BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//wp-events-plugin.com//6.4.7.2//EN
TZID:Europe/Paris
X-WR-TIMEZONE:Europe/Paris
BEGIN:VEVENT
UID:0-969@lptms.universite-paris-saclay.fr
DTSTART;TZID=Europe/Paris:20241015T110000
DTEND;TZID=Europe/Paris:20241015T120000
DTSTAMP:20241003T075629Z
URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm
 s-jeremie-klinger-stanford/
SUMMARY:Séminaire du LPTMS :  Jeremie Klinger  (Stanford) - Salle des sém
 inaires du FAST et du LPTMS\, bâtiment Pascal n°530 - 15 Oct 24 11:00
DESCRIPTION:Matching method for first passage observables and diffusion sen
 sitivities of Langevin dynamics\nJeremie Klinger (Stanford University)\nIn
  this talk\, I will discuss two ongoing research projects whose common thr
 ead is dynamical analysis of stochastic systems. The first part 1. will fo
 cus on developping matching methods to reconcile discrepencies between exp
 erimentally measured first passage observables and continuous modelling\; 
 in a second part 2. I will discuss response theory for out-of-equilibrium 
 systems\, for which the fluctuation-dissipation theorem does not hold. Mor
 e precisely\n\n1. Because of limited time resolution in tracking instrumen
 ts\, time series are typical realisations of discrete time stochastic dyna
 mics. In turn\, any experimental estimation of relevant first passage obse
 rvables\, such as mean exit times or commitor functions\, cannot be direct
 ly mapped on a continuous stochastic model without parameter fitting. Star
 ting from the one dimensional commitor function for discrete time and cont
 inuous space random walks\, we show how to make the link with limiting con
 tinuous processes while safeguarding important specific discrete behavior.
  We then show how this one dimensional commitor is the single key to prope
 rly characterizing the limiting behavior of general first passage observab
 les across various dimensions and geometries.\n\n2. Analyzing the response
  properties of systems subject to perturbations provides useful insights o
 n the structural properties of the system\, and is of paramount importance
  in identifying phase transitions. For equilibrium Langevin systems\, the 
 fluctuation-dissipation theorem (FDT) relates response to spontaneous fluc
 tuations\, such that sensitivity analysis can be carried out without actua
 lly perturbing the system. Out of equilibrium\, the FDT does not hold\; ho
 wever we construct general non-equilibrium response estimators that allow 
 sensitivity analysis for both stationnary (NESS) and non stationnary syste
 ms. This estimator is based on the instantaneous score $\nabla \\log \\rho
 _t$ of the system\, a by-now classical object in machine learning\, that c
 an be estimated from system snapshots.
CATEGORIES:seminars
LOCATION:Salle des séminaires du FAST et du LPTMS\, bâtiment Pascal n°53
 0\, rue André Riviere\, Orsay\, 91405\, France
X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=rue André Riviere\, Orsay\
 , 91405\, France;X-APPLE-RADIUS=100;X-TITLE=Salle des séminaires du FAST 
 et du LPTMS\, bâtiment Pascal n°530:geo:0,0
END:VEVENT
BEGIN:VTIMEZONE
TZID:Europe/Paris
X-LIC-LOCATION:Europe/Paris
BEGIN:DAYLIGHT
DTSTART:20240331T030000
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
TZNAME:CEST
END:DAYLIGHT
END:VTIMEZONE
END:VCALENDAR