Publications de Thomas Willem Jan de Geus

Investigating Criticality in Rock Failure Using Fiber-Optic Strain Sensing

Gradual localization of deformation preceding catastrophic failure can produce precursory signals associated with a phase transition that may be present prior to earthquakes. However, due to the unclear origin of these precursors and the complexity of the ...

2025

Dynamical heterogeneities of thermal creep in pinned interfaces

Matthieu Wyart, Thomas Willem Jan de Geus

Disordered systems under applied loading display slow creep flows at finite temperature. Renormalization group arguments predicted that creep proceeds via thermal avalanches of activated events. Recently, thermal avalanches were argued to control the dynam ...

2025

Armouring of a Frictional Interface by Mechanical Noise

Matthieu Wyart, Thomas Willem Jan de Geus

A dry frictional interface loaded in shear often displays stick–slip. The amplitude of this cycle depends on the probability that a microscopic event nucleates a rupture and on the rate at which microscopic events are triggered. The latter is determined by ...

2024

Scaling theory for the statistics of slip at frictional interfaces

Matthieu Wyart, Thomas Willem Jan de Geus

Slip at a frictional interface occurs via intermittent events. Understanding how these events are nucleated, can propagate, or stop spontaneously remains a challenge, central to earthquake science and tribology. In the absence of disorder, rate-and-state a ...

AMER PHYSICAL SOC2022

Scaling Description of Creep Flow in Amorphous Solids

Marko Popovic, Matthieu Wyart, Wencheng Ji, Thomas Willem Jan de Geus

Amorphous solids such as coffee foam, toothpaste, or mayonnaise display a transient creep flow when a stress E is suddenly imposed. The associated strain rate is commonly found to decay in time as gamma_ -t-nu, followed either by arrest or by a sudden flui ...

AMER PHYSICAL SOC2022

Mean-field description for the architecture of low-energy excitations in glasses

Matthieu Wyart, Wencheng Ji, Thomas Willem Jan de Geus, Elisabeth Agoritsas

In amorphous materials, groups of particles can rearrange locally into a new stable configuration. Such elementary excitations are key as they determine the response to external stresses, as well as to thermal and quantum fluctuations. Yet, understanding w ...

2022

Thermally activated flow in models of amorphous solids

Marko Popovic, Matthieu Wyart, Wencheng Ji, Thomas Willem Jan de Geus

Amorphous solids yield at a critical value Sigma(c) of the imposed stress Sigma through a dynamical phase transition. While sharp in athermal systems, the presence of thermal fluctuations leads to the rounding of the transition and thermally activated flow ...

AMER PHYSICAL SOC2021

Improving the initial guess for the Newton-Raphson protocol in time-dependent simulations

Thomas Willem Jan de Geus

ACADEMIC PRESS INC ELSEVIER SCIENCE2020

Thermal origin of quasilocalized excitations in glasses

Marko Popovic, Matthieu Wyart, Wencheng Ji, Thomas Willem Jan de Geus, Elisabeth Agoritsas

Key aspects of glasses are controlled by the presence of excitations in which a group of particles can rearrange. Surprisingly, recent observations indicate that their density is dramatically reduced and their size decreases as the temperature of the super ...

2020

Energy-based comparison between the Fourier-Galerkin method and the finite element method

Thomas Willem Jan de Geus

The Fourier-Galerkin method (in short FFTH) has gained popularity in numerical homogenisation because it can treat problems with a huge number of degrees of freedom. Because the method incorporates the fast Fourier transform (FFT) in the linear solver, it ...

ELSEVIER2020

How collective asperity detachments nucleate slip at frictional interfaces

Marko Popovic, Matthieu Wyart, Wencheng Ji, Thomas Willem Jan de Geus

Sliding at a quasi-statically loaded frictional interface can occur via macroscopic slip events, which nucleate locally before propagating as rupture fronts very similar to fracture. We introduce a microscopic model of a frictional interface that includes ...

National Academy of Sciences2019

Analysis of deposited layers with deuterium and impurity elements on samples from the divertor of JET with ITER-like wall

Patrick Blanchard, Basil Duval, Ambrogio Fasoli, Yves Martin, Richard Pitts, Olivier Sauter, Henri Weisen, Robin Humphry-Baker, Stefano Coda, Partha Dutta, Marco Wischmeier, Jan Horacek, Vlad Trifa, Yann Camenen, Jonathan Graves, Duccio Testa, Magalie Diane Bassan, Sun Hee Kim, Mikhail Maslov, Javier García Hernández, David Pfefferlé, Fernando Cortes Salazar, Petre Alexandru Arion, Jose Felix Vega Stavro, Lenke Horváth, Hugo Augusto Penedones Fernandes, Stéphanie Prior, Philippe Janson, Daniel Scott Alessi, Matthew Brown, Philippe Jean Buchs, Lorenzo Anton-Louis Talà, Mario Joe Lehmann, Pamela Solange Valdés Undurraga, Michael Oliver Reinke, Jonnathan Cesar Hidalgo Acosta, Wei Tang, Albano António De Abreu E Presa De Castro E Sousa, Lyne Moser, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

Tritium distributions on W-coated divertor tiles used in the third JET ITER-like wall campaign

Patrick Blanchard, Basil Duval, Ambrogio Fasoli, Yves Martin, Richard Pitts, Olivier Sauter, Henri Weisen, Robin Humphry-Baker, Stefano Coda, Partha Dutta, Marco Wischmeier, Vlad Trifa, Yann Camenen, Jonathan Graves, Duccio Testa, Magalie Diane Bassan, Sun Hee Kim, Mikhail Maslov, Javier García Hernández, David Pfefferlé, Fernando Cortes Salazar, Petre Alexandru Arion, Jose Felix Vega Stavro, Lenke Horváth, Hugo Augusto Penedones Fernandes, Stéphanie Prior, Philippe Janson, Daniel Scott Alessi, Matthew Brown, Philippe Jean Buchs, Lorenzo Anton-Louis Talà, Mario Joe Lehmann, Pamela Solange Valdés Undurraga, Michael Oliver Reinke, Jonnathan Cesar Hidalgo Acosta, Wei Tang, Albano António De Abreu E Presa De Castro E Sousa, Lyne Moser, Dalziel Joseph Wilson, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

Population modelling of the He II energy levels in tokamak plasmas: I. Collisional excitation model

Patrick Blanchard, Basil Duval, Ambrogio Fasoli, Yves Martin, Richard Pitts, Olivier Sauter, Henri Weisen, Robin Humphry-Baker, Stefano Coda, Partha Dutta, Marco Wischmeier, Jan Horacek, Vlad Trifa, Yann Camenen, Jonathan Graves, Duccio Testa, Magalie Diane Bassan, Sun Hee Kim, Mikhail Maslov, Javier García Hernández, David Pfefferlé, Fernando Cortes Salazar, Petre Alexandru Arion, Jose Felix Vega Stavro, Lenke Horváth, Hugo Augusto Penedones Fernandes, Stéphanie Prior, Philippe Janson, Daniel Scott Alessi, Matthew Brown, Philippe Jean Buchs, Lorenzo Anton-Louis Talà, Mario Joe Lehmann, Pamela Solange Valdés Undurraga, Michael Oliver Reinke, Jonnathan Cesar Hidalgo Acosta, Wei Tang, Albano António De Abreu E Presa De Castro E Sousa, Lyne Moser, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

Theory for the density of interacting quasilocalized modes in amorphous solids

Marko Popovic, Matthieu Wyart, Wencheng Ji, Thomas Willem Jan de Geus

Quasilocalized modes appear in the vibrational spectrum of amorphous solids at low frequency. Though never formalized, these modes are believed to have a close relationship with other important local excitations, including shear transformations and two-lev ...

AMER PHYSICAL SOC2019

Neutron spectroscopy measurements of 14 MeV neutrons at unprecedented energy resolution and implications for deuterium-tritium fusion plasma diagnostics

Patrick Blanchard, Basil Duval, Ambrogio Fasoli, Yves Martin, Richard Pitts, Olivier Sauter, Henri Weisen, Stefano Coda, Marco Wischmeier, Jan Horacek, Vlad Trifa, Yann Camenen, Jonathan Graves, Duccio Testa, Sun Hee Kim, Mikhail Maslov, Javier García Hernández, David Pfefferlé, Petre Alexandru Arion, Jose Felix Vega Stavro, Lenke Horváth, Hugo Augusto Penedones Fernandes, Stéphanie Prior, Philippe Janson, Daniel Scott Alessi, Matthew Brown, Philippe Jean Buchs, Lorenzo Anton-Louis Talà, Mario Joe Lehmann, Pamela Solange Valdés Undurraga, Jonnathan Cesar Hidalgo Acosta, Wei Tang, Albano António De Abreu E Presa De Castro E Sousa, Lyne Moser, Dalziel Joseph Wilson, Justin Robert Young, Jonathan Marc Philippe Faustin, Federico Nespoli, Alexis Gérald Page, , , , , , , , , , , , , , , , , , , , , , ,

Elastoplastic description of sudden failure in athermal amorphous materials during quasistatic loading

Marko Popovic, Matthieu Wyart, Thomas Willem Jan de Geus

The response of amorphous materials to an applied strain can be continuous or instead discontinuous if the initial configuration is very stable. We study theoretically how such a stress drop emerges as the system's initial stability is increased. We show t ...

AMER PHYSICAL SOC2018

14 MeV calibration of JET neutron detectors-phase 1: calibration and characterization of the neutron source

Patrick Blanchard, Basil Duval, Ambrogio Fasoli, Yves Martin, Richard Pitts, Olivier Sauter, Henri Weisen, Robin Humphry-Baker, Stefano Coda, Partha Dutta, Marco Wischmeier, Jan Horacek, Vlad Trifa, Yann Camenen, Jonathan Graves, Duccio Testa, Magalie Diane Bassan, Sun Hee Kim, Mikhail Maslov, Javier García Hernández, David Pfefferlé, Fernando Cortes Salazar, Petre Alexandru Arion, Jose Felix Vega Stavro, Lenke Horváth, Hugo Augusto Penedones Fernandes, Stéphanie Prior, Philippe Janson, Daniel Scott Alessi, Matthew Brown, Philippe Jean Buchs, Lorenzo Anton-Louis Talà, Mario Joe Lehmann, Pamela Solange Valdés Undurraga, Michael Oliver Reinke, Jonnathan Cesar Hidalgo Acosta, Wei Tang, Albano António De Abreu E Presa De Castro E Sousa, Lyne Moser, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

Finite strain FFT-based non-linear solvers made simple

Thomas Willem Jan de Geus

Computational micromechanics and homogenization require the solution of the mechanical equilibrium of a periodic cell that comprises a (generally complex) microstructure. Techniques that apply the Fast Fourier Transform have attracted much attention as the ...

Elsevier2017