Yaroslav V. Kartashov

Bio: Yaroslav V. Kartashov is an academic researcher from Russian Academy of Sciences. The author has contributed to research in topics: Soliton & Vortex. The author has an hindex of 54, co-authored 487 publications receiving 11174 citations. Previous affiliations of Yaroslav V. Kartashov include Moscow State University & University of Bath.

Solitons in nonlinear lattices

Abstract: This article offers a comprehensive survey of results obtained for solitons and complex nonlinear wave patterns supported by nonlinear lattices (NLs), which represent a spatially periodic modulation of the local strength and sign of the nonlinearity, and their combinations with linear lattices. A majority of the results obtained, thus far, in this field and reviewed in this article are theoretical. Nevertheless, relevant experimental settings are also surveyed, with emphasis on perspectives for implementation of the theoretical predictions in the experiment. Physical systems discussed in the review belong to the realms of nonlinear optics (including artificial optical media, such as photonic crystals, and plasmonics) and Bose-Einstein condensation. The solitons are considered in one, two, and three dimensions. Basic properties of the solitons presented in the review are their existence, stability, and mobility. Although the field is still far from completion, general conclusions can be drawn. In particular, a novel fundamental property of one-dimensional solitons, which does not occur in the absence of NLs, is a finite threshold value of the soliton norm, necessary for their existence. In multidimensional settings, the stability of solitons supported by the spatial modulation of the nonlinearity is a truly challenging problem, for theoretical and experimental studies alike. In both the one-dimensional and two-dimensional cases, the mechanism that creates solitons in NLs in principle is different from its counterpart in linear lattices, as the solitons are created directly, rather than bifurcating from Bloch modes of linear lattices.

Solitons in PT-symmetric nonlinear lattices

Abstract: The existence of localized modes supported by the $\mathcal{PT}$-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; and finally, the system supports stable multipole solutions.

Frontiers in multidimensional self-trapping of nonlinear fields and matter

Abstract: 2D and 3D solitons and related states, such as quantum droplets, can appear in optical systems, atomic Bose–Einstein condensates (BECs) and liquid crystals, among other physical settings. However, multidimensional solitary states supported by the standard cubic nonlinearity tend to be strongly unstable — a property far less present in 1D systems. Thus, the central challenge is to stabilize multidimensional states, and to that end numerous approaches have been proposed over the years. Most strategies involve non-cubic nonlinearities or using various potentials, including periodic ones. Completely new directions have recently emerged in two-component BECs with spin–orbit coupling, which have been predicted to support stable 2D and metastable 3D solitons. A recent breakthrough is the creation of 3D quantum droplets. These are self-sustained states existing in two-component BECs, stabilized by the quantum fluctuations around the underlying mean-field states. Here, we review recent results in this field and outline outstanding current challenges. Multidimensional self-trapped states exist in many models of physical systems. However, they are highly unstable in media with the universal cubic nonlinearity. We review different mechanisms that may stabilize them, including non-Kerr nonlinearities, spin–orbit coupling and quantum fluctuations, among others.

Soliton Shape and Mobility Control in Optical Lattices

Abstract: We present a progress overview focused on the recent theoretical and experimental advances in the area of soliton manipulation in optical lattices Optical lattices offer the possibility to engineer and to control the diffraction of light beams in media with periodically-modulated optical properties, to manage the corresponding reflection and transmission bands, and to form specially designed defects Consequently, they afford the existence of a rich variety of new families of nonlinear stationary waves and solitons, lead to new rich dynamical phenomena, and offer novel conceptual opportunities for all-optical shaping, switching and routing of optical signals encoded in soliton formats In this overview, we consider reconfigurable optically-induced lattices as well as waveguide arrays made in suitable nonlinear materials We address both, one-dimensional and multi-dimensional geometries We specially target the new possibilities made possible by optical lattices induced by a variety of existing nondiffracting light patterns, we address nonlinear lattices and soliton arrays, and we briefly explore the unique features exhibited by light propagation in defect modes and in random lattices, an area of current topical interest and of potential cross-disciplinary impact

Surface gap solitons.

Abstract: We put forward the existence of surface gap solitons at the interface between uniform media and an optical lattice with defocusing nonlinearity. Such new type of solitons forms when the incident and reflected waves at the interface of the lattice experience Bragg scattering, and feature a combination of the unique properties of both surface waves and gap solitons. We discover that gap surface solitons exist only when the lattice depth exceeds a threshold value, that they can be made completely stable, and that they can form stable bound states.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Bose-Einstein condensation in a gas of sodium atoms

Abstract: Bose-Einstein condensation (BEC) has been observed in a dilute gas of sodium atoms. A Bose-Einstein condensate consists of a macroscopic population of the ground state of the system, and is a coherent state of matter. In an ideal gas, this phase transition is purely quantum-statistical. The study of BEC in weakly interacting systems which can be controlled and observed with precision holds the promise of revealing new macroscopic quantum phenomena that can be understood from first principles.

Topological Photonics

Abstract: Topological photonics is a rapidly emerging field of research in which geometrical and topological ideas are exploited to design and control the behavior of light. Drawing inspiration from the discovery of the quantum Hall effects and topological insulators in condensed matter, recent advances have shown how to engineer analogous effects also for photons, leading to remarkable phenomena such as the robust unidirectional propagation of light, which hold great promise for applications. Thanks to the flexibility and diversity of photonics systems, this field is also opening up new opportunities to realize exotic topological models and to probe and exploit topological effects in new ways. This article reviews experimental and theoretical developments in topological photonics across a wide range of experimental platforms, including photonic crystals, waveguides, metamaterials, cavities, optomechanics, silicon photonics, and circuit QED. A discussion of how changing the dimensionality and symmetries of photonics systems has allowed for the realization of different topological phases is offered, and progress in understanding the interplay of topology with non-Hermitian effects, such as dissipation, is reviewed. As an exciting perspective, topological photonics can be combined with optical nonlinearities, leading toward new collective phenomena and novel strongly correlated states of light, such as an analog of the fractional quantum Hall effect.

Linear and nonlinear waves, by G. B. Whitham. Pp.636. £50. 1999. ISBN 0 471 35942 4 (Wiley).

Abstract: to be done in this area. Face recognition is a problem that scarcely clamoured for attention before the computer age but, having surfaced, has involved a wide range of techniques and has attracted the attention of some fine minds (David Mumford was a Fields Medallist in 1974). This singular application of mathematical modelling to a messy applied problem of obvious utility and importance but with no unique solution is a pretty one to share with students: perhaps, returning to the source of our opening quotation, we may invert Duncan's earlier observation, 'There is an art to find the mind's construction in the face!'.