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TZID:Europe/Paris
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BEGIN:VEVENT
UID:0-717@lptms.universite-paris-saclay.fr
DTSTART:20200121T110000Z
DTEND:20200121T120000Z
DTSTAMP:20191220T085605Z
URL:http://www.lptms.universite-paris-saclay.fr/seminars/seminaire-du-lptm
s-baruch-meerson/
SUMMARY:Séminaire du LPTMS: Baruch Meerson - Salle des séminaires du FAST
et du LPTMS\, bâtiment Pascal n°530 - 21 Jan 20 11:00
DESCRIPTION:Geometrical optics of constrained Brownian motion: three short
stories\nBaruch Meerson (Racah Institute of Physics\, Hebrew University of
Jerusalem)\n\nThe optimal fluctuation method — essentially geometrical
optics — gives a deep insight into large deviations of Brownian motion\,
and it achieves this purpose by simple means. Here we illustrate these
points by telling three short stories about Brownian motions\, ``pushed" i
nto a large-deviation regime by constraints.\n\nStory 1 deals with a long-
time survival of a Brownian particle in 1 + 1 dimension against absorption
by a wall which advances according to a power law xw(t)~ t&gamma\;\, wher
e &gamma\; > 1/2. We also calculate the large deviation function (LDF) of
the particle position at an earlier time\, conditional on the survival by
a later time.\n\nStory 2 addresses a stretched Brownian motion above an a
bsorbing obstacle in the plane. We compute the short-time LDF of the posit
ion of the surviving Brownian particle at an intermediate point.\n\nIn sto
ry 3 we compute the short-time LDF of the winding angle of a Brownian par
ticle wandering around a reflecting disk in the plane.\n\nIn all three sto
ries we uncover singularities of the LDFs which can be interpreted as dyna
mical phase transitions and which have a simple geometric origin. We also
use the small-deviation limit of the geometrical optics to reconstruct the
distribution of typical fluctuations. We argue that\, in stories 1 and 2\
, this is the Ferrari–Spohn distribution.\n\nThe talk is based on a rece
nt paper by B. Meerson and N. R. Smith\, J. Phys. A: Math. Theor. 52\, 415
001 (2019).
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
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