show how a recently derived Green's function for the per...

Optically trapped particles are often subject to a non-conservative scattering force arising from radiation pressure. In this paper, we present an exact solution for the steady state statistics of an overdamped Brownian particle subjected to a commonly used force field model for an optical trap. The model is the simplest of its kind that takes into...

Intracellular transport in living cells is often spatially inhomogeneous with an accelerated effective diffusion close to the cell membrane and a ballistic motion away from the centrosome due to active transport along actin filaments and microtubules, respectively. Recently it was reported that the mean first passage time (MFPT) for transport to a...

Optically trapped particles are often subject to a non-conservative scattering force arising from radiation pressure. In this paper we present an exact solution for the steady state statistics of an overdamped Brownian particle subjected to a commonly used force field model for an optical trap. The model is the simplest of its kind that takes into...

Updated version of the poster presented during the Virtual DPG Spring Meeting 2021, untitled "Narrow escape problem in two-shell circular domains".

Intracellular transport in living cells is often spatially inhomogeneous with an accelerated effective diffusion close to the cell membrane and a ballistic motion away from the centrosome due to active transport along actin filaments and microtubules, respectively. Recently it was reported that the mean first passage time (MFPT) for transport to a...

We study the $q$-state active Potts model (APM) on a two-dimensional lattice in which self-propelled particles have $q$ internal states corresponding to the $q$ directions of motion. A local alignment rule inspired by the ferromagnetic $q$-state Potts model and self-propulsion via biased diffusion according to the internal particle states leads to...

We study the q-state active Potts model (APM) on a two-dimensional lattice in which self-propelled particles have q internal states corresponding to the q directions of motion. A local alignment rule inspired by the ferromagnetic q-state Potts model and self-propulsion via biased diffusion according to the internal particle states elicits collectiv...

We study the active 4-state Potts model (APM) on the square lattice in which active particles have four internal states corresponding to the four directions of motion. A local alignment rule inspired by the ferromagnetic 4-state Potts model and self-propulsion via biased diffusion according to the internal particle states leads to flocking at high...

We revisit the classic problem of the effective diffusion constant of a Brownian particle in a square lattice of reflecting impenetrable hard disks. This diffusion constant is also related to the effective conductivity of non-conducting and infinitely conductive disks in the same geometry. We show how a recently derived Green’s function for the per...

We study the active q-state Potts model (APM) with q = 4 in two-dimensions. The active particles can change their internal states and undergo a nearest neighbor biased diffusion leading to a flocking model. The flocking dynamics is exploited to probe the liquid-gas phase transition in the APM with an intermediate liquid-gas co-existence phase. We c...

The stochastic motion of particles in living cells is often spatially inhomogeneous with a higher effective diffusivity in a region close to the cell boundary due to active transport along actin filaments. As a first step to understand the consequence of the existence of two compartments with different diffusion constant for stochastic search probl...

The stochastic motion of particles in living cells is often spatially inhomogeneous with a higher effective diffusivity in a region close to the cell boundary due to active transport along actin filaments. As a first step to understand the consequence of the existence of two compartments with different diffusion constant for stochastic search probl...

The forces acting on optically trapped particles are commonly assumed to be conservative. Nonconservative scattering forces induce toroidal currents in overdamped liquid environments, with negligible effects on position fluctuations. However, their impact in the underdamped regime remains unexplored. Here, we study the effect of nonconservative sca...

We consider a model of a particle trapped in a harmonic optical trap but with the addition of a nonconservative radiation induced force. This model is known to correctly describe experimentally observed trapped particle statistics for a wide range of physical parameters, such as temperature and pressure. We theoretically analyze the effect of nonco...

The dispersion of Brownian particles in heterogeneous media is a widely studied problem which appears in many contexts (chemical reactions, biological systems, zeolites, porous media, pollutant spreading, ...). A cloud of particles disperses over time without reaching the Boltzmann equilibrium distribution and its spreading is then characterized by...

We consider a model of a particle trapped in a harmonic optical trap but with the addition of a non-conservative radiation induced force. This model is known to correctly describe experimentally observed trapped particle statistics for a wide range of physical parameters such as temperature and pressure. We theoretically analyse the effect of non-c...

As a first approximation, the forces acting on optically trapped particles are commonly assumed to be conservative. The influence of the nonconservative force has been shown to be negligible in overdamped liquid environments. However, its impact in the underdamped regime remains unexplored. Here, we experimentally study the combined effects of grad...

The effective diffusivity of Brownian tracer particles confined in periodic micro-channels is smaller than the microscopic diffusivity due to entropic trapping. Here, we study diffusion in two-dimensional periodic channels whose cross section presents singular points, such as abrupt changes of radius or the presence of thin walls, with openings, de...

Cette thèse vise à caractériser la dynamique stochastique hors-équilibre de particules browniennes sous l’effet de confinement. Ce confinement est appliqué ici par des potentiels attractifs ou des frontières imperméables créant des barrières entropiques. Dans un premier temps, nous regardons la dispersion de particules sans interactions dans les mi...

The effective diffusivity of Brownian tracer particles confined in periodic micro-channels is smaller than the microscopic diffusivity due to entropic trapping. Here, we study diffusion in two-dimensional periodic channels whose cross-section presents singular points, such as abrupt changes of radius or the presence of thin walls, with openings, de...

We examine the dispersion of Brownian particles in a symmetric two dimensional channel, this classical problem has been widely studied in the literature using the so called Fick-Jacobs' approximation and its various improvements. Most studies rely on the reduction to an effective one dimensional diffusion equation, here we drive an explicit formula...

The effective diffusivity D e of tracer particles diffusing in periodically corrugated axisymmetric two- and three-dimensional channels is studied. The majority of the previous studies of this class of problems are based on perturbative analyses about narrow channels, where the problem can be reduced to an effectively one-dimensional one. Here we s...

Natural killer (NK) cells play a central role during innate immune responses by eliminating pathogen-infected or tumorigenic cells. In the microenvironment, NK cells encounter not only target cells but also other cell types including non-target bystander cells. The impact of bystander cells on NK killing efficiency is, however, still elusive. In th...

By means of a systematic expansion in $1/d$ around the infinite-dimensional
solution, we obtain an approximation scheme to compute properties of glasses in
low dimensions. The resulting equations take as input the thermodynamic and
structural properties of the equilibrium liquid, and from this they allow one
to compute properties of the glass. They...

## Projects

Projects (2)

Flocking transition exhibited by active models and it's application to biological systems.

Characterize the dispersion of Brownian particles in periodic microchannels and regular obstacle parks by studying the late time effective diffusivity, from exact Kubo formulas.