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Humboldt-Universität zu Berlin - Mathematisch-Naturwissen­schaft­liche Fakultät - International Research Training Group 1740

IRTG Colloquium (2/12)

Wann 12.06.2012 von 13:00 bis 15:00 (Europe/Berlin / UTC200) iCal
Wo PIK, Main Cupola, Telegrafenberg A31, Potsdam

I want to inform you about our next colloquium, which will take place in Potsdam (PIK, Main Cupola, Telegrafenberg A31) on the 12th of June starting at 1:00 pm.

The speakers are:

 

 


 

Prof. Sudeshna Sinha (IISER Mohali, India)
Scalable ultra-sensitive detection of heterogeneity via coupled bistable dynamics

 

Dr. Awadhesh Prasad (University of Delhi, India)
The phenomenon of amplitude death in coupled nonlinear systems

 

 

Abstracts:


Sudeshna Sinha
Scalable ultra-sensitive detection of heterogeneity via coupled bistable dynamics

We demonstrate how the collective response of N globally coupled bistable elements can strongly reflect the presence of very few non-identical elements in a large network of otherwise identical elements. Counter-intuitively, when there are a small number of elements with natural stable state different from the bulk of the elements, all the elements of the system evolve to the stable state of the minority due to strong coupling. The critical fraction of distinct elements needed to produce this swing shows a sharp transition with increasing N, scaling as 1/sqrt(N). Furthermore, one can find a global bias that allows robust one bit sensitivity to heterogeneity. Importantly, the time needed to reach the attracting state does not increase with the system size. We indicate the relevance of this ultra-sensitive generic phenomenon for massively parallelized applications, such as the determination of the existence of a "needle in a haystack"' by one measurement.



Awadhesh Prasad
The phenomenon of amplitude death in coupled nonlinear systems

Natural systems are rarely isolated, and hence the interaction between such systems have beenextensively studied from both theoretical and experimental points of view in a variety of contexts in the physical, biological, and social sciences. Several interesting new phenomena arise in such interacting systems. Amplitude death (AD) is an important phenomenon that can also occur in coupled nonlinear oscillators when their interaction causes the fixed points to become stable and attracting. In this talk we will review the various routes to AD as well general situations under which AD occurs. We will discuss some control methods that have been employed to either target or avoid steady states in coupled systems.