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WiSe 2019/2020

LocationTopic, SpeakerInvited by
2019-11-21 16:00
  W15 0-023

2019-11-28 16:00
  W15 0-023
Dimensional Reduction and Transient Dynamics in Coupled Heteroclinic Cycles.
Maximilian Voit (Jacobs University Bremen gGmbH) Physics

Modeling complex systems as networks have recently received much attention, as real-world systems usually consist of many coupled units. The dynamics of such coupled systems generically differ from the individual dynamics of single units and collective effects are in the focus of interest. Although heteroclinic cycles emerge robustly in various scenarios (e.g. in population dynamics, fluid dynamics, or game theory), systems of coupled heteroclinic cycles have not been extensively studied up to now.

He will first give a broad introduction to heteroclinic cycles and their dynamics, and subsequently present results on small coupled systems. In spite of their simple structure, they exhibit rich dynamics. In particular interesting is the emergence of different kinds of dimensional reduction, especially toward a synchronized state, and the multistability between them. Furthermore, parameter regions of transient chaos emerge which seems to exhibit non-standard scaling behavior.

Lukas Halekotte
2019-12-05 16:00
  W15 0-023

2019-12-12 16:00
  W15 0-023

2019-12-19 16:00
  W15 0-023

2020-01-09 16:00
  W15 0-023

2020-01-16 16:00
  W15 0-023

2020-01-23 16:00
  W15 0-023

2020-01-30 16:00
  W15 0-023

Past Events:

2019-10-24 16:00
  W15 0-023
Emergence of extreme and superextreme events in the Lienard system
Leo Kingston (Lodz University of Technology, Polen)
Ulrike Feudel
2019-10-29 16:00
  W15 0-023
Extreme events in a network of heterogeneous Josephson junctions
Arindam Mishra (Jadavpur University Kalkata, India)

We observe rare and recurrent large spiking events in a heterogeneous network of superconducting Josephson junctions (JJ) connected through a resistive load and driven by a radio-frequency (rf) current in addition to a constant bias. The intermittent large spiking events show characteristic features of extreme events (EE) since they are larger than a statistically defined significant height. Under the influence of repulsive interactions and an impact of heterogeneity of damping parameters, the network splits into three sub-groups of junctions, one in incoherent rotational, another incoherent librational motion and a third sub-group originating EE. We are able to scan the whole population of junctions with their distinctive individual dynamical features either in EE mode or non-EE mode in parameter space. EE migrates spatially from one to another sub-group of junctions depending upon the repulsive strength and the damping parameter. For weak repulsive coupling, all the junctions originate frequent large spiking events, in rotational motion when the average inter-spike-interval (ISI) is small, but it increases exponentially with repulsive interaction; it largely deviates from its exponential growth at a breakpoint where EE triggers in a sub-group of junctions. The probability density of inter-event-intervals (IEI) in the subgroup exhibits a Poisson distribution. EE originates via bubbling instability of in-phase synchronization.

Ulrike Feudel
2019-11-07 16:00
  W15 0-023
To be announced
Benedikt Luensmann (Max-Planck-Institute for Physics of Complex Systems)

To be announced

Ulrike Feudel
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