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The (3+1)-dimensional nonlinear Schrödinger equation with power-law nonlinearities in two kinds of PT - symmetric potentials is investigated, and two kinds of Gaussian-type light bullet (LB) solutions are analytically derived. Based on these analytical solutions, the powers, power-flow densities and the phase switches are discussed. The linear stability analysis and the direct numerical simulation show that LB solutions are stable only when the imaginary parts of PT - symmetric potentials are below some thresholds in the focusing power-law nonlinear media, while they are always unstable in the defocusing power-law nonlinear media. [ABSTRACT FROM AUTHOR]

Two kinds of Gaussian-type light bullet (LB) solutions of the ( 3 + 1 )-dimensional Schrödinger equation with cubic and power-law nonlinearities in PT -symmetric potentials are analytically obtained. The phase switches, powers and transverse power-flow densities of these solutions in homogeneous media are studied. The linear stability analysis of these LB solutions and the direct numerical simulation indicate that LB solutions are stable below some thresholds for the imaginary part of PT -symmetric potentials in the defocusing cubic and focusing power-law nonlinear medium, while they are always unstable for all parameters in other media. Moreover, the broadened and compressed behaviors of LBs in the exponential periodic amplification system and diffraction decreasing system are discussed. Results indicate that LB is more stable for the sign-changing nonlinearity in the exponential periodic amplification system than for the non-sign-changing nonlinearity in the diffraction decreasing system at the same propagation distances. [ABSTRACT FROM AUTHOR]

We obtain analytical solutions that describe self-similar rogue waves for the (1+1)-dimensional nonautonomous nonlinear Schrödinger equation with a linear potential. The explicit functions that describe the evolution of the width, peak, and phase are found exactly, from which it can be seen that the gain-loss parameter has no effect on the motion of rogue waves' phases or their widths, and affects only the evolution of their peaks. We also find that the manipulation of rogue waves can be realized by modulating the values of the maximum accumulated time, Tm, and the accumulated time, T0, with the maximum amplitude of the rogue waves. The controllability for the type of excitation, such as sustainment, recurrence, and annihilation for rogue waves and the transverse position of excitation is exhibited. [ABSTRACT FROM AUTHOR]

With the help of similarity transformation, we obtain analytical spatiotemporal self-similar solutions of the nonautonomous (3+1)-dimensional cubic-quintic Gross-Pitaevskii equation with time-dependent diffraction, nonlinearity, harmonic potential and gain or loss when two constraints are satisfied. These constraints between the system parameters hint that self-similar solutions form and transmit stably without the distortion of shape based on the exact balance between the diffraction, nonlinearity and the gain/loss. Based on these analytical results, we investigate the dynamic behaviours in a periodic distributed amplification system. [ABSTRACT FROM AUTHOR]

Abstract: We present, analytically, self-similar rogue wave solutions (rational solutions) of the inhomogeneous nonlinear Schrödinger equation (NLSE) via a similarity transformation connected with the standard NLSE. Then we discuss the propagation behaviors of controllable rogue waves under dispersion and nonlinearity management. In an exponentially dispersion-decreasing fiber, the postponement, annihilation and sustainment of self-similar rogue waves are modulated by the exponential parameter . Finally, we investigate the nonlinear tunneling effect for self-similar rogue waves. Results show that rogue waves can tunnel through the nonlinear barrier or well with increasing, unchanged or decreasing amplitudes via the modulation of the ratio of the amplitudes of rogue waves to the barrier or well height. [Copyright &y& Elsevier]

Abstract: We investigate exact nonlinear matter wave functions with odd and even parities in the framework of quasi-two-dimensional Bose–Einstein condensates (BECs) with spatially modulated cubic–quintic nonlinearities and harmonic potential. The existence condition for these exact solutions requires that the minimum energy eigenvalue of the corresponding linear Schrödinger equation with harmonic potential is the cutoff value of the chemical potential . The competition between two-body and three-body interactions influences the energy of the localized state. For attractive two-body and three-body interactions, the larger the matter wave order number , the larger the energy of the corresponding localized state. A linear stability analysis and direct simulations with initial white noise demonstrate that, for the same state (fixed ), increasing the number of atoms can add stability. A quasi-stable ground-state matter wave is also found for repulsive two-body and three-body interactions. We also discuss the experimental realization of these results in future experiments. These results are of particular significance to matter wave management in higher-dimensional BECs. [Copyright &y& Elsevier]

Abstract: In this paper, we generalize the exp-function method, which was used to find new exact travelling wave solutions of nonlinear partial differential equations (NPDEs) or coupled nonlinear partial differential equations, to nonlinear differential–difference equations (NDDEs). As an illustration, two series of exact travelling wave solutions of the discrete sine–Gordon equation are obtained by means of the exp-function method. As some special examples, these new exact travelling wave solutions can degenerate into the kink-type solitary wave solutions reported in the open literature. [Copyright &y& Elsevier]

Abstract: Using the extended tanh-function method (ETM) based on mapping method, the variable separation solutions of the -dimensional KdV system are obtained. By further studying, we find that these variable separation solutions, which seem independent, actually depend on each other. Based on the variable separation solution and by choosing appropriate functions, some novel and interesting interactions between special solitons, such as bell-like anti-compacton, peakon-like anti-compacton and compacton-like anti-semifoldon, are investigated. [Copyright &y& Elsevier]

We present several kinds of optical solitary wave solutions for the fourth-order dispersive cubic-quintic nonlinear Schrödinger equation describing the propagation of optical pulses in a medium that exhibits a parabolic nonlinearity law. Among them, apart from some regular fundamental bright solitary wave solutions and dark solitary wave solutions given, there are also two kinds of combined solitary wave solutions, i.e., bright and dark solitary wave and W-shaped solitary wave solutions which describe bright and dark solitary wave properties. It is found that their amplitude may approach nonzero when the time variable approaches infinity. Moreover, when the parameters of the bright and dark solitary wave are selected appropriately, the kink and anti-kink solitary wave solutions, which are first reported in the fourth-order dispersive cubic-quintic nonlinear Schrödinger equation, are discovered. [ABSTRACT FROM AUTHOR]

Utilizing the extended projective Ricatti equation expansion method, abundant variable separation solutions of the (2+1)-dimensional dispersive long wave systems are obtained. From the special variable separation solution (38) and by selecting appropriate functions, new types of interaction between the multi-valued and the single-valued solitons, such as semi-foldon and dromion, semi-foldon and peakon, semi-foldon and compacton are found. Meanwhile, we conclude that the solution v is essentially equivalent to the ’universal” formula (1). [ABSTRACT FROM AUTHOR]

In this paper, we study the existence conditions of the soliton solutions induced by considering the higher-order effects such as the third-order dispersion (TOD), self-steepening (SS), and self-frequency shift arising from stimulated Raman scattering (SRS) simultaneously in optical soliton communication. Based on the Jacobian expansion method, we successfully obtain bright and dark solitons. The results shows that the resultant inclusion is in agreement with Mollenauer et al. [ Physical Review Letters 45 (1980) 1095] when the SRS is not considered; while when the SRS is considered, the existence conditions of the higher-order effects induced bright and dark solitons are not only quite different from those of the group velocity dispersion (GVD)-induced and self-phase modulation (SPM)-induced solitons, but also different from those of the TOD- and SS-induced solitons discussed by Mollenauer et al. [ Physical Review Letters 45 (1980) 1095]. [ABSTRACT FROM AUTHOR]

In this paper, we have utilized the extended Jacobian elliptic function approach to construct seven families of new Jacobian elliptic function solutions for the coupled discrete nonlinear Schrödinger equations. When the modulus m → 1 or 0, some of these obtained solutions degenerate to the soliton solutions (the moving bright-bright and dark-dark solitons), the solitonic solutions and the trigonometric function solutions. This integrable model possesses the moving solitons because there is no PN barrier to block their motion in the lattice. We also find that some solutions in differential-difference equations (DDEs) are essentially identical to the continuous cases, while some solutions such as sec-type and tan-type in differential-difference models present different properties. [ABSTRACT FROM AUTHOR]