BEGIN:VCALENDAR
VERSION:2.0
PRODID:icalendar-ruby
CALSCALE:GREGORIAN
METHOD:PUBLISH
BEGIN:VTIMEZONE
TZID:Europe/Vienna
BEGIN:DAYLIGHT
DTSTART:20260329T030000
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=3
TZNAME:CEST
END:DAYLIGHT
BEGIN:STANDARD
DTSTART:20261025T020000
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
TZNAME:CET
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
DTSTAMP:20260717T135750Z
UID:1788267600@ist.ac.at
DTSTART:20260901T150000
DTEND:20260901T160000
DESCRIPTION:Speaker: Jonas Ingmanns\nhosted by Monika Henzinger\nAbstract: 
 Precise microscopic models of physical processes are often too complex to 
 be useful for understanding or simulating phenomena on a macroscopic scale
 . The complexity can be drastically reduced if there is a suitable approxi
 mation which still accurately captures the effective large-scale behavior 
 of the underlying model. This thesis contains contributions to the rigorou
 s justification of such large-scale approximations  or three different mo
 dels. Chapter 2 presents joint work with Federico Cornalba\, Julian Fisch
 er\, and Claudia Raithel. We consider a large system of weakly interacting
  particles\, driven by independent Brownian motions. The physicists Dean a
 nd Kawasaki proposed a strongly singular SPDE to describe fluctuations of 
 the particle density. However\, without a suitable regularization\, the De
 an–Kawasaki equation has been shown to be ill-posed in the sense that it
  does not admit martingale solutions for any continuous initial data. We s
 how that a structure-preserving discretization of the Dean–Kawasaki equa
 tion – acting as a suitable regularization – captures the density fluc
 tuations of the particle system up to arbitrary order in the inverse numbe
 r of particles and a discretization error. Chapter 3 presents joint work 
 with Elisa Davoli and Lorenza D’Elia. We consider a magnetic body consis
 ting of a composite material with a random microstructure. The oscillating
  magnetic properties are encoded in the micromagnetic energy functional wh
 ich is restricted to functions taking values on the sphere\, governing the
  observable states of magnetization. We obtain a qualitative stochastic ho
 mogenization result in the form of Γ-convergence. The Γ-limit is a micro
 magnetic energy functional with constant\, deterministic coefficients\, me
 aning that the magnetic body can be treated as if consisting of a single m
 aterial when the microstructure is small enough. On a technical level\, we
 obtain an analogous result replacing the sphere with other sufficiently re
 gular manifolds.Chapter 4 and Chapter 5 present joint work with Julian Fis
 cher. We consider interface motions driven by curvature and a uniform forc
 ing through a stationary field of possibly impenetrable random obstacles s
 atisfying a finite range of dependence assumption. This process models\, e
 .g.\, the motion of dislocation lines or magnetic domain boundaries in mat
 erials with inhibiting impurities. In Chapter 5\, for dimension  = 2\, we 
 introduce an easy-to-check criterion for general obstacle fields which imp
 lies ballistic behavior. More precisely\, this criterion yields an almost 
 guaranteed effective minimum speed on large scales for the interface motio
 n \, with ‘effective’ meaning that enclosures left behind a main front
  can be ignored. In Chapter 4\, for any dimension  ≥ 2\, assuming such a
 n almost guaranteed effective minimum speed\, we obtain a quantitative sto
 chastic homogenization result in any dimension\, proving that the main fro
 nt can be approximated with a constant-speed motion on large scales.
LOCATION:Office Bldg West / Ground floor / Heinzel Seminar Room (I21.EG.101
 ) and Zoom\, ISTA
ORGANIZER:
SUMMARY:Jonas Ingmanns: Thesis Defense: On the large-scale behavior of inte
 racting particle systems\, composite magnetic materials\, and interface mo
 tions through random obstacle fields
URL:https://talks-calendar.ista.ac.at/events/6560
END:VEVENT
END:VCALENDAR