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The low dimensional inorganic–organic (IO) hybrid semiconductors become a fascinating subject of interest due to their unique crystal structural packing and tunable optical exciton emission features. These naturally self-assembled 2D IO hybrid semiconductors form multiple quantum wells (MQWs) like structure due to the quantum widths of both organic moiety and inorganic network , enabling them to show stable room temperature Mott-type excitons with large exciton binding energy. A systematic co-existence of two kinds of excitons observable from one-(ħω ≥ Eg) and two-photon (2ħω ≥ Eg) excitations is studied to probe into deeper details of sensitive structural changes in the IO-hybrids thin film and single crystals.

Perfect state transfer and fractional revival can be used to move information between pairs of vertices in a quantum network. While perfect state transfer has received a lot of attention, fractional revival is newer and less studied. One problem is to determine the differences between perfect state transfer and fractional revival. If perfect state transfer occurs between two vertices in a graph, the vertices must be cospectral. Further if there is perfect state transfer between vertices $a$ and $b$ in a graph, there cannot be perfect state transfer from $a$ to any other vertex. No examples of unweighted graphs with fractional revival between non-cospectral vertices were known; here we give an infinite family of such graphs. No examples of unweighted graphs where the pairs involved in fractional revival overlapped were known; we give examples of such graphs as well.

Ramping a physical parameter is one of the most common experimental protocols in studying a quantum system, and ramping dynamics has been widely used in preparing a quantum state and probing physical properties. Here, we present a novel method of probing quantum many-body correlation by ramping dynamics. We ramp a Hamiltonian parameter to the same target value from different initial values and with different velocities, and we show that the first-order correction on the finite ramping velocity is universal and path-independent, revealing a novel quantum many-body correlation function of the equilibrium phases at the target values. We term this method as the non-adiabatic linear response since this is the leading order correction beyond the adiabatic limit. We demonstrate this method experimentally by studying the Bose-Hubbard model with ultracold atoms in three-dimensional optical lattices. Unlike the conventional linear response that reveals whether the quasi-particle dispersion of a quantum phase is gapped or gapless, this probe is more sensitive to whether the quasi-particle lifetime is long enough such that the quantum phase possesses a well-defined quasi-particle description. In the Bose-Hubbard model, this non-adiabatic linear response is significant in the quantum critical regime where well-defined quasi-particles are absent. And in contrast, this response is vanishingly small in both superfluid and Mott insulators which possess well-defined quasi-particles. Because our proposal uses the most common experimental protocol, we envision that our method can find broad applications in probing various quantum systems., Comment: 7 pages for main text. Science Bulletin (2022)

Journal of magnesium and alloys 10(11), 3281-3287 (2022). doi:10.1016/j.jma.2021.08.008, Published by Elsevier, Amsterdam [u.a.]

Introduction The Gross-Pitaevskii equation is a class of the nonlinear Schrodinger equation, whose exact solution, especially soliton solution, is proposed for understanding and studying Bose-Einstein condensate and some nonlinear phenomena occurring in the intersection field of Bose-Einstein condensate with some other fields. It is an important subject to investigate their exact solutions. Objectives We give multi-soliton of a two-dimensional Gross-Pitaevskii system which contains the time-varying trapping potential with a few interactions of multi-soliton. Through analytical and graphical analysis, we obtain one-, two- and three-soliton which are affected by the strength of atomic interaction. The asymptotic expression of two-soliton embodies the properties of solitons. We can give some interactions of solitons of different structures including parabolic soliton, line-soliton and dromion-like structure. Methods By constructing an appropriate Hirota bilinear form, the multi-soliton solution of the system is obtained. The soliton elastic interaction is analyzed via asymptotic analysis. Results The results in this paper theoretically provide the analytical bright soliton solution in the two-dimensional Bose-Einstein condensation model and their interesting interaction. To our best knowledge, the discussion and results in this work are new and important in different fields. The results enrich the existing nonlinear phenomena of the Gross-Pitaevskii model in Bose-Einstein condensation, and prove that the Hirota bilinear method and asymptotic analysis method are powerful and effective techniques in physical sciences and engineering for analyzing nonlinear mathematical-physical equations and their solutions. These provide a valuable basis and reference for the controllability of bright soliton phenomenon in experiments for high-dimensional Bose-Einstein condensation.

International audience; Finite element simulation modeling permits to predict hydrogen concentration for various initial boundary-values problems, but the results depend on the underlying transport mechanisms accounted for. Trapping process is a key factor in the apparent hydrogen diffusion, and the case of mobile traps as dislocations needs modification of the hydrogen transport equation usually considered in the literature. An extension of this model is proposed where hydrogen dragging by mobile traps is modeled by reaction-diffusion equations, involving trapping and detrapping kinetic, and is applied for evolving trap density with plastic strain. The consequences of trapped hydrogen mobility on diffusive hydrogen repartition in a reference Small Scale Yielding configuration are focused on, especially in term of acceleration of hydrogen transport. The potentiality of the model is illustrated by the modeling of the trapped hydrogen breakaway from fast moving dislocations.

The fault type of GIS during running is related to the decomposition of the insulating gas SF6. In this paper, the adsorption behavior of three representative gases (SO2, SOF2, and SO2F2) decomposed by SF6 under unfavorable conditions at high temperature on the surface of Sc-doped WSe2 monolayers was discussed based on density functional theory. Adsorption systems of three target gases on Sc-WSe2 were developed, and the structural parameters, density of states and frontier molecular orbitals were calculated. The results show that the adsorption performance of target gases on Sc-WSe2 is better than that on intrinsic WSe2, indicating that the effectiveness of utilizing Sc atoms for modification. The strong interaction between WSe2 monolayers embedded with Sc atoms and gases confirmed the stability of the system in complex environments. Our findings are of great significance in the construction of atomically modified WSe2 gas sensors for detecting SF6 decomposition gases.

The violent fluid motion in a partially filled vessel is called sloshing. Resonance occurs when the natural frequency of the fluid oscillation approaches that of its container. This result may lead to structural failure. In this study, a Smoothed Particle Hydrodynamics (SPH) model is established to investigate the sloshing motion in a shallow water reservoir. Sloshing in a submerged obstacle, cylinder array, rectangular and wall-inclined topography is considered. In terms of results, the cylinder array is more effective than the other models to reduce the impact force due to the sloshing wave in a rectangular tank. The results prove that the proposed SPH model is capable of simulating sloshing in the shallow water tank.

When the drawdown pressure amounts to a value below the dew point pressure, a minor droplet of condensate is shaped and accumulated in the close area of wellbore. As the accumulation happens, the saturation of the liquid will grow and a reduction in gas relative permeability will happen, therefore it will affect the productivity. Generally, condensate baking problem in gas wells is being deliberated and studied and numerous techniques have been suggested to solve the problem. The studying of condensate banking dynamics is essential to evaluate the productivity and behavior of the wells of the gas fields.

We examine the viability of cosmological solution(s) describing a unified picture of the dark side of the universe from a Bose-Einstein condensate (BEC) of light bosons. The energy density of the BEC, together with its quantum potential, can indeed account for such a unification, in the sense that the (dust-like) cold dark matter and the dark energy components emerge from the same source. In particular, the bulk of the dark energy can be attributed to the quantum potential, in the quantum corrected Raychaudhuri-Friedmann equation, when the `macroscopic' BEC wave-function is taken to be such that the corresponding probability density is construed as the energy density of the dusty fluid. However, there arises a purely quantum mechanical back-reaction effect, of even the visible baryons, on the effective dark energy and dark matter contents, which crucially determines the mass of the BEC. We determine the constraint on such a back-reaction, and hence on the BEC mass, from physical considerations, as well as estimate the same using recent observational data., 31 pages, 5 figures, 1 table

To improve the efficiency of automobile air conditioning and reduce the impact of non-uniform air velocity distributions caused by the front anti-collision beam on automobiles, we designed a new six-process condenser and tested it under different working conditions. A baffle was positioned to simulate the anti-collision beam during the experiment. We analyzed the condenser by itself and the system level performance of this newly designed condenser under three working conditions compared to a traditional four-process condenser. Condenser heat exchange capacity, condenser inlet pressure, system refrigerant flow rate, refrigerant flow resistance, thermal imaging of condenser outlet air, overall system cooling capacity, and coefficient of performance were compared. The coefficient of performance of the system with this new condenser improved by 8.5%, 7.8%, and 10.3% for the three tested working conditions.

The strength of drilling mud filter cakes is a parameter of practical relevance during well construction. This work simulates a ‘hole punch test’ experiment to determine filter cake yield stress. The discrete element model is used to predict the energy needed to push a plunger through the cake. The theoretical data is compared with experimental measurements for cakes with varying particle size and shape. The simulations and experiments both show an increase in yield stress and required energy with decreasing cake porosity and particle size. Adhesion due to liquid bridges was found to contribute significantly to cake strength. A scaling argument is established which indicates that the resistance to plunger motion comes from the particles sheared at the edge of the plunger.

We pose the problem of transferring a Bose-Einstein Condensate (BEC) from one side of a double-well potential to the other as an optimal control problem for determining the time-dependent form of the potential. We derive a reduced dynamical system using a Galerkin truncation onto a finite set of eigenfunctions and find that including three modes suffices to effectively control the full dynamics, described by the Gross-Pitaevskii model of BEC. The functional form of the control is reduced to finite dimensions by using another Galerkin-type method called the chopped random basis (CRAB) method, which is then optimized by a genetic algorithm called differential evolution (DE). Finally, we discuss the extent to which the reduction-based optimal control strategy can be refined by means of including more modes in the Galerkin reduction.

The heat transfer process in the condenser is often divided into superheated, two-phase and subcooled zone. But the three-zone model has discontinuities of the heat transfer coefficient between single phase and two-phase regions. This study applies a computational fluid dynamics (CFD) study on the two phase flow and the heat transfer characteristics in the condensing-superheated zone. The condensation process of R410A (Tsat=44.59 °C) in a horizontal pipe (Di=6.1 mm) is simulated by using VOF (volume of fluid) model. The formation and the development of the condensation film are detailed analyzed. The heat transfer mechanism in the condensing-superheated zone includes both the single-phase convection and the phase transition. The heat transfer coefficient in the superheated condensation area increases from the single-phase convection to the saturated condensation. Combined with the development of liquid film morphology, this study is helpful for understanding the flow and heat transfer mechanism in the condensing-superheated zone.

Determination and conceptualization of atomic structures of metallic glasses or amorphous alloys remain a grand challenge. Structural models proposed for bulk metallic glasses are still controversial owing to experimental difficulties in directly imaging the atom positions in three-dimensional structures. With the advanced atomic-resolution imaging, here we directly observed the atomic arrangements in atomically thin metallic glassy membranes obtained by vapor deposition. The atomic packing in the amorphous membrane is shown to have a fractal characteristic, with the fractal dimension depending on the atomic density. Locally, the atomic configuration for the metallic glass membrane is composed of many types of polygons with the bonding angles concentrated on 45°–55°. The fractal atomic structure is consistent with the analysis by the percolation theory, and may account for the enhanced relaxation dynamics and the easiness of glass transition as reported for the thin metallic glassy films or glassy surface.

This note presents selected measurements of W and Z boson production, carried out with the CMS experiment at the LHC, based on samples of events collected during 2015–2018 physics runs. W boson events were selected containing an isolated, energetic electron or muon, while Z boson events were selected containing a pair of isolated, energetic electrons or muons. Presented results include searches for rare decays of W bosons to pions.

Li4SiO4 crystal is a candidate material for tritium breeder material. Vacancy defects and He atoms will be produced in the crystal after neutron irradiation in fusion reactor. In previous research, we learned vacancy defects mainly include VO0, VO2+, and VLi0, meanwhile, He atoms are easy to migrate and aggregate in the crystal. In order to understand the relationship between vacancy defects and He atoms, we use density functional theory (DFT) to study the interaction mechanism between vacancy and He atom. The results show that the local stable sites of He atoms are related to the surrounding charge distribution. VO2+ and VLi0 can capture interstitial He atoms, and it is difficult to escape the vacancies, thereby increasing the nucleation center of He atoms. VO0 promotes the diffusion of He atoms in the interstitial space, which will cause small helium bubbles to merge more easily.

Two recent and prominent results in Higgs boson physics from the CMS experiment are presented. The major result is the first evidence for the Higgs boson decay to a pair of muons, and therefore for its coupling to second generation fermions, a milestone in establishing the Higgs boson properties. Also presented are new searches for the nonresonant production of Higgs boson pairs via gluon and weak boson fusion processes in final states with two bottom quarks and two photons, yielding most stringent constraints to date on these productions, and on the Higgs boson self-coupling.

We consider here the integer minimum cost network flow when some of the supplies are fractional. In the presence of fractional supplies it is impossible to satisfy the flow balance constraints, creating an imbalance. We present here a polynomial time algorithm for minimizing the total cost of flow and imbalance penalty. We also show that in the presence of a constraint that bounds the imbalance the problem is NP-hard, but efficiently solvable for a fixed number of fractional supplies.

We investigate the existence of ground state solutions of a Gross-Pitaevskii equation modeling the dynamics of pumped Bose Einstein condensates (BEC). The main interest in such BEC comes from its important nature as macroscopic quantum system, constituting an excellent alternative to the classical condensates which are hard to realize because of the very low temperature required. Nevertheless, the Gross Pitaevskii equation governing the new condensates presents some mathematical challenges due to the presence of the pumping and damping terms. Following a self-contained approach, we prove the existence of ground state solutions of this equation under suitable assumptions: This is equivalent to say that condensation occurs in these situations. We also solve the Cauchy problem of the nonlinear Schrodinger equation and prove some corresponding laws.

Since the realization of Bose-Einstein condensates (BECs) in optical potentials, intensive experimental and theoretical investigations have been carried out for matter-wave solitons, coherent structures, modulational instability (MI), and nonlinear excitation of BEC matter waves, making them objects of fundamental interest in the vast realm of nonlinear physics and soft condensed-matter physics. Ubiquitous models, which are relevant to the description of diverse nonlinear media are provided by the nonlinear Schrodinger (NLS), alias Gross-Pitaevskii (GP) equations. In many settings, nontrivial solitons and coherent structures, which do not exist or are unstable in free space, can be created or stabilized by means of various management techniques, which are represented by NLS and GP equations with spatiotemporal coefficients in front of linear or nonlinear terms. Developing this direction of research in various settings, efficient schemes of the spatiotemporal modulation of coefficients in the NLS/GP equations have been designed to engineer desirable robust nonlinear modes. This direction and related ones are the main topic of the present review. A broad and important theme is the creation and control of 1D solitons in BEC by means of combination of the temporal or spatial modulation of the nonlinearity strength and a time-varying trapping potential. An essential ramification of this topic is analytical and numerical analysis of MI of continuous-wave states, and control of the nonlinear development of MI. In addition to that, the review also includes some topics that do not directly include spatiotemporal modulation but address physically important phenomena which demonstrate similar soliton dynamics. These are soliton motion in binary BEC, three-component solitons in spinor BEC, and dynamics of two-component solitons under the action of spin-orbit coupling., This paper is accepted for publication at Physics Report

The minimal $U(1)_X$ extension of the Standard Model (SM) is a simple and well-motivated extension of the SM, which supplements the SM with the seesaw mechanism for naturally generating the light neutrino masses and offers various interesting phenomenologies. In the model, the $U(1)_X$ charge of each SM field is characterized by the $U(1)_X$ charge of the SM Higgs doublet with a free parameter $x_H$. Due to the $U(1)_X$ charge of the Higgs doublet, the Higgs boson has a trilinear coupling with the $Z$ boson and the $U(1)_X$ gauge boson ($Z^\prime$). With this coupling, a new process for the associated Higgs boson production with a $Z$ boson arises through a $Z^\prime$ boson in the $s$-channel at high energy colliders. In this paper, we calculate the associated Higgs boson production at high energy colliders and show interesting effects of the new $Z^\prime$ boson mediated process, which can be tested in the future., 19 Pages, 9 Figures

We consider Arrow’s and Wilson’s theorems as conditions on domains, as well as a third condition due to Malawski and Zhou (1994). We describe when domains satisfying each combination of these conditions exist.

Current ramp-up productions at manufacturing companies are characterized by a high quantity of unpredicted development efforts. These unpredicted development efforts result in not achieved ramp-up targets such as time-to-market or time-to-volume and in exceeded ramp-up budgets. The highly iterative product development offers the potential to reduce unpredicted development efforts due to the agile approach and the manufacturing of a high quantity of physical prototypes. In the following, agile ramp-up production as the combination of highly iterative product development and ramp-up production is presented as a potential solution approach to optimize and stabilize current ramp-up productions by reducing unpredicted development efforts.

As is well known in atomic optics, the nonadiabatic transitions induce the loss of atoms trapped in a magnetic well which seriously affects the formation of the Bose-Einstein condensates. Electrostatic traps have widespread applications in molecular optics. While, for most existing electrostatic traps, the electric field strength in the trap center is nearly zero which may cause the nonadiabatic transitions. Especially for a chip-based microtrap, ingenious design is need to overcome this problem. In the paper, we propose a novel electrostatic microtrap composed of four arc-shaped electrodes. The influences of the voltages and the geometrical parameters of the electrodes on the electric field strength as well as the height of the potential well are studied. The distributions of electrostatic field are numerically calculated. We firstly simulate the trajectory of one molecule in the processes of loading and trapping. After that, we simulate the movements of a large number of molecules using the method of Monte Carlo. Then we calculate the temperature of trapped cold molecules. After that, we analyze the impacts of voltages and the geometrical parameters on the efficiency of our microtrap. At last, we show that our scheme can evolve into electrostatic microtrap arrays which should be a powerful tool for a variety of basic research and applications.

We study solvability of the Diophantine equation \begin{equation*} \frac{n}{2^{n}}=\sum_{i=1}^{k}\frac{a_{i}}{2^{a_{i}}}, \end{equation*} in integers $n, k, a_{1},\ldots, a_{k}$ satisfying the conditions $k\geq 2$ and $a_{i}, Comment: 13 pages, to appear in the Journal of Number Theory

There is an immense effort in search for various types of Weyl semimetals, of which the most fundamental phase consists of the minimal number of i.e. two Weyl points, but is hard to engineer in solids. Here we demonstrate how such fundamental Weyl semimetal can be realized in a maneuverable optical Raman lattice, with which the three-dimensional (3D) spin-orbit (SO) coupling is synthesised for ultracold atoms. In addition, a new novel Weyl phase with coexisting Weyl nodal points and nodal ring is also predicted here, and is shown to be protected by nontrivial linking numbers. We further propose feasible techniques to precisely resolve 3D Weyl band topology through 2D equilibrium and dynamical measurements. This work leads to the first realization of the most fundamental Weyl semimetal band and the 3D SO coupling for ultracold quantum gases, which are respectively the significant issues in the condensed matter and ultracold atom physics., 6 pages + supplementary material

Optical lattices are known for their flexibility to emulate condensed matter physics and beyond. Based on an early theoretical proposal [Science Bulletin 65, 2080 (2020)], a recent experiment published by Wang et al. [Science 372, 271 (2021)] accomplishes the first experimental realization of topological band structure of the ideal Weyl semimetal in ultracold atomic matter, prompting fundamental interest in the context of gapless topological physics. With a neat design of 3D spin-orbit interaction, the experiment has probed the gapless band topology through spin texture imaging and quantum quench dynamics. This work has far reaching implications to topological effects and quantum anomaly in condensed matter and high energy physics., Comment: 4 pages, 2 figures, invited news & view short paper

The luminescence spectra for noble gases and their binary mixtures excited by Ar ions with energies up to 70 MeV were examined in the range of 200–980 nm. The emissions at the transitions of heteronuclear ionic molecules ArXe+, ArKr+, KrXe+ were studied for a gas-mixture, with a wide variation in the percentage composition. The noble gases atomic spectra are dominated by lines of (n + 1)p-(n + 1)s-transitions (2p-1s in Pashen’s notation); lines of d-(n + 1)p-transitions were also observed. The distribution of radiation over 2p-levels of noble gas atoms was also measured. The sharp predominance of the fraction of radiation from the levels 2p2 of Ar, 2p6 of Kr and 2p5 of Xe is partially explained by the relatively small values of the rate constants for the deactivation of these levels, by own atoms. The mechanisms of levels population under the excitation of noble gases by ionizing radiation are discussed.

In this paper we study the structure of positive vector solutions for nonlinear Schrodinger systems with 3 components when all interspecies interaction forces are positive and large while all intraspecies interaction forces are positive and fixed. We will show that the structure strongly depends on some relation of large interspecies interaction forces.

We review briefly the origin of gauge physics as well as their modern manifestations e.g. in Yang–Mills, Aharonov–Bohm, Aharonov–Casher, and the Berry–Pancharatnam effects. Yang–Mills has its origin in the high energy physics, and has since been widely studied in condensed matter and atomic physics. Recently research in spin–orbit coupling is increasingly being cast in the light of Yang–Mills, leading to new approaches in the study of quantum transport in nanoscale settings like the 2D-graphene and semiconductor nanostructures. It is important to note that this paper will not review non-Abelian physics in condensed matter systems like superfluid, Mott insulators, and atomic quantum gases. The main coverage of this paper would be the non-Abelian, Yang–Mills-inspired gauge physics in fields that straddle condensed matter and quantum spin transport – a technologically relevant field of research also known as the spintronics. Our perspectives are the force and phase physics and their connection with well-known spintronic and magnetic phenomena. The force physics of the spintronic gauge, e.g. the spin Hall, spin jitter motion, quantum spin Hall, and spin torque is discussed. The other important aspect of the gauge field, i.e. its phase physics would be discussed in the context of spin interference and the persistent spin helix.

Summary Moire superlattices have recently become excellent platforms for studying new properties of two-dimensional (2D) layered materials. With periodic moire patterns, moire superlattices can induce structural altering and band transformations, resulting in new phenomena including moire phonons, moire excitons, topological phase transition, unconventional superconductivity, or Mott insulation. With specific moire superlattices, bilayer or trilayer 2D materials (including heterostructures) can act as excellent models gathering interlayer interactions, intralayer features, band alignments, charge transport, and other effects (such as spin-orbit coupling and splitting) in a single system. This Review introduces the origin and the modulation of moire superlattices and summarizes several series of new properties discovered in 2D layered materials. We believe that moire superlattices mean new access to more structures, more properties, more physics, and more opportunities for both fundamental studies and applications of 2D materials.

A first principles calculation is carried out on a typical heavy fermion system-CeCu2Si2 by using a many-body method combing density functional theory (DFT) and dynamical mean-field theory (DMFT) along with the on-site Coulomb repulsion (represented by the Hubbard U parameter) for capturing the electronic correlation due to the incompletely filled Ce 4f orbitals. The results establish that the average occupation of Ce 4f electrons nf is about 1.02 (mainly 4f1 atomic configuration), close to the nominal occupation in pure Ce metal and in good agreement with the spectrum function in this work and the available experimental observations. The imaginary part of the impurity Green function indicates that the Ce 4f j = 5/2 and j = 7/2 states have metallic and insulating behavior, respectively. The dehybridization between the Ce 4f orbitals and ligand valence orbitals in the vicinity of the Fermi level is responsible for the localized 4f state and heavy fermionic behavior in this system.

In this work, operator-compensation based high order methods are presented to solve the Gross-Pitaevskii equation modeling Bose-Einstein condensation (BEC). We begin with the high-order approximation to the Laplacian by the central finite difference method combined with operator-compensation technique, and the Crank-Nicolson and time-splitting methods are then proposed for the time discretization. We show that the Crank-Nicolson operator-compensation method keeps the mass and energy conservation, while the time-splitting operator-compensation method only conserves the mass. Then by extending the high-order operator-compensation methods for the first order derivative, the time-splitting finite difference method is developed to solve the Gross-Pitaevskii equation with an angular momentum rotation term. Numerical results are given to test accuracy and verify the conservation properties.

A numerical calculation model is developed to study the coupled thermal dynamic performance in a cryogenic fuel tank under an intermittent sloshing excitation. Both external heat inputs and the intermittent excitation are realized by User-defined functions. The volume of fluid method is adopted to simulate fluid sloshing, coupled with the mesh motion treatment. Validated against related fluid sloshing experiments, the numerical model was turned out to be acceptable on fluid sloshing prediction. Cooled by subcooled liquid, vapor is always in condensation. The middle vapor pressure test point suffers less from the intermittent excitation and has a linear pressure decrease profile, while the middle liquid pressure test point has fluctuating variations. For vapor and interface temperature monitors, obvious temperature fluctuations appear in the second holding period. While for liquid test points, the temperature profiles experience intensive fluctuations during sloshing periods and stable temperature variation during holding periods. Due to the holding period of external excitation, the tank pressure reduction in intermittent sloshing case is less than that in continuous sloshing case. That is to say the tank pressure decrease rate could be adjusted by proper intermittent excitation. This work is significant to deeply understand fluid sloshing phenomenon under some irregular external excitations in fuel storage tanks.

The Bose–Einstein condensates (BECs) are seen during the studies in atomic optics, cavity opto-mechanics, cavity quantum electrodynamics, black-hole astrophysics, laser optics and atomtronics. Under investigation in this paper is a (2+1)-dimensional Gross–Pitaevskii equation with time-varying trapping potential which describes the dynamics of a (2+1)-dimensional BEC. Based on the Kadomtsev–Petviashvili hierarchy reduction, we construct the bilinear forms and the N th order rogue-wave solutions in terms of the Gramian. With the help of the analytic and graphic analysis, we exhibit the first- and second-order rogue waves under the influence of the strength of the interatomic interaction, α ( t ) , and of Ω ( t ) = ω R ∕ ω Z , where t is the scaled time, ω R and ω Z are the confinement frequencies in the radial and axial directions: When Ω ( t ) = 0 , the first-order rogue wave exhibits as an eye-shaped distribution; When Ω ( t ) is a periodic function, the rogue wave periodically raises; When Ω ( t ) is an exponential function, the rogue wave appears on the exponentially increasing background; When α ( t ) decreases, background and amplitude of the rogue wave both increase. The second-order rogue waves reach the maxima only once or three times when Ω ( t ) is a constant. With Ω ( t ) being the exponential function, the backgrounds of the second-order rogue waves exponentially increase with t increasing.

This study analyses the relationship between functional electrical stimulation (FES) and the induced torque for elbow flexion. The aim is to develop an FES-torque model that is simple to implement and understand, and is easily invertible so that the required FES for a desired assistive torque can be determined to enable control by FES. For accurate control, the FES-torque model must also be adaptable to time-varying behaviour of the muscle such as fatigue. The proposed FES-torque model is a sigmoid function, and a particle filter is implemented to estimate the change in parameters of the sigmoid function over time. The results show that the particle filter is successfully able to adapt to changes in the FES-induced torque and can be used to improve the estimate of FES-induced torque, with an overall average RMS error of 0.24 N.m or 7.85%. The improved FES-torque estimate allows for simple and more effective control of FES assistance and better fatigue management.

The formation mechanism of glass at the atomic scale has been under debate over centuries. In this work, we demonstrate that hybridization, as manifested by Mott’s pseudogap, has a strong influence on the bond length as well as atomic packing, which can potentially tailor the formation of metallic glasses at microscopic time and length scales. A p–d orbital hybridization between the post-transition metal Al and the transition metal was shown by the 27 Al isotropic shifts and the spin–lattice relaxation time of Zr–Co–Al alloys using nuclear magnetic resonance. These bonds lead to a charge transfer between the specific atomic pairs and the shrinkage of interatomic distances. Such chemical bonding favors the formation of metallic glasses by introducing a string-like structure and further stabilizes metallic glasses via a reduction in the density of states at the Fermi level. Our work has implications for understanding the glass formation mechanism at the electronic level and may open up new possibilities on the design of glass from the perspective of atomic interactions.

In order to obtain the real-time traffic flows between on-ramps and off-ramps of the ring expressway, a model to estimate the OD(origin-destination) matrix with consideration of the structural characteristics of the ring expressway is proposed in this paper.The ring expressway is looked as a loop network, without considering traffic congestion,the distance fromthe on-ramps to off-ramps that drivers may choose is not exceeding 1/2 of the loopperimeter. According to this principle, we use on-ramps’ flows to express mainline sections’ and off-ramps’ flows. These expressions form the simultaneous equations which can be solved with Gaussian Elimination, and the flow proportions between on and off-ramps (OD matrix) can be achieved. The propose method is applied to Xi’an Ring Expressway, the OD matrix is extracted from the estimated flow proportions between on and off ramps, and is compared with the actual survey. The model is verified to be feasible.

Magnetic skyrmions are topological magnetization textures that are characterized by the homotopy group of two dimensional spheres. Despite years of intensive research on skyrmions, the fundamental problem of the inertia of a skyrmion in driven motion remains unresolved. By properly taking into account a direct coupling between skyrmion motion and the correspondingly excited magnons, we identify a dynamical mass for the skyrmion in motion. The direct coupling between skyrmion motion and magnons can be employed to engineer skyrmion dynamics with magnons through ingenious material and geometry design., 16 pages, 4 figures

We analytically study the ground-state phase diagrams of ultracold bosons with various values of the effective magnetic quantum number $m$ in a state-dependent hexagonal optical lattice by using the generalized effective-potential Landau theory, where the site-offset energy between the two triangular sublattice A and B is tunable. Our analytical calculations of third-order corrections are in reasonably good agreement with the previous cluster Gutzwiller calculations. Furthermore, we reveal the reason why the regions of the Mott lobes $(n,n)$ in phase diagrams for $m=0.02$ are unexpectedly expanded with increasing $J/U$ in deep lattice.

Let M be a commutative cancellative monoid, and let R be an integral domain. The question of whether the monoid ring R [ x ; M ] is atomic provided that both M and R are atomic dates back to the 1980s. In 1993, Roitman gave a negative answer to the question for M = N 0 : he constructed an atomic integral domain R such that the polynomial ring R [ x ] is not atomic. However, the question of whether a monoid algebra F [ x ; M ] over a field F is atomic provided that M is atomic has been open since then. Here we offer a negative answer to this question. First, we exhibit for any infinite cardinal κ a torsion-free atomic monoid M of rank κ satisfying that the monoid domain R [ x ; M ] is not atomic for any integral domain R. Then for every n ≥ 2 and for each field F of finite characteristic we find a torsion-free atomic monoid M of rank n such that F [ x ; M ] is not atomic. Finally, we construct a torsion-free atomic monoid M of rank 1 such that Z 2 [ x ; M ] is not atomic.

Binarization of fringe patterns is a commonly used process in the fringe skeleton method for optical fringe pattern analysis. Most of the existing binarization algorithms of fringe patterns are based on the determination of gray level threshold. However, spatial intensity inhomogeneity induced by the uneven illumination makes the gray level threshold hard to determine. In this paper, we present a method for the binarization of fringe patterns based on a modified Fuzzy c-means clustering (FCM) algorithm. This method permits the clustering of pixels influenced by their immediate surroundings. The pixels in the fringe pattern are clustered into white fringes and black fringes without calculating thresholds. We evaluate the performance of this method by applying it to computer-simulated and real fringe patterns. Experimental results demonstrate that the proposed method can achieve the desired binarization results and perform better than the previous binarization methods, under non-uniform illumination conditions.

We study how the energy dispersion of bosonic atoms loaded into an optical lattice becomes modified due to periodic circular stirring of the lattice to the second order in the strength of stirring. If the lattice breaks mirror symmetry, the bosonic atoms may acquire a nonzero group velocity at the center of the Brillouin zone and produce a nonzero direct current. This effect is similar to the circular photogalvanic effect in solid-state physics. It can be used to transport neutral bosonic atoms in an optical lattice over a given distance in an arbitrary direction. However, when the drive frequency is detuned to avoid resonant transitions with energy absorption, we argue that the induced current is not persistent, but transient. An experimental study of the induced current relaxation could give answers to perplexing questions about equilibrization in driven systems., 17 pages, 7 figures; Extensive revision

Yaha condensate gas reservoir is condensate gas reservoir developed by gas injection in the Tarim Basin. The practice of gas injection in condensate gas reservoir shows that the key to improve gas injection effect is to control gas channeling. Dynamic monitoring shows that there is no instantaneous miscibility between dry gas and condensate gas during gas injection. Based on the principle of entropy increase and mass transfer kinetics, the phase behavior of condensate gas and dry gas in reservoir is analyzed theoretically. The new technique to improve condensate recovery is adopted for condensate gas field. By using the density difference and seepage characteristics of dry gas and condensate gas, the injected dry gas cap is formed at the top of the gas reservoir, and the three-dimensional displacement is realized by the expansion of dry gas cap. Gas injection gravity assisted flooding technology is to realize vertical displacement of injected gas through the expansion of dry gas cap by using gravity differentiation caused by gas density difference. This technology can keep the front edge of gas injection advance evenly and solve the problem of gas channeling in the process of cyclic gas injection.

Bose-Einstein condensates with their superfluidity property provide an interesting parallel to classical fluids. Due to the Kolmogorov spectrum of homogeneous turbulence the statistics of the incompressible velocity field is of great interest, but in superfluids obtaining quantities such as the statistics of the velocity field from the macroscopic wavefunction turns out be a complicated task; therefore, most of the work up to now has been numerical in nature. We made use of the Weak Wave Turbulence (WWT) theory, which provides the statistics of the macroscopic wavefunction, to obtain the statistics of the velocity field, which allowed us to produce a semi analytical procedure for extracting the incompressible energy spectrum in the WWT regime. This is done by introducing an auxiliary wavefunction that preserves the relevant statistical and hydrodynamical properties of the condensate but with a homogeneous density thus allowing for a simpler description of the velocity field., 11 pages, 5 figures

In this study, we reported plasmon-exciton coupling for excitation the surface plexciton in columnar thin film with a central exciton slab using the transfer matrix method in Kretschmann configuration. The optical absorption spectra for surface plasmon polariton, surface exciton and surface plexciton was investigated at different structural parameters in proposed structure. The characteristics of surface optical modes were analyzed and there was an anticrossing behavior between polariton branches of plexciton spectra. Localization of surface modes on interfaces and hybridization between plasmons and excitons at both interfaces of exciton slab were proved by the time-averaged Poynting vector. We found that the types of coupling regimes between plasmons and excitons from weak to strong could be achieved. We found a high Rabi splitting energy 840 meV corresponding to the time period 5 fs which includes to the fast energy transfer between surface plasmon polaritons and surface excitons.

We develop the theory of pretty good fractional revival in quantum walks on graphs using their Laplacian matrices as the Hamiltonian. We classify the paths and the double stars that have Laplacian pretty good fractional revival., Comment: 17 pages; journal version

The viscoelastic behavior of alkali and alkaline earth aluminophosphate glasses was studied. The energetic interpretation was based on the Arrhenius behavior of the relaxation modulus. With increasing aluminum content, the activation energy of the relaxation increased in the alkali series but decreased in the alkaline earth series. Dynamic viscoelasticity measurements revealed that the loss modulus, E”(ω), showed a crossover of the relaxation process at the glass transition temperatures. The activation energy below the transition temperature was close to the energies of internal friction or ionic self-diffusion. The energy above the transition temperature corresponded to the dissociation energies of alkali-oxygen or alkaline earth-oxygen single bonds. The different behavior in the energy of the relaxation modulus between alkali and alkaline earth series was due to weak bonds caused by adding alkali ions and the formation of crosslinking by low-coordinate aluminum polyhedra because of the presence of alkaline earth ions.

Interlayer exciton-polaron is formed arising from the exciton-surface optical (SO) phonons coupling in transition metal dichalcogenides (TMDS) van der Waals heterostructures, in which SO phonons are induced by the inserted hexagonal boron nitride (h-BN) and the coupling effect is evaluated by means of two unitary transformations. We find that the binding energy of interlayer exciton decreases obviously due to this exciton-polaron effect. The binding energy can be tuned by the numbers of inserted h-BN layers and the interlayer distance between two TMDS layers. Moreover, the critical temperature of quantum Bose gases composing of these interlayer excitons increases in a large scale due to the variations of binding energy. These theoretical results provide possible channels to adjust the properties of interlayer excitons in two-dimensional van der Waals heterostructures.