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Stability Through Asymmetry: Modulationally Stable Nonlinear Supermodes of Asymmetric non-Hermitian Optical Couplers
Yannis Kominis, Tassos Bountis, Sergej Flach
We analyze the stability of a non-Hermitian coupler with respect to modulational inhomogeneous perturbations in the presence of unbalanced gain and loss. At the parity-time (PT) sy…
Control of wavepacket spreading in nonlinear finite disordered lattices
Rodrigo A. Vicencio And Sergej Flach
In the absence of nonlinearity all normal modes (NMs) of a chain with disorder are spatially localized (Anderson localization). We study the action of nonlinearity, whose strength…
q-breathers in Discrete Nonlinear Schroedinger lattices
K. G. Mishagin, S. Flach, O. I. Kanakov +1
-breathers are exact time-periodic solutions of extended nonlinear systems continued from the normal modes of the corresponding linearized system. They are localized in the spac…
Periodic orbits, localization in normal mode space, and the Fermi-Pasta-Ulam problem
S. Flach, M. V. Ivanchenko, O. I. Kanakov +1
The Fermi-Pasta-Ulam problem was one of the first computational experiments. It has stirred the physics community since, and resisted a simple solution for half a century. The comb…
Discrete surface solitons in two-dimensional anisotropic photonic lattices
Rodrigo A. Vicencio, Sergej Flach, Mario I. Molina +1
We study nonlinear surface modes in two-dimensional {\em anisotropic} periodic photonic lattices and demonstrate that, in a sharp contrast to one-dimensional discrete surface solit…
Tail resonances of FPU q-breathers and their impact on the pathway to equipartition
Tiziano Penati, Sergej Flach
Upon initial excitation of a few normal modes the energy distribution among all modes of a nonlinear atomic chain (the Fermi-Pasta-Ulam model) exhibits exponential localization on…
Fano blockade by a Bose-Einstein condensate in an optical lattice
Rodrigo A. Vicencio, Joachim Brand, Sergej Flach
We study the transport of atoms across a localized Bose-Einstein condensate in a one-dimensional optical lattice. For atoms scattering off the condensate we predict total reflectio…
Scaling properties of -breathers in nonlinear acoustic lattices
O. I. Kanakov, S. Flach, M. V. Ivanchenko +1
Recently -breathers - time-periodic solutions which localize in the space of normal modes and maximize the energy density for some mode vector - were obtained for finite n…
q-breathers in finite two- and three-dimensional nonlinear acoustic lattices
M. V. Ivanchenko, O. I. Kanakov, K. G. Mishagin +1
Nonlinear interaction between normal modes dramatically affects energy equipartition, heat conduction and other fundamental processes in extended systems. In their celebrated exper…
Optical ratchets with discrete cavity solitons
Andrey V. Gorbach, Sergey Denisov, Sergej Flach
We propose a setup to observe soliton ratchet effects using discrete cavity solitons in a one-dimensional array of coupled waveguide optical resonators. The net motion of solitons…
Resonant light-light interaction in slab waveguides: angular filters and spectral hole burning
A. V. Gorbach, V. Fleurov, S. Flach +1
We consider the process of low-power light scattering by optical solitons in a slab waveguide with homogeneous and inhomogeneous refractive index core. We observe resonant reflecti…
Fano resonance in two-dimensional optical waveguide arrays with a bi-modal defect
Rodrigo A. Vicencio, Andrey V. Gorbach, Sergej Flach
We study the two-dimensional extension of the Fano-Anderson model on the basis of a two-dimensional optical waveguide array with a bi-modal defect. We demonstrate numerically the p…
q-Breathers and the Fermi-Pasta-Ulam Problem
S. Flach, M. V. Ivanchenko, O. I. Kanakov
The Fermi-Pasta-Ulam (FPU) paradox consists of the nonequipartition of energy among normal modes of a weakly anharmonic atomic chain model. In the harmonic limit each normal mode c…
Resonant light scattering by optical solitons
S. Flach, V. Fleurov, A. V. Gorbach +1
We consider the process of light scattering by optical solitons in a planar waveguide with homogeneous and inhomogeneous refractive index core. We observe resonant reflection (Fano…