Nonequilibrium fluctuations of a Brownian particle
type: Dataset
description: This thesis describes an experimental study on fluctuations of a Brownian particle immersed in a fluid, confined by optical tweezers and subject to two different kinds of non-equilibrium conditions. We aim to gain a rather general understanding of the relation between spontaneous fluctuations, linear response and total entropy production for processes away from thermal equilibrium. The first part addresses the motion of a colloidal particle driven into a periodic non-equilibrium steady state by a nonconservative force and its response to an external perturbation. The dynamics of the system is analyzed in the context of several generalized fluctuation-dissipation relations derived from different theoretical approaches. We show that, when taking into account the role of currents due to the broken detailed balance, the theoretical relations are verified by the experimental data. The second part deals with fluctuations and response of a Brownian particle in two different aging baths relaxing towards thermal equilibrium: a Laponite colloidal glass and an aqueous gelatin solution. The experimental results show that heat fluxes from the particle to the bath during the relaxation process play the same role of steady state currents as a non-equilibrium correction of the fluctuation-dissipation theorem. Then, the present thesis provides evidence that the total entropy production constitutes a unifying concept which links the statistical properties of fluctuations and the linear response function for non-equilibrium systems either in stationary or non stationary states.
identifier: NNT: 2011ENSL0629
issued: 2026-05-24T06:32:46.883975
language: en
modified: 2026-05-24T06:32:46.883987
contact point: Organization
  fn: CCSD
keyword: aging
keyword: brownian-motion
keyword: colloidal-glasses
keyword: dynamique-de-langevin
keyword: etats-non-stationnaires
keyword: etats-stationnaires-hors-equilibre
keyword: fluctuation-dissipation-theorem
keyword: fluctuation-theorem
keyword: gels-thermoreversibles
keyword: infoeu-reposemanticsdoctoralthesis
keyword: mechanique-statistique-hors-equilibre
keyword: microrheologie
keyword: microrheology
keyword: mouvement-brownien
keyword: nonequilibrium-statistical-mechanics
keyword: nonequilibrium-steady-states
keyword: nonstationary-states
keyword: optical-tweezers
keyword: out-of-equilibrium-systems
keyword: overdamped-langevin-dynamics
keyword: physcondcm-genphysics-physicscondensed-matter-cond-matother-cond-matother
keyword: pinces-optiques
keyword: processus-stochastiques
keyword: stochastic-processes
keyword: systemes-hors-equilibre
keyword: theoreme-de-fluctuation
keyword: theoreme-de-fluctuation-dissipation
keyword: thermoreversible-gels
keyword: theses
keyword: verres-colloidaux
keyword: vieillissement
landing page: https://theses.hal.science/tel-00680302

Nonequilibrium fluctuations of a Brownian particle
type: Distribution
format: HTML
issued: 2026-05-24T06:32:47.062411
modified: 2026-05-24T06:32:46.764829
access URL: https://theses.hal.science/tel-00680302

test_moissonnage_selune
type: Agent