Catálogo de publicaciones - revistas

<jats:p>The Schamel–Korteweg–de Vries equation is investigated by the approach of dynamics. The existences of solitary wave including <jats:italic>ω</jats:italic>-shape solitary wave and periodic wave are proved via investigating the dynamical behaviors with phase space analyses. The sufficient conditions to guarantee the existences of the above solutions in different regions of the parametric space are given. All possible exact explicit parametric representations of the waves are also presented. Along with the details of the analyses, the analytical results are numerically simulated lastly.</jats:p>

<jats:p>We investigate the problem of <jats:italic>ℋ</jats:italic> <jats:sub>∞</jats:sub> state estimation for discrete-time Markov jump neural networks. The transition probabilities of the Markov chain are assumed to be piecewise time-varying, and the persistent dwell-time switching rule, as a more general switching rule, is adopted to describe this variation characteristic. Afterwards, based on the classical Lyapunov stability theory, a Lyapunov function is established, in which the information about the Markov jump feature of the system mode and the persistent dwell-time switching of the transition probabilities is considered simultaneously. Furthermore, via using the stochastic analysis method and some advanced matrix transformation techniques, some sufficient conditions are obtained such that the estimation error system is mean-square exponentially stable with an <jats:italic>ℋ</jats:italic> <jats:sub>∞</jats:sub> performance level, from which the specific form of the estimator can be obtained. Finally, the rationality and effectiveness of the obtained results are verified by a numerical example.</jats:p>

<jats:p>We use the generalized Wootters formula, the positive partial transpose (PPT) criterion and the matched entanglement witness, to detect entanglement of three-qubit GHZ and W superposition state and its decayed states. It shows that the results of the generalized Wootters formula in the part near the W state are tight. In the other parts, the PPT criterion is superior to the generalized Wootters formula. Furthermore, we investigate the relationship between entanglement and coherence.</jats:p>

<jats:p>Shortcut to adiabaticity (STA) is a speedway to produce the same final state that would result in an adiabatic, infinitely slow process. Two typical techniques to engineer STA are developed by either introducing auxiliary counterdiabatic fields or finding new Hamiltonians that own dynamical invariants to constraint the system into the adiabatic paths. In this paper, an efficient method is introduced to naturally cover the above two techniques with a unified Lie algebraic framework and neatly remove the design difficulties and loose assumptions in the two techniques. A general STA scheme for different potential expansions concisely achieves with the aid of squeezing transformations.</jats:p>

<jats:p>This paper proposes a three-dimensional (3D) controlled quantum teleportation scheme for an unknown single-qutrit state. The scheme is first introduced in an ideal environment, and its detailed implementation is described via the transformation of the quantum system. Four types of 3D-Pauli-like noise corresponding to Weyl operators are created by Kraus operators: trit-flip, t-phase-flip, trit-phase-flip, and t-depolarizing. Then, this scheme is analyzed in terms of four types of noisy channel with memory. For each type of noise, the average fidelity is calculated as a function of memory and noise parameters, which is afterwards compared with classical fidelity. The results demonstrate that for trit-flip and t-depolarizing noises, memory will increase the average fidelity regardless of the noise parameter. However, for t-phase-flip and trit-phase-flip noises, memory may become ineffective in increasing the average fidelity above a certain noise threshold.</jats:p>

<jats:p>We study the stabilization properties of dipolar Bose–Einstein condensate in a deep one-dimensional optical lattice with an additional external parametrically modulated harmonic trap potential. Through both analytical and numerical methods, we solve a dimensionless nonlocal nonlinear discrete Gross–Pitaevskii equation with both the short-range contact interaction and the long-range dipole–dipole interaction. It is shown that, the stability of dipolar condensate in modulated deep optical lattice can be controled by coupled effects of the contact interaction, the dipolar interaction and the external modulation. The system can be stabilized when the dipolar interaction, the contact interaction, the average strength of potential and the ratio of amplitude to frequency of the modulation satisfy a critical condition. In addition, the breather state, the diffused state and the attractive-interaction-induced-trapped state are predicted. The dipolar interaction and the external modulation of the lattice play important roles in stabilizing the condensate.</jats:p>

<jats:p>This paper presents intensive investigation of dynamics of high frequency nonlinear modulated excitations in a damped bimodal lattice. The effects of the dissipation are considered through a linear dissipation coefficient whose evolution in terms of the carrier wave frequency is checked. There appears that the dissipation coefficient increases with the carrier wave frequency. In the linear limit and for high frequency waves, study of the asymptotic behavior of plane waves reveals the existence of two additional regions in the dispersion curve where the modulational phenomenon is observed compared to the lossless line. Based on the multiple scales method exploited in the continuum approximation using an appropriate decoupling ansatz for the voltage of the two different cells, it appears that the motion of modulated waves is described by a dissipative complex Ginzburg–Landau equation instead of a Korteweg–de Vries equation. We also show that this amplitude wave equation admits envelope and hole solitons in the high frequency mode. From basic sources, we design a programmable electronic generator of complex signals with desired characteristics, which delivers signals exploited as input waves for all our numerical simulations. These simulations are performed in the LTspice software that uses realistic components and give the results that corroborate perfectly our analytical predictions.</jats:p>

<jats:p>Weak value amplification has shown its superiority in measurement of small physical effects. Here we introduce a signal-recycled weak-value-based velocity measurement strategy to decrease the attenuation of detected photons during the post-selection. Like the power-recycled scheme, we can improve the number of detected photons and signal-to-noise ratio of velocity by forming a cavity. However, optimal improvements of number of detected photons and signal-to-noise ratio cannot be obtained simultaneously in our signal-recycled scheme owing to the walk-off effect. Furthermore, we find that the reflected light is relatively strong compared with the power-recycled scheme, which may increase the collection-detection efficiency in prospective relevant experiment.</jats:p>

<jats:p>The shielding property of cylinder with circular, square, and equilateral triangle holes was investigated by finite element analysis (FEA). The hole area (<jats:italic>S</jats:italic> <jats:sub>hole</jats:sub>) plays an important role in magnetic circuit on the surface of cylinder. When <jats:italic>S</jats:italic> <jats:sub>hole</jats:sub> is less than the critical area (<jats:italic>S</jats:italic> <jats:sub>H</jats:sub>), cylinder with three shapes of holes obtained the same remanent magnetization inside, indicating that the shielding property is unaffected by the shape of the hole. Hence, high-permeability material is the major path of the magnetic field. On the condition of <jats:italic>S</jats:italic> <jats:sub>hole</jats:sub> &gt; <jats:italic>S</jats:italic> <jats:sub>H</jats:sub>, the sequence of the shielding property is equilateral triangle &gt; square &gt; circular, resulting from magnetoresistance of leakage flux in air dielectric. Besides, the anisotropy of shielding property caused by hole structural differences of the cylinder is evaluated. We find that a good shielding effectiveness is gained in the radial direction, compared with the axis direction. This research focuses on providing a theoretical support for the design of magnetic shield and improvement on the magnetic shielding ability.</jats:p>

<jats:p>We report the production of <jats:sup>39</jats:sup>K and <jats:sup>87</jats:sup>Rb Bose–Einstein condensates (BECs) in the lowest hyperfine states | <jats:italic>F</jats:italic> = 1,<jats:italic>m<jats:sub>F</jats:sub> </jats:italic> = 1 〉 simultaneously. We collect atoms in bright/dark magneto-optical traps (MOTs) of <jats:sup>39</jats:sup>K/<jats:sup>87</jats:sup>Rb to overcome the light-assisted losses of <jats:sup>39</jats:sup>K atoms. Gray molasses cooling on the D1 line of the <jats:sup>39</jats:sup>K is used to effectively increase the phase density, which improves the loading efficiency of <jats:sup>39</jats:sup>K into the quadrupole magnetic trap. Simultaneously, the normal molasses is employed for <jats:sup>87</jats:sup>Rb. After the microwave evaporation cooling on <jats:sup>87</jats:sup>Rb in the optically plugged magnetic trap, the atoms mixture is transferred to a crossed optical dipole trap, where the collisional properties of the two species in different combinations of the hyperfine states are studied. The dual species BECs of <jats:sup>39</jats:sup>K and <jats:sup>87</jats:sup>Rb are obtained by further evaporative cooling in an optical dipole trap at a magnetic field of 372.6 G with the background repulsive interspecies scattering length <jats:italic>a</jats:italic> <jats:sub>KRb</jats:sub> = 34 <jats:italic>a</jats:italic> <jats:sub>0</jats:sub> (<jats:italic>a</jats:italic> <jats:sub>0</jats:sub> is the Bohr radius) and the intraspecies scattering length <jats:italic>a</jats:italic> <jats:sub>K</jats:sub> = 20.05<jats:italic>a</jats:italic> <jats:sub>0</jats:sub>.</jats:p>