International Journal of Modern Physics B

The influences of temperature and cyclotron frequency of a magnetic field on the ground state energy and mean number of phonons (MNP) of strong-coupling magnetopolarons in an asymmetric Gaussian potential quantum well(AGPQW) are researched by employing the linear-combination operator method and the unitary transformation. It was demonstrated through the numerical calculations that the ground state energy and the MNP increase with higher magnetic field cyclotron frequencies and temperature. In addition, increasing of the barrier of asymmetric Gaussian potential (AGP) causes the ground state energy to decrease while increasing the MNP of magnetopolarons.

In this work, the solutions of the real coupled Kadomtsev–Petviashvili equations (KPEs) are obtained and they are used to find the ones of the complex system. To this end, the extension theorem is used. The formation of rogue wave (RW) is shown to occur via inelastic collisions of lines-lump solitons and periodic waves and also of two elliptic waves. The quadratic invariant is used to show the phase portrait and bifurcation through the contour plot. Further, the conservation laws (CLs) are constructed by means of new conservation theorem by finding the governing system of equation. The results are given, work consolidated from a previous work, by the first two authors, for suggesting a mechanism for the formation of RW when the complex Korteweg–de Vries equation was studied. Based on the exact solutions found here, numerical computations are carried out and they are represented graphically. Finally, the unified method (UM) can be applied to solve a variety of partial differential equations in science and engineering.

Ultrasonic velocity measurements could be performed on a good quality single crystal of ${\mathrm{\text{Lu}}}_5{\mathrm{\text{Ir}}}_4{\mathrm{\text{Si}}}_{10}$ around its transition around 80 K. The behavior of the stiffness components demonstrates a first-order transition. The temperature dependence of the longitudinal elastic stiffness components $C_{11}$ and $C_{33}$ can be analyzed by the classical Landau theory and assuming a stricter coupling between the strain and the order parameter. A theoretical approach and experimental results are discussed.

In this paper, a method is proposed to prepare rock-like materials with different thicknesses of hidden joints. Then, permeability and porosity of the self-prepared jointed specimens under different pore pressures during confining pressure loading and unloading are measured. The experimental results indicate that the gas permeability of the jointed specimens gradually decreases with the rise of pore pressure due to the existence of Klinkenberg effect, and Klinkenberg effect gradually decreases with the rise of hidden joint thickness. As the main seepage channels, hidden joints govern the seepage characteristics, and due to the existence of hidden joints, the intrinsic permeability is improved significantly. Besides, due to the existence of hidden joints, the intrinsic permeability and porosity are more sensitive to confining pressure loading than that of the intact specimen, and the sensitivity increases with the rise of hidden joint thickness. During confining pressure loading, there is a permanent deformation of the hidden joints and pores in the specimens, which results in both the intrinsic permeability and porosity being always lower than those in the loading process. Meanwhile, the permanent deformation rises with the increases of hidden joint thickness, which leads to the increases of gap of intrinsic permeability and porosity under loading and unloading processes. Additionally, after comparison of the fitting results, the sub-cubic law can reflect the relationship between flow rate and the thickness of non-persistent joints better than the cubic law.

The morphologies of diblock copolymers self-assembled under selected solvent have been investigated systematically using a simulated annealing method. Various categories of internal morphologies are observed. The morphology transform can be modulated by three important factors: softness of confinement, volume fraction of A/B monomers ($f_{\mathrm{\text{A}}}$ and $f_{\mathrm{\text{B}}}$) and selectivity of solvent. With increase in $f_{\mathrm{\text{A}}}$, the selectivity of solvent can determine the type and number of cores. The softness of confinement can greatly influence the shape of copolymer which prefers to be sphere or nonsphere. Stacked lamella morphology is an efficient method to reduce the contact number between A-B blocks in softer confinement. Core–shell morphologies usually have large curly degree with small end-to-end distance of AB complex chain. The nucleation condition is that the ratio of end-to-end distance of AB complex chain to the length of whole chain is lower than 0.28. The simulation results can provide theoretical guidance for experiment in synthesis of nanoparticles.

Iron silicides provide extensive applications in functional device and earth science. Very little is known about these alloys at high pressures and temperatures. Here, combining swarm-intelligence-based structure prediction methodology and quasi-harmonic approximation (QHA), we investigate Fe-Si compounds at pressures of up to 500 GPa. Evolutionary simulations correctly find the known B20-FeSi structure and some other experimentally observed compounds at atmospheric pressure and finite temperature. It is shown that among the possible iron silicides, only B2-FeSi is thermodynamically stable at high pressures, and the increasing temperature tends to stabilize B2-FeSi compound rather than other iron silicides.

The k9 glass emerges as the promising host for the waveguide formation, owing to its unique optical properties. Ion implantation is a powerful technique for the fabrication of optical waveguides. In this work, the 400-keV proton implantation at a dose of $8.0\times 10^{16}$ ${\mathrm{\text{ions/cm}}}^2$ was performed on the k9 glass to manufacture optical waveguide. Continuous annealing treatment at intervals of $50^{\circ }\mathrm{\text{C}}$ was used to enhance the guiding performances of the waveguide. The dark-mode spectrum and the refractive index profile of the waveguide were obtained by a prism coupling system and a reflectivity calculation method, respectively. The near-filed intensity distribution was measured by an end-face coupling equipment. The results suggest that the light field can be confined within the waveguide layer.

Quantum disentanglement refers to the transformation of entangled quantum system into disentangled system via some physical processes. In this paper, we search for quantum disentangling operator for the mesoscopic two-loop $LC$ circuit with mutual inductance $m$. It is this mutual inductance that causes quantum entanglement. By virtue of the method of integration within ordered product (IWOP) of operators, we find the disentangling operator and deduce the energy level (characteristic frequency). The quantum noise expression of squeezed vacuum state is also derived based on which we see that the large number of quantum entanglement engendered by the mutual inductance is, the more quantum noise produces in the mesoscopic circuit.

Diffusion bonding is an effective method for joining dissimilar materials. In this study, dissimilar metals of MA956 steel and tungsten (W) were diffusion bonded with Ni/Nb composite interlayer. The experiments were carried out at $1050^{\circ }\mathrm{\text{C}}$, 20 MPa for 20 min in vacuum by spark plasma sintering (SPS) technique. The microstructure and mechanical properties of the bonded joints were evaluated. SEM images and the results of elementary composition indicate that no intermetallics formed at Ni/MA956 steel and Nb/W interfaces, but ${\mathrm{\text{Ni}}}_6{\mathrm{\text{Nb}}}_7$ and ${\mathrm{\text{Ni}}}_3\mathrm{\text{Nb}}$ formed at the Nb/Ni interface. Compared with the directly bonded joint between W and MA956 steel, the average shear strength of the joint with Nb/Ni composite interlayer significantly increased to 270 MPa. Although the result of joint residual stresses simulation shows that the maximum residual stress was near the W substrate, the joints with composite interlayer in shear experiments fractured at Nb/Ni interface. The hardness changes along joint interfaces indicate the formation of intermetallic compounds and solid solution phases in the diffusion layers.

Quantum state sharing plays an important role in both transmitting and protecting a quantum secret information. However, in a realistic situation, quantum communication protocol is inevitably affected by the decoherence and noise induced by the interaction between quantum system and environment, which often destroys quantum resource, such as degrading entangled state that is often used as the key resource of quantum communication. In this paper, we intend to investigate the influence of amplitude damping (AD) decoherence on multi-party qutrit-state sharing (MQSS) scheme. We firstly construct the noisy model of MQSS, and then analyze the effect of decoherence on the MQSS. In addition, the relation of variations between MQSS performance and quantum coherence is illustrated. Furthermore, we propose a partial measurement to enhance the performance of the MQSS under noisy environment.

Relationship between matter and energy transport has always been one of the key issues that researchers have been searching for in statistical physics and complexity science. In many transport phenomena, the active transport with zero or even no external force in life activities has attracted extensive attention of scholars. As a special kind of active particles, active Brownian particles have received the attention of physicists and biophysicists. These active particles are natural or artificially designed particles, whose scale is in the order of micrometer or nanometer. Different from the traditional passive Brownian particles driven by the equilibrium heat wave generated by the random collision of the surrounding fluid molecules, active Brownian particles can extract energy from their own environment to drive their own motion. Here, directional transport process of active particles in the two-dimensional asymmetric ratchet potential field is analyzed. Both the overdamped medium and the critically damped one are emphasized. Langevin equations with inertia term are introduced to describe the impacts of the self-driven force, friction coefficient, etc. on the directional motion. Then, the average particle speed is found. Thereafter, the relationships between the speed and critical parameters like self-driven force, friction coefficient, etc. are obtained. Two different dynamical domination mechanisms are found, which are expressed as the random collision domination and the self-driven force domination, respectively. Furthermore, the random collision domination is found to correspond to the much higher peak of the two-dimensional asymmetric Brownian rachet potential field, while the self-driven force domination is found to correspond to the much lower peak of the introduced potential. The study will be helpful for discovering the stochastic thermodynamics mechanisms in nonlinear dynamics and nonlinear properties of such multibody interaction system in statistical physics and complex system science.

We design and build an acoustic invisible medium (AIM) based on first principles. Isotropic, inhomogeneous mass density and bulk modulus profiles of the AIM are derived from scattering-free conditions. Acoustic invisibility is illustrated by two types of examples: the AIM under plane-wave incidence and point sound sources. It is found that an AIM of arbitrary shape is invisible to plane waves of any incident angle. The invisibility of the AIM holds for any sound source sitting anywhere except for in the AIM region. Acoustic field distributions show that the acoustic wave enters the AIM from one side and recovers its initial shape at the other side. The designed AIMs are numerically verified by the finite element method, and are highly consistent with theoretical results. This work offers an alternative strategy to achieve a scattering-free AIM and could be extendable to the three-dimensional cases.

Ion source provides sample ions for FAIMS. The key technology is ionization method. Efficient ionization of analytes is the core technology for data acquisition in high quality FAIMS systems. In order to long-distance detect and analyze harmful and toxic substances such as explosives, drugs, chemical reagents and environmental pollutants in an open environment, without pretreatment, real-time and on-line, the ion source control and its technical device using excessive electric field were designed and developed. The disadvantages of high flow rate of APCI and low flow rate of ESI are integrated, based on the chemical analysis principle of FAIMS, an experimental platform of ionization technology based on excessive electric field is proposed and designed, which mainly includes: ion focusing system, flat-panel migration zone with focusing structure, sample integration, etc. The experimental results show that the ion source based on excessive electric field can be widely used in biochemical weapon warning, drug tablet detection, environmental monitoring, food and drug detection and clinical medicine, and the detection limit can reach 0.1 ppm.