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TZID:Europe/Paris
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BEGIN:VEVENT
UID:1-288@lptms.universite-paris-saclay.fr
DTSTART:20141114T093000Z
DTEND:20141114T123000Z
DTSTAMP:20141103T125729Z
URL:http://www.lptms.universite-paris-saclay.fr/seminars/soutenance-de-the
 se-andrey-lokhov/
SUMMARY:Soutenance de thèse : Andrey Lokhov - IPN-batiment 100\, Auditoriu
 rm - 14 Nov 14 09:30
DESCRIPTION:Dynamic cavity method and problems on graphs\nAndrey Lohhov\, L
 PTMS\nA large number of optimization\, inverse\, combinatorial and out-of-
 equilibrium problems\, arising in the statistical physics of complex syste
 ms\, allow for a convenient representation in terms of disordered interact
 ing variables defined on a certain network. Although a universal recipe fo
 r dealing with these problems does not exist\, the recent years have seen 
 a serious progress in understanding and quantifying an important number of
  hard problems on graphs. A particular role has been played by the concept
 s borrowed from the physics of spin glasses and field theory\, that appear
 ed to be extremely successful in the description of the statistical proper
 ties of complex systems and in the development of efficient algorithms for
  concrete problems.\nIn the first part of the thesis\, we study the out-of
 -equilibrium spreading problems on networks. Using dynamic cavity method o
 n time trajectories\, we show how to derive dynamic message-passing equati
 ons for a large class of models with unidirectional dynamics -- the key pr
 operty that makes the problem solvable. These equations are asymptotically
  exact for locally tree-like graphs and generally provide a good approxima
 tion for real-world networks. We illustrate the approach by applying the d
 ynamic message-passing equations for susceptible-infected-recovered model 
 to the inverse problem of inference of epidemic origin.\nIn the second par
 t of the manuscript\, we address the optimization problem of finding optim
 al planar matching configurations on a line. Making use of field-theory te
 chniques and combinatorial arguments\, we characterize a topological phase
  transition that occurs in the simple Bernoulli model of disordered matchi
 ng. As an application to the physics of the RNA secondary structures\, we 
 discuss the relation of the perfect-imperfect matching transition to the k
 nown molten-glass transition at low temperatures\, and suggest generalized
  models that incorporate a one-to-one correspondence between the contact m
 atrix and the nucleotide sequence\, thus giving sense to the notion of eff
 ective non-integer alphabets.
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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