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The dynamics of spin–orbit-coupled Bose–Einstein condensate with parity-time symmetry through a moving obstacle potential is simulated numerically. In the miscible two-component condensate, the formation of the Kármán vortex street is observed in one component, while 'the half-quantum vortex street' is observed in the other component. Other patterns of vortex shedding, such as oblique vortex dipoles, V-shaped vortex pairs, irregular turbulence, and combined modes of various wakes, can also be found. The ratio of inter-vortex spacing in one row to the distance between vortex rows is approximately 0.18, which is less than the stability condition 0.28 of classical fluid. The drag force acting on the obstacle potential is simulated. The parametric regions of Kármán vortex street and other vortex patterns are calculated. The range of Kármán vortex street is surrounded by the region of combined modes. In addition, spin–orbit coupling disrupts the symmetry of the system and the gain-loss affects the local particle distribution of the system, which leads to the local symmetry breaking of the system, and finally influences the stability of the Kármán vortex street. Finally, we propose an experimental protocol to realize the Kármán vortex street in a system. [ABSTRACT FROM AUTHOR]

We numerically and theoretically investigated the elliptic and vortex solitons, and their dynamical stabilities in a magnetized dusty plasma. By using the Petviashvili method, a type of completely localized solitons, which are also confirmed analytically, is found numerically. Numerical results indicate that the amplitude is proportional to its velocity and inverse proportional to the nonlinear interaction strength. The linear stability analysis shows that these solitons are always linearly stable, which agrees well with the nonlinear dynamic evolution. Finally, we find that both elastic and inelastic collisions exist when two localized solitons collide. It is an elastic one when the collision occurs between a localized soliton and a stable line soliton. However, a series of localized solitons will be excited if a localized soliton and an unstable line soliton collide, suggesting that inelastic collisions also exist. This finding may be helpful to understand the nonlinear phenomena in magnetized dusty plasma. [ABSTRACT FROM AUTHOR]

Propagation characteristics of obliquely incident terahertz waves in high-temperature magnetized plasma are studied by the scattering matrix method (SMM) and Wentzel–Kramers–Brillouin (WKB) method. Three cases of electron density distribution (uniform, double exponential, and Epstein distributions) are considered. Numerical simulation exhibits that the SMM can give out the nearly same results with the WKB method, which indicates that these two methods work very well for solving this problem. Through the analysis of the incident angle, we found that as the incident angle increases, it is not conducive to the transmission of left-handed circularly polarized (LCP) waves and right-handed circularly polarized (RCP) waves. When the incident angle increases to a certain value, the phenomenon of “total reflection” will appear. We also systematically calculated the influence of physical parameters such as electron density, collision frequency, plasma thickness, magnetic field strength, and electron temperature on the transmission characteristics. These theoretical results are helpful to alleviate “blackout” problem and improve communication quality. [ABSTRACT FROM AUTHOR]

The transmission characteristics of terahertz waves propagating in high-temperature magnetized inhomogeneous plasma are theoretically analyzed. The influence of physical parameters, such as the electron density, collision frequency, plasma thickness, magnetic field strength, electron temperature, and so on, on the transmission properties is considered systematically. Numerical results show that these parameters will affect the propagation characteristics of terahertz waves travelling in plasma. Especially, when the electron temperature of the plasma or the magnetic field is adjusted to an appropriate value, a sharp transmissivity peak (absorptivity valley) will be produced in the stop band. As the intensity of the magnetic field increases, the corresponding frequency of the transmissivity peak (absorptivity valley) will gradually shift to higher frequencies. The peak (valley) value will gradually increase as the electron temperature increases. These theoretical results may be used to effectively alleviate the "blackout problem". [ABSTRACT FROM AUTHOR]

The dynamical and energetic instabilities of the F = 2 spinor Bose–Einstein condensates in an optical lattice are investigated theoretically and numerically. By analyzing the dynamical response of different carrier waves to an additional linear perturbation, we obtain the instability criteria for the ferromagnetic, uniaxial nematic, biaxial nematic and cyclic states, respectively. When an external magnetic field is taken into account, we find that the linear or quadratic Zeeman effects obviously affect the dynamical instability properties of uniaxial nematic, biaxial nematic and cyclic states, but not for the ferromagnetic one. In particular, it is found that the faster moving F = 2 spinor BEC has a larger energetic instability region than lower one in all the four states. In addition, it is seen that for most states there probably exists a critical value k c > 0 , for which k > k c causes the energetic instability to arise under appreciative parameters. [ABSTRACT FROM AUTHOR]

The Homotopy analysis method (HAM) is adopted to find the approximate analytical solutions of the Gross- Pitaevskii equation, a nonlinear Schrodinger equation is used in simulation of Bose-Einstein condensates trapped in a harmonic potential. Comparisons between the analytical solutions and the numerical solutions have been made. The results indicate that they fit very well with each other when the atomic interaction is weak. [ABSTRACT FROM AUTHOR]

We try to find the analytical solutions to the time-independent Gross-Pitaevskii equation, a nonlinear Schrödinger equation used in the simulation of Bose-Einstein condensates trapped in a harmonic potential. Both the homotopy analysis method and the Galerkin spectral method are applied. We investigate the one-dimensional case and obtain the approximate analytical solutions successfully. Comparison between the analytical solutions and the numerical solutions has been made. The results indicate that they agree very well with each other when the atomic interaction is not too strong. [ABSTRACT FROM AUTHOR]

Damping solitary wave in dusty plasma is studied by considering the collision effect between dust grains and ions. It can be described by a KdV type equation in which a damping term of φ2 exist. It is found that both the amplitude and propagation velocity of the solitary wave decrease with time exponentially. Our results are compared with another KdV type equation with the damping term of φ. It is noted that the damping rate of the KdV type equation with the damping term of φ2 is larger than that with the term of φ. It is found that the damping rate is proportional to the collision frequency between dust grains and ions. [ABSTRACT FROM AUTHOR]

Abstract: According to the risks and risk control target in energy performance contracting (EPC), this paper has designed the risk control measure set. On the basis, a risk control model is put forward, including the risk evaluation, risk control cost, risk loss. Then, a multi-objective ant colony algorithm, based on Pareto theory, is used to solve the model. A series of Pareto optimal solutions are got by example. The result shows that the solutions have the better diversity and convergence. At the same time, the model can find the best combination of various risk control measures in EPC, which can provide direct evidence for the company of EPC. [Copyright &y& Elsevier]

By employing the quantum hydrodynamic model for electron-ion-dust plasma, we derive a dispersion relation of the quantum dusty plasma. The effects of the dust size distribution on the dispersion relation in a cold quantum dusty plasma are studied. Both analytical and numerical results are given to compare the differences between the dusty plasma by considering the dust size distribution and the mono-sized dusty plasma. It is shown that many system parameters can significantly influence the dispersion relation of the quantum dusty plasma. [ABSTRACT FROM AUTHOR]

The collision between two ion-acoustic solitary waves with arbitrary colliding angle θ in an unmagnetized, ultracold quantum three-component e-p-i plasma has been investigated. By using the extended Poincaré-Lighthill-Kuo (PLK) perturbation method, we obtain the KdV equations and the analytical phase shifts after the collision of two solitary waves in this three-component plasma. The effects of the quantum parameter H, the ratio of Fermi positron temperature to Fermi electron temperature σ, the ratio of Fermi positron number density to Fermi electron number density μ, and the ratio of Fermi ion temperature to Fermi electron temperature ρ on the phase shifts are studied. It is found that these parameters can significantly influence the phase shifts of the solitons. [ABSTRACT FROM AUTHOR]

As is well known, Korteweg–de Vries equation is a typical one which has planar solitary waves. By considering the higher-dimensional nonlinear waves, we studied a Kadomtsev–Petviashvili (KP) equation and found some interesting results which explain experimental results well enough. Two same amplitude soliton solution of KP equation explain resonance phenomena reported by some experiments. Two arbitrary amplitude soliton solution of KP equation is also obtained in this Letter, which can also results in resonance phenomena. The phase shift after interaction between two soliton are obtained theoretically in this Letter. It is in agreement with experimental results. [Copyright &y& Elsevier]

The magnitude of reflection and transmission at N arterial bifurcations are given. It is known that the maximum reflection will take place when the radii of all the artery bifurcations are same. The inhomogeneity of the artery will change the amplitude of the blood pulse wave which is in good agreement with the numerical results or the experiments. [Copyright &y& Elsevier]

The damping solitary wave in dusty plasma is studied by considering the collision effect between dust grains and ions. It can be described by a KdV type equation in which a damping term of φ 2 exists. We address the issues raised in the comment that the KdV-type equation obtained in the work is not correct in the paper [Phys. Plasmas 19, 103705 (2012)]. In this reply, we point out that there are some misprints which do not affect the derivation of the damping KdV equation but affect the coefficients of the damping KdV equation. The main results are the approximated analytical solution of the damping KdV equation, so the misprints affect the quantitative results but not the qualitative results. [ABSTRACT FROM AUTHOR]

According to the comments of Akbari-Moghanjoughi that the electron-positron-ion(e-p-i) plasmas parameters σ representing the ratio of the positron to electron Fermi-temperature and p standing for the positron to electron number-density ratio are related by the equation of p = σ 3/2. Based on this conclusion, we have replaced the Figs. 1-6 (Ref. 1) in the present paper. [ABSTRACT FROM AUTHOR]

By considering the ionization and recombination of the ions, as well as the collision between ions and dust grains, we have studied the damping solitary wave solution in a dusty plasma. In this paper, we find that the damping rate of the solitary wave increases as both the mass and the density of the dust grains increase. However, it decreases as the charge of the dust grain increases. [ABSTRACT FROM AUTHOR]

Abstract: Investigations for a dusty plasma with many different dust grain species are adopted, which varies self-consistently with the system parameters. Two cases have been studied. One is that the dust size distribution is given by Gaussian distribution. The other is that there is only one kind of dust grains (mono-sized dusty plasma) whose size is the average one of Gaussian distribution. The comparisons between them have been made and it is found that the linear phase velocity is different. [Copyright &y& Elsevier]

We consider a two-component Bose–Einstein condensate, which consists of both dipolar and scalar bosonic atoms, in a confinement that is composed of a harmonic oscillator and an underlying optical lattice set rotation. When the dipoles are polarized along the symmetry axis of the harmonic potential, the ground-state density distributions of such a system are investigated as a function of the relative strength between the dipolar and contact interactions, and of the rotation frequency. Our results show that the number of vortices and its related vortex structures of such a system depend strongly on such system parameters. The special two-component system considered here opens up alternate ways for exploring the rich physics of dipolar quantum gases. [ABSTRACT FROM AUTHOR]