Thursday, April 16th 
Oleh Omel'chenko (Universität Potsdam) 
Traveling chimera states 
We overview recent results about the traveling chimera states observed in a ring of nonlocally coupled phase oscillators with broken reflection symmetry of the coupling kernel. These states manifest themselves as coherenceincoherence patterns moving along the ring. As the coupling asymmetry grows they undergo a sequence of transformations, which can be adequately explained using the continuum limit OttAntonsen equation. In the context of this equation the chimera states correspond to its smooth traveling wave solutions. Using the mathematical methods from the PDE and integral equations theory we carry out asymptotic analysis of these traveling waves, describe an algorithm for their numerical continuation and explore the spectrum of the corresponding linearized equation. We show that traveling chimera states can lose their stability via fold and Hopf bifurcations. Some of the Hopf bifurcations turn out to be supercritical resulting in the observation of modulated traveling chimera states.

Tuesday, April 30th 
Irina Kmit (HumboldtUniversität zu Berlin) 
Classical bounded and almost periodic solutions to quasilinear firstorder hyperbolic systems 
We consider boundary value problems for quasilinear firstorder onedimensional hyperbolic systems in a strip. The boundary conditions are supposed to be of a smoothing type, in the sense that the L2generalized solutions to the initialboundary value problems become eventually C2smooth for any initial L2data. We investigate small global classical solutions and obtain the existence and uniqueness result under the condition that the evolution family generated by the linearized problem has exponential dichotomy on R. We prove that the dichotomy survives under small perturbations in the leading coefficients of the hyperbolic system. Assuming that the coefficients of the hyperbolic system are almost periodic, we prove that the bounded solution is almost periodic also.

Tuesday, May 28th 
Sebastian Eydam (WIAS Berlin) 
Modelocked solutions and coherence echoes in systems of globallycoupled phase oscillators 
In systems of Kuramoto type globallycoupled phase oscillators with equidistant natural frequencies, one can observe an interesting collective phenomenon below the synchronization threshold. The collective behavior is characterized by sharp pulses in the meanfield amplitude and therefore appropriately called mode locked. We discuss the emergence of this particular type of solution as well as the typical bifurcation scenarios that are found along their stability boundaries. In large ensembles, where the natural frequencies follow from a multimodal distribution, modelocked solutions are observed and the breakdown of the pulsation due to the broadening of the frequency width is explored. Echo phenomena have a long history and are found in various systems with one of the most prominent examples being the appearance of spinechoes. We consider an echotype response phenomenon that occurs after multiple external stimuli in ensembles of phase oscillators below the synchronization threshold. An intuitive explanation of the coherence echo phenomenon in the language of mode locking is given and it is shown that the nonlinear global interaction that supports modelocked solutions can also enhance the echo response significantly.

Tuesday, June 11th 
Matthias Wolfrum (WIAS Berlin) 
Temporal dissipative solitons in systems with time delay 
Tuesday, June 25th 
Stefan Ruschel (TU Berlin) 
Pulsing dynamics of a laser system with delayed feedback 
We consider the Yamada model for an excitable or selfpulsating laser with saturable absorber
in the presence of delayed optical selffeedback. We present some recent results regarding the
stability and bifurcations of periodic light pulses that are sustained in the external cavity feedback
loop, so called external cavity pulse trains.

Friday, July 12th 
Toshiyuki Ogawa (Meiji University, Tokyo) 
Drift bifurcation of traveling waves in a reactiondiffusion system with 3 competing species
Please note that the seminar takes place at 11:15 a.m. at FU Berlin, Arnimallee 3, room 130, 14195 Berlin. 