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TZID:Europe/Paris
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BEGIN:VEVENT
UID:1-373@lptms.universite-paris-saclay.fr
DTSTART:20150908T100000Z
DTEND:20150908T130000Z
DTSTAMP:20150901T055711Z
URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the
se-caterina-de-bacco/
SUMMARY:Soutenance de thèse : Caterina de Bacco - IPN-batiment 100\, Audit
oriurm - 8 Sep 15 10:00
DESCRIPTION:Decentralized network control\, optimization and random walks o
n networks\nIn the last years several problems been studied at the interfa
ce between statistical physics and computer science. The reason being that
often these problems can be reinterpreted in the language of physics of d
isordered systems\, where a big number of variables interacts through loca
l fields dependent on the state of the surrounding neighborhood. Among the
numerous applications of combinatorial optimisation the optimal routing o
n communication networks is the subject of the first part of the thesis. W
e will exploit the cavity method to formulate efficient algorithms of type
message-passing and thus solve several variants of the problem through it
s numerical implementation. At a second stage\, we will describe a model t
o approximate the dynamic version of the cavity method which allows to dec
rease the complexity of the problem from exponential to polynomial in time
. This will be obtained by using the Matrix Product State formalism of qua
ntum mechanics. Another topic that has attracted much interest in statisti
cal physics of dynamic processes is the random walk on networks. The theor
y has been developed since many years in the case the underneath topology
is a d-dimensional lattice. On the contrary the case of random networks ha
s been tackled only in the past decade\, leaving many questions still open
for answers. Unravelling several aspects of this topic will be the subjec
t of the second part of the thesis. In particular we will study the averag
e number of distinct sites visited during a random walk and characterize i
ts behaviour as a function of the graph topology. Finally\, we will addres
s the rare events statistics associated to random walks on networks by usi
ng the large-deviations formalism. Two types of dynamic phase transitions
will arise from numerical simulations\, unveiling important aspects of thi
s problems. We will conclude outlining the main results of an independent
work developed in the context of out-of-equilibrium physics. A solvable sy
stem made of two Brownian particles surrounded by a thermal bath will be s
tudied providing details about a bath-mediated interaction arising for the
presence of the bath.
CATEGORIES:seminars
LOCATION:IPN-batiment 100\, Auditoriurm\, 15 Rue Georges Clemenceau\, orsay
\, France
GEO:48.698196;2.181773
X-APPLE-STRUCTURED-LOCATION;VALUE=URI;X-ADDRESS=15 Rue Georges Clemenceau\,
orsay\, France;X-APPLE-RADIUS=100;X-TITLE=IPN-batiment 100\, Auditoriurm:
geo:48.698196,2.181773
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