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35
Sep 24, 2013
09/13
by
Anatoly M. Kamchatnov; Yaroslav V. Kartashov
texts
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Nonlinear wave patterns generated by the flow of polariton condensate past an obstacle are studied for quasi-one-dimensional microcavity geometry. It is shown that pumping and nonlinear damping play a crucial role in this process leading to sharp differences in subsonic and supersonic regimes. Subsonic flows result in a smooth disturbance of the equilibrium condensate around the obstacle whereas supersonic flow generates a dispersive shock wave in the flow upstream the obstacle and a long...
Source: http://arxiv.org/abs/1112.4142v1
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41
Sep 23, 2013
09/13
by
Yaroslav V. Kartashov; Vladimir V. Konotop; Lluis Torner
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We address stationary patterns in exciton-polariton condensates supported by a narrow external pump beam, and we discover that even in the absence of trapping potentials, such condensates may support stable localized stationary dissipative solutions (quasi-compactons), whose field decays faster than exponentially or even vanishes everywhere outside the pump spot. More general conditions lead to dissipative solitons which may display bistability. The bistability in exciton-polariton condensates,...
Source: http://arxiv.org/abs/1212.1287v1
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93
Jul 20, 2013
07/13
by
Yaroslav V. Kartashov; Vladimir V. Konotop; Victor A. Vysloukh
texts
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We report dissipative surface solitons forming at the interface between a semi-infinite lattice and a homogeneous Kerr medium. The solitons exist due to balance between amplification in the near-surface lattice channel and two-photon absorption. The stable dissipative surface solitons exist in both focusing and defocusing media, when propagation constants of corresponding states fall into a total semi-infinite and or into one of total finite gaps of the spectrum (i.e. in a domain where...
Source: http://arxiv.org/abs/1007.3602v1
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28
Sep 23, 2013
09/13
by
Yaroslav V. Kartashov; Vladimir V. Konotop; Victor A. Vysloukh
texts
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We show that the balance between localized gain and nonlinear cubic dissipation in the twodimensional nonlinear Schrodinger equation allows for existence of stable two-dimensional localized modes which we identify as solitons. Such modes exist only when the gain is strong enough and the energy flow exceeds certain threshold value. The observed solitons neither undergo diffractive spreading nor collapse. Above the critical value of the gain the symmetry breaking occurs and asymmetric dissipative...
Source: http://arxiv.org/abs/1012.0844v1
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33
Sep 18, 2013
09/13
by
Dmitry A. Zezyulin; Yaroslav V. Kartashov; Vladimir V. Konotop
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We present a variety of dissipative solitons and breathing modes in a medium with localized gain and homogeneous linear dissipation. The system posses a number of unusual properties, like exponentially localized modes in both focusing and defocusing media, the existence of modes in focusing media at negative propagation constant values, the simultaneous existence of stable symmetric and anti-symmetric localized modes when the gain landscape possesses two local maxima, as well as the existence...
Source: http://arxiv.org/abs/1102.5222v1
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2.0
Jun 30, 2018
06/18
by
Yaroslav V. Kartashov; Vladimir V. Konotop; Dmitry A. Zezyulin
texts
eye 2
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Spin-orbit (SO) coupling can be introduced in a Bose--Einstein condensate (BEC) as a gauge potential acting only in a localized spatial domain. Effect of such a SO "defect" can be understood by transforming the system to the integrable vector model. The properties of the SO-BEC change drastically if the SO defect is accompanied by the Zeeman splitting. In such a non-integrable system, the SO defect qualitatively changes the character of soliton interactions and allows for formation of...
Topics: Quantum Gases, Nonlinear Sciences, Pattern Formation and Solitons, Condensed Matter
Source: http://arxiv.org/abs/1411.7322
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46
Sep 21, 2013
09/13
by
Yaroslav V. Kartashov; Vladimir V. Konotop; Victor A. Vysloukh
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We address one-dimensional soliton formation in the cubic nonlinear medium with two-photon absorption and transversally inhomogeneous gain landscape consisting of a single or several amplifying channels. Existence of the solitons requires certain threshold gain while the properties of solitons strongly depend on whether the number of the amplifying channels is odd or even. In the former case an increase of the gain leads to a symmetry breaking, which occurs through the pitchfork bifurcation,...
Source: http://arxiv.org/abs/1104.0944v1
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6.0
Jun 28, 2018
06/18
by
Yaroslav V. Kartashov; Vladimir V. Konotop; Boris A. Malomed
texts
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We report on new types of two-component one-dimensional dark solitons (DSs) in a model of a dual-core waveguide with normal group-velocity dispersion and Kerr nonlinearity in both cores, the coupling between which is dispersive too. In the presence of the dispersive coupling, quiescent DSs supported by the zero-frequency background are always gray, being stable with the out-of-phase background, i.e., for opposite signs of the fields in the cores. On the contrary, the background with a nonzero...
Topics: Nonlinear Sciences, Physics, Condensed Matter, Pattern Formation and Solitons, Optics, Other...
Source: http://arxiv.org/abs/1508.04607
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2.0
Jun 30, 2018
06/18
by
Dmitry A. Zezyulin; Yaroslav V. Kartashov; Vladimir V. Konotop
texts
eye 2
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A dual-core waveguide with balanced gain and loss in different arms and with intermodal coupling is considered. The system is not invariant under the conventional $PT$ symmetry but obeys $CPT$ symmetry where an additional spatial inversion $C$ corresponds to swapping the coupler arms. We show that second-order dispersion of coupling allows for unbroken $CPT$ symmetry and supports propagation of stable vector solitons along the coupler. Small-amplitude solitons are found in explicit form. The...
Topics: Pattern Formation and Solitons, Optics, Physics, Nonlinear Sciences
Source: http://arxiv.org/abs/1703.00347
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32
Sep 19, 2013
09/13
by
Yuliy V. Bludov; Yaroslav V. Kartashov; Vladimir V. Konotop
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We report on the existence of nonlinear surface waves which, on the one hand, do not require the threshold energy flow for their excitation, and, on the other hand, extend into media at both sides of the interface at low powers, i.e. can not be reduced to the conventional Tamm states. Such waves can be excited if the refractive index in at least one of the materials forming the interface is periodically modulated, with properly selected modulation depth and frequency. Thresholdless surface...
Source: http://arxiv.org/abs/1009.2788v1
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41
Sep 19, 2013
09/13
by
Yaroslav V. Kartashov; Albert Ferrando; Alexey A. Egorov; Lluis Torner
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We address the existence of vortex solitons supported by azimuthally modulated lattices and reveal how the global lattice discrete symmetry has fundamental implications on the possible topological charges of solitons. We set a general ``charge rule'' using group-theory techniques, which holds for all lattices belonging to a given symmetry group. Focusing in the case of Bessel lattices allows us to derive also a overall stability rule for the allowed vortex solitons.
Source: http://arxiv.org/abs/nlin/0507031v1
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2.0
Jun 29, 2018
06/18
by
Yaroslav V. Kartashov; Vladimir V. Konotop; Dmitry A. Zezyulin; Lluis Torner
texts
eye 2
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The dynamic localization of a two-level atom in a periodic potential under the action of spin-orbit coupling and a weak harmonically-varying linear force is studied. We consider optical and Zeeman potentials that are either in-phase or out-of-phase in two spinor components, respectively. The expectation value for the position of the atom after one oscillation period of the linear force is recovered in authentic resonances or in pseudo-resonances. The frequencies of the linear force...
Topics: Condensed Matter, Quantum Gases
Source: http://arxiv.org/abs/1611.05745
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2.0
Jun 29, 2018
06/18
by
Yaroslav V. Kartashov; Vladimir V. Konotop; Dmitry A. Zezyulin; Lluis Torner
texts
eye 2
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We address Bloch oscillations of a spin-orbit coupled atom in periodic potentials of two types: Optical and Zeeman lattices. We show that in optical lattices the spin-orbit coupling allows controlling the direction of atomic motion and may lead to complete suppression of the oscillations at specific values of the coupling strength. In Zeeman lattices the energy bands are found to cross each other at the boundaries of the Brillouin zone, resulting in period-doubling of the oscillations. In all...
Topics: Quantum Physics, Condensed Matter, Quantum Gases
Source: http://arxiv.org/abs/1610.04716
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39
Sep 21, 2013
09/13
by
Mario I. Molina; Yaroslav V. Kartashov; Lluis Torner; Yuri S. Kivshar
texts
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We study surface modes in semi-infinite chirped two-dimensional photonic lattices in the frame- work of an effective discrete nonlinear model. We demonstrate that the lattice chirp can change dramatically the conditions for the mode localization near the surface, and we find numerically the families of surface modes, in linear lattices, and discrete surface solitons, in nonlinear lattices. We demonstrate that, in a sharp contrast to one-dimensional discrete surface solitons, in two-dimensional...
Source: http://arxiv.org/abs/0712.3179v1
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34
Sep 19, 2013
09/13
by
Yaroslav V. Kartashov; Vladimir V. Konotop; Victor A. Vysloukh; Lluis Torner
texts
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We show that periodic optical lattices imprinted in cubic nonlinear media with strong two-photon absorption and localized linear gain landscapes support stable dissipative defect modes in both focusing and defocusing media. Their shapes and transverse extent are determined by the propagation constant that belongs to a gap of the lattice spectrum which, in turn, is determined by the relation between gain and losses. One-hump and two-hump dissipative defect modes are obtained.
Source: http://arxiv.org/abs/1009.0483v1
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Sep 20, 2013
09/13
by
Zhiyong Xu; Yaroslav V. Kartashov; Lucian-Cornel Crasovan; Dumitru Mihalache; Lluis Torner
texts
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We have found various families of two-dimensional spatiotemporal solitons in quadratically nonlinear waveguide arrays. The families of unstaggered odd, even and twisted stationary solutions are thoroughly characterized and their stability against perturbations is investigated. We show that the twisted and even solutions display instability, while most of the odd solitons show remarkable stability upon evolution.
Source: http://arxiv.org/abs/nlin/0410053v1
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2.0
Jun 30, 2018
06/18
by
Rodislav Driben; Yaroslav V. Kartashov; Boris A. Malomed; Torsten Meier; Lluis Torner
texts
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We show, by means of numerical and analytical methods, that media with a repulsive nonlinearity which grows from the center to the periphery support a remarkable variety of previously unknown complex stationary and dynamical three-dimensional solitary-wave states. Peanut-shaped modulation profiles give rise to vertically symmetric and antisymmetric vortex states, and novel stationary hybrid states, built of top and bottom vortices with opposite topological charges, as well as robust dynamical...
Topics: Nonlinear Sciences, Pattern Formation and Solitons
Source: http://arxiv.org/abs/1405.5977
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45
Sep 21, 2013
09/13
by
Fatkhulla Kh. Abdullaev; Yaroslav V. Kartashov; Vladimir V. Konotop; Dmitry A. Zezyulin
texts
eye 45
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Existence of localized modes supported by the PT-symmetric nonlinear lattices is reported. The system considered reveals unusual properties: unlike other typical dissipative systems it possesses families (branches) of solutions, which can be parametrized by the propagation constant; relatively narrow localized modes appear to be stable, even when the conservative nonlinear lattice potential is absent; finally, the system supports stable multipole solutions.
Source: http://arxiv.org/abs/1104.0276v2
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78
Sep 24, 2013
09/13
by
Zhiyong Xu; Yaroslav V. Kartashov; Lucian-Cornel Crasovan; Dumitru Mihalache; Lluis Torner
texts
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We report on the existence and stability of multicolor lattice vortex solitons constituted by coupled fundamental frequency and second-harmonic waves in optical lattices in quadratic nonlinear media. It is shown that the solitons are stable almost in the entire domain of their existence, and that the instability domain decreases with the increase of the lattice depth. We also show the generation of the solitons, and the feasibility of the concept of lattice soliton algebra.
Source: http://arxiv.org/abs/nlin/0412021v2
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2.0
Jun 30, 2018
06/18
by
Yiqi Zhang; Yaroslav V. Kartashov; Feng Li; Zhaoyang Zhang; Yanpeng Zhang; Milivoj R. Belić; Min Xiao
texts
eye 2
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We address edge states and rich localization regimes available in the one-dimensional (1D) dynamically modulated superlattices, both theoretically and numerically. In contrast to conventional lattices with straight waveguides, the quasi-energy band of infinite modulated superlattice is periodic not only in the transverse Bloch momentum, but it also changes periodically with increase of the coupling strength between waveguides. Due to collapse of quasi-energy bands dynamical superlattices admit...
Topics: Optics, Physics
Source: http://arxiv.org/abs/1703.08938
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55
Sep 20, 2013
09/13
by
Lucian-Cornel Crasovan; Yaroslav V. Kartashov; Dumitru Mihalache; Lluis Torner; Yuri S. Kivshar; Victor M. Perez-Garcia
texts
eye 55
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We show how to generate robust self-sustained clusters of soliton bullets-spatiotemporal (optical or matter-wave) solitons. The clusters carry an orbital angular momentum being supported by competing nonlinearities. The "atoms" forming the "molecule" are fully three-dimensional solitons linked via a staircase-like macroscopic phase. Recent progress in generating atomic-molecular coherent mixing in Bose-Einstein condensates might open potential scenarios for the experimental...
Source: http://arxiv.org/abs/nlin/0301029v1
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40
Sep 20, 2013
09/13
by
Anton S. Desyatnikov; Dragomir N. Neshev; Yuri S. Kivshar; Nina Sagemerten; Denis Traeger; Johannes Jaegers; Cornelia Denz; Yaroslav V. Kartashov
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We analyze theoretically and generate experimentally two-dimensional nonlinear periodic lattices in a photorefractive medium. We demonstrate that the light-induced periodically modulated nonlinear refractive index is highly anisotropic and nonlocal, and it depends on the lattice orientation relative to the crystal axis. We discuss stability of such induced photonic structures and their guiding properties.
Source: http://arxiv.org/abs/nlin/0410030v1
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Sep 22, 2013
09/13
by
Stefano Minardi; Falk Eilenberger; Yaroslav V. Kartashov; Alexander Szameit; Ulrich Röpke; Jens Kobelke; Key Schuster; Hartmut Bartelt; Stefan Nolte; Lluis Torner; Falk Lederer; Andreas Tünnermann; Thomas Pertsch
texts
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We report the first experimental observation of 3D-LBs, excited by femtosecond pulses in a system featuring quasi-instantaneous cubic nonlinearity and a periodic, transversally-modulated refractive index. Stringent evidence of the excitation of LBs is based on time-gated images and spectra which perfectly match our numerical simulations. Furthermore, we reveal a novel evolution mechanism forcing the LBs to follow varying dispersion/diffraction conditions, until they leave their existence range...
Source: http://arxiv.org/abs/1101.0734v1
