ELFT HÍRADÓ

[tcsaba AT eik.bme.hu]

                               MEGHÍVÓ

          a BME Fizikai Intézete Elméleti Fizika Tanszékének

                            szemináriumára:


                               Géza Ódor
         Institute of Technical Physics and Materials Science
                       Centre for Energy Research


       "Griffiths phases, localization and burstyness in network models"


Quenched disorder is known to play a relevant role in dynamical
processes and phase transitions. By studying the Contact Process (CP)
we showed that Griffiths Phases (GP) and other rare region effects,
leading rather generically to anomalously slow (algebraic,
logarithmic,...) relaxation on Erdos-Renyi networks with explicit
quenched disorder. More surprisingly, we found that GPs can also
emerge solely as the consequence of topological heterogeneity
on generalized small world networks exhibiting finite topological
dimensions. Similar power-law dynamics can also be observed
on scale-free trees in case of disassortative weighting schemes,
in the neighborhood of smeared phase transitions [2].
Recently I have pointed out that localization, described by
quenched mean-field approximations is related to the existence of
rare region effects and GPs in case of Susceptible Infected Susceptible
(SIS) models on various complex networks [3], in particular on
Barabasi-Albert type of networks with aging connections.

Bursty dynamics of agents is shown to appear at criticality or in
extended GPs even in case of Poisson processes. I provide numerical
evidence for power-law type of intercommunication time distributions
by simulating the CP and SIS. This observation suggests that in
case of non-stationary bursty systems the observed non-poissonian
behavior can emerge as the consequence of an underlying hidden poissonian
network process, which is either critical or exhibits strong rare-region
effects [4].

[1] M. A. Munoz, R. Juhasz, C. Castellano, and G, Odor, Phys. Rev.  
Lett. 105, 128701 (2010)
[2] G. Odor, R. Pastor-Satorras, Phys. Rev. E 86, 026117 (2012)
[3] Geza Odor, Phys. Rev. E 87, 042132 (2013)
[4] Geza Odor, Phys. Rev. E 90, 032110 (2014)


Helye: BME Fizikai Intézet, Elméleti Fizika Tanszék
Budafoki út 8. F-épület, III lépcsöház
Szemináriumi szoba

Ideje: 2015. május 8. péntek, 10:15.


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