A lattice Maxwell system with discrete space-time symmetry and local energy-momentum conservation
Publication date: Available online 5 December 2018Source: Physics Letters AAuthor(s): Jianyuan Xiao, Hong Qin, Yuan Shi, Jian Liu, Ruili ZhangAbstractA lattice Maxwell system is developed with gauge-symmetry, symplectic structure and discrete space-time symmetry. Noether's theorem for Lie group symmetries is generalized to discrete group symmetries for the lattice Maxwell system. As a result, the lattice Maxwell system is shown to admit a discrete local energy-momentum conservation law corresponding to the discrete space-time symmetry. A lattice model that respects all local conservation laws and geometric structures is as...
Source: Physics Letters A - December 6, 2018 Category: Physics Source Type: research

Ground-state properties of dilute one-dimensional Bose gas with three-body repulsion
Publication date: Available online 5 December 2018Source: Physics Letters AAuthor(s): Volodymyr PastukhovAbstractWe determined perturbatively the low-energy universal thermodynamics of dilute one-dimensional bosons with the three-body repulsive forces. The final results are presented for the limit of vanishing potential range in terms of three-particle scattering length. An analogue of Tan's energy theorem for considered system is derived in generic case without assuming weakness of the interparticle interaction. We also obtained an exact identity relating the three-body contact to the energy density. (Source: Physics Letters A)
Source: Physics Letters A - December 6, 2018 Category: Physics Source Type: research

Global versus local superintegrability of nonlinear oscillators
Publication date: Available online 5 December 2018Source: Physics Letters AAuthor(s): Stephen C. Anco, Angel Ballesteros, Maria Luz GandariasAbstractLiouville (super)integrability of a Hamiltonian system of differential equations is based on the existence of globally well-defined constants of the motion, while Lie point symmetries provide a local approach to conserved integrals. Therefore, it seems natural to investigate in which sense Lie point symmetries can be used to provide information concerning the superintegrability of a given Hamiltonian system. The two-dimensional oscillator and the central force problem are used...
Source: Physics Letters A - December 6, 2018 Category: Physics Source Type: research

The effects of the electrochemical capacitance on the ac admittance phase of a quantum point contact
Publication date: Available online 5 December 2018Source: Physics Letters AAuthor(s): Jianzhuang Yin, Shuwei Chen, Li SongAbstractWe investigate the ac admittance of a quantum point contact (QPC) in quantum hall regime. Experiment data shows that the phase of the QPC admittance is not transmission independent. With the increasing of the QPC transmission, the phase increases in large magnetic field, but stays constant in small field. The theoretical works indicated that the Coulomb interaction between the counter-propagate channels is the main reason for the non-constant phase in large field. Besides this, we also studied t...
Source: Physics Letters A - December 6, 2018 Category: Physics Source Type: research

Stress annealing effect on the piezomagnetic coefficient of Fe–Al–B alloys
The objective is to evaluate the potential use of these alloys as smart materials of force sensors. The study comprises two alloys with compositions (Fe0.87Al0.13)98.4B1.6 (Al13) and (Fe0.82Al0.18)98.4B1.6 (Al18). The microstructure, hysteresis loops and B vs. σ|H were analyzed before and after the SA. Regarding the force sensitivity, the SA increased the piezomagnetic coefficient d33⁎ due the introduction of an extrinsic anisotropy in both Fe–Al–B alloys. Moreover, the stress range, in which the piezomagnetic coefficient d33⁎ is linear, is higher after the SA. Concerning the single phase (Fe0.87Al0.1...
Source: Physics Letters A - December 5, 2018 Category: Physics Source Type: research

Azimuthal asymmetry of coherent Cherenkov radiation from a tilted bunch
Publication date: Available online 4 December 2018Source: Physics Letters AAuthor(s): S.Yu. Gogolev, A.P. PotylitsynAbstractModern accelerator technologies may provide electron beams consisting of ultrashort bunches with transverse sizes, which are much larger than bunches with longitudinal sizes. The spectral-angular characteristics of coherent Cherenkov radiation (CChR) produced by the former type have thus been considered. We simulated the characteristics of CChR and those from a single charge on the basis of the polarisation current model, which allowed us to consider finite sizes for the target Cherenkov radiator. We ...
Source: Physics Letters A - December 5, 2018 Category: Physics Source Type: research

I–V characteristics and conductance of strained SWCNTs
We present a new procedure to investigate the I–V characteristics and the conductance for strained SWCNTs. These electronic transport properties have been studied theoretically at zero temperature for zig-zag, armchair and chiral SWCNTs under the effect of the uniaxial tension and torsional strain. The analytical expression of the energy spectrum in the tight binding approximation has been used to calculate the induced current and the conductance through Landauer–Büttiker formalism. It is shown that the conductance for unstrained CNTs at initial values of the voltage can take discrete values which are equa...
Source: Physics Letters A - December 5, 2018 Category: Physics Source Type: research

Implications of spectral hole burning on the manipulation of spatial Goos–Hänchen shift in an atomic cell
We present a new scheme to report on Goos–Hänchen (GH) shift experienced by the Gaussian light beam interacting with an optical cavity filled with four-level sodium atomic medium in the spectral hole burning region with and without Doppler broadening effect. Theoretical atomic density-matrix formalism is employed to obtain the susceptibility of atomic medium while the stationary-phase-theory is used to compute the GH shift in the reflected and transmitted probe beams subjected to control fields. A steep normal slope of dispersion is observed with a maximum and zero probability of transmission and reflection coef...
Source: Physics Letters A - December 4, 2018 Category: Physics Source Type: research

Strong entanglement criterion involving momentum weak values
Publication date: Available online 3 December 2018Source: Physics Letters AAuthor(s): A. Valdés-Hernández, L. de la Peña, A.M. CettoAbstractIn recent years weak values have been used to explore interesting quantum features in novel ways. In particular, the real part of the weak value of the momentum operator has been widely studied, mainly in connection with Bohmian trajectories. Here we focus on the imaginary part and its role in relation with the entanglement of a bipartite system. We establish an entanglement criterion based on weak momentum correlations, that allows to discern whether the entanglem...
Source: Physics Letters A - December 4, 2018 Category: Physics Source Type: research

Path integrals with discarded degrees of freedom
Publication date: Available online 3 December 2018Source: Physics Letters AAuthor(s): Luke M. ButcherAbstractWhenever variables ϕ=(ϕ1,ϕ2,…) are discarded from a system, and the discarded information capacity S(x) depends on the value of an observable x, a quantum correction ΔVeff(x) appears in the effective potential [1]. Here I examine the origins and implications of ΔVeff within the path integral, which I construct using Synge's world function. I show that the ϕ variables can be ‘integrated out’ of the path integral, reducing the propagator to a sum of integrals over observable paths x(...
Source: Physics Letters A - December 4, 2018 Category: Physics Source Type: research

Stress annealing effect on the piezomagnetic coefficient of Fe-Al-B alloys
The objective is to evaluate the potential use of these alloys as smart materials of force sensors. The study comprises two alloys with compositions (Fe0.87Al0.13)98.4B1.6 (Al13) and (Fe0.82Al0.18)98.4B1.6 (Al18). The microstructure, hysteresis loops and B vs. σ|H were analyzed before and after the SA. Regarding the force sensitivity, the SA increased the piezomagnetic coefficient d33⁎ due the introduction of an extrinsic anisotropy in both Fe-Al-B alloys. Moreover, the stress range, in which the piezomagnetic coefficient d33⁎ is linear, is higher after the SA. Concerning the single phase (Fe0.87Al0.13)98.4B1.6 a...
Source: Physics Letters A - December 4, 2018 Category: Physics Source Type: research

Doping-induced giant rectification and negative differential conductance (NDC) behaviors in zigzag graphene nano-ribbon junction
Publication date: Available online 3 December 2018Source: Physics Letters AAuthor(s): Huan-Yan Fu, Feng Sun, Ran Liu, Yu-Qing Suo, Jun-Jie Bi, Chuan-Kui Wang, Zong-Liang LiAbstractBy p-type and n-type doping on the electrode edges of V-notched zigzag graphene nano-ribbons (ZGNRs), four V-notched ZGNR-based PN-junctions are designed theoretically. The electronic transport properties of the doped and un-doped V-notched ZGNRs are studied applying non-equilibrium Green's function method combined with the density functional theory. The numerical results show that, the doped systems are less conductive than the un-doped system, ...
Source: Physics Letters A - December 4, 2018 Category: Physics Source Type: research

Revisiting the admissibility of non-contextual hidden variable models in quantum mechanics
Publication date: Available online 30 November 2018Source: Physics Letters AAuthor(s): Atul Singh Arora, Kishor Bharti, ArvindAbstractWe construct a non-contextual hidden variable model consistent with all the kinematic predictions of quantum mechanics (QM). The famous Bell–KS theorem shows that non-contextual models which satisfy a further reasonable restriction are inconsistent with QM. In our construction, we define a weaker variant of this restriction which captures its essence while still allowing a non-contextual description of QM. This is in contrast to the contextual hidden variable toy models, such as the on...
Source: Physics Letters A - December 2, 2018 Category: Physics Source Type: research

Directed LPA: Propagating labels in directed networks
Publication date: Available online 30 November 2018Source: Physics Letters AAuthor(s): Xue LiAbstractIgnoring edge directionality and considering the graph as undirected is a common approach to detect communities in directed networks. However, it's not a meaningful way due to the loss of information captured by the edge property. Even if Leicht and Newman extended the original modularity to a directed version to address this issue, the problem of distinguishing the directionality of the edges still exists in maximizing modularity algorithms. To this direction, we extend one of the most famous scalable algorithms, namely la...
Source: Physics Letters A - December 2, 2018 Category: Physics Source Type: research

Generating Majorana modes in one-dimensional p-wave superconductor with second-neighbor couplings by periodic kicking
Publication date: Available online 1 December 2018Source: Physics Letters AAuthor(s): X.P. Li, C.F. Li, L.C. Wang, L. ZhouAbstractGenerating many Majorana modes (MMs) within one single system is a constructive method for experimental observation of MMs in condensed-matter systems. In this paper, we show that by adding periodic δ-function kicks on the chemical potential, a large number of MMs can be generated in the one-dimensional p-wave superconductor system with second-neighbor couplings. The Floquet theory has been used to analyse the stroboscopic properties and the winding number can be used to characterize the t...
Source: Physics Letters A - December 2, 2018 Category: Physics Source Type: research

Width dependent structural and electrical properties of zigzag ZnTe nanoribbons
Publication date: Available online 29 November 2018Source: Physics Letters AAuthor(s): Monoj Das, Bikash C. GuptaAbstractWe carry out density functional theory based investigation to understand the structural and electrical properties such as atomic structure, edge energy, band gap, and work function of zigzag ZnTe nanoribbons. It is found that the zigzag nanoribbons may be stabilized by passivating the edge atoms with Hydrogen, Oxygen or Fluorine atoms. Our study reflects that zigzag ZnTe nanoribbons with smaller width behave like semiconductor. However, they exhibit a transition from semiconducting phase to a metallic ph...
Source: Physics Letters A - November 30, 2018 Category: Physics Source Type: research

Thermodynamic calculation of spin scaling functions
Publication date: Available online 29 November 2018Source: Physics Letters AAuthor(s): George RuppeinerAbstractCritical phenomena theory centers on the scaled thermodynamic potential per spin ϕ(β,h)=|t|pY(h|t|−q), with inverse temperature β=1/T, h=−βH, ordering field H, reduced temperature t=t(β), critical exponents p and q, and function Y(z) of z=h|t|−q. I discuss calculating Y(z) with the information geometry of thermodynamics. Scaled solutions are found to obtain with three admissible functions t(β): 1) t=e−Jβ, 2) t=β−1, and 3) t=βC−β, whe...
Source: Physics Letters A - November 30, 2018 Category: Physics Source Type: research

Parametric X-ray Radiation from powders
Publication date: Available online 29 November 2018Source: Physics Letters AAuthor(s): V.I. Alekseev, A.N. Eliseyev, E. Irribarra, I.A. Kishin, A.S. Klyuev, A.S. Kubankin, R.M. Nazhmudinov, S.V. Trofymenko, P.N. ZhukovaAbstractParametric X-ray Radiation (PXR) produced in powders has been observed for the first time. PXR spectra were measured under observation angles of 150° and 180° during the interaction of relativistic 7 MeV electrons with a tungsten powder. All the PXR peaks that theoretically can be produced in the studied energy region were registered. The performed absolute comparison of the experiment with t...
Source: Physics Letters A - November 30, 2018 Category: Physics Source Type: research

While rotating while cloaking
Publication date: Available online 28 November 2018Source: Physics Letters AAuthor(s): Liliang Zhou, Shiyao Huang, Meng Wang, Run Hu, Xiaobing LuoAbstractInvisible optical and thermal cloaking have been explored as the typical demonstrations of the transformation optics and thermotics theory. However, the existing cloaks are realized by only one-coordinate transformation, and the cloaking layout, i.e. the form of electromagnetic wave/heat passing around the invisible region, is single for a long time. Here, we propose a new rotated thermal cloak which can unify the conventional cloaking and rotating together, and realize t...
Source: Physics Letters A - November 29, 2018 Category: Physics Source Type: research

Exact and quasiclassical Green's functions of two-dimensional electron gas with Rashba–Dresselhaus spin–orbit interaction in parallel magnetic field
Publication date: Available online 28 November 2018Source: Physics Letters AAuthor(s): I.V. Kozlov, Yu.A. KolesnichenkoAbstractNew exact and asymptotical results for the one particle Green's function of 2D electrons with combined Rashba–Dresselhaus spin–orbit interaction in the presence of in-plane uniform magnetic field are presented. A special case that allows an exact analytical solution is also highlighted. To demonstrate the advantages of our approach we apply the obtained Green's function to calculation of electron density and magnetization. (Source: Physics Letters A)
Source: Physics Letters A - November 29, 2018 Category: Physics Source Type: research

First-principles calculations of magnetic edge states in zigzag CrI3 nanoribbons
Publication date: Available online 28 November 2018Source: Physics Letters AAuthor(s): Wei Jiang, Shujing Li, Haitao Liu, Guo Lu, Fawei Zheng, Ping ZhangAbstractCrI3 monolayer has recently drawn much attention due to its two-dimensional long range ferromagnetic order. We find that CrI3 nanoribbons, which are strips of CrI3 monolayer, can be used as building blocks of nanodevices. In this paper, we studied the atomic and electronic structures of CrI3 zigzag nanoribbons by using first-principles calculations. CrI3 zigzag nanoribbons are also ferromagnet. Interestingly, edge states exist in the system and play an important ro...
Source: Physics Letters A - November 29, 2018 Category: Physics Source Type: research

Quantifying time irreversibility using probabilistic differences between symmetric permutations
Publication date: Available online 28 November 2018Source: Physics Letters AAuthor(s): Wenpo Yao, Wenli Yao, Jun Wang, Jiafei DaiAbstractTo simplify the quantification of time irreversibility, we employ order patterns instead of the raw multi-dimension vectors in time series, and considering the existence of forbidden permutation, we propose a subtraction-based parameter to measure probabilistic differences between symmetric permutations for time irreversibility. Two chaotic models, logistic and Henon systems, and reversible Gaussian process and their surrogate data are used to validate the time-irreversible measure, and t...
Source: Physics Letters A - November 29, 2018 Category: Physics Source Type: research

Community Detection in Social Networks based on Improved Label Propagation Algorithm and Balanced Link Density
Publication date: Available online 27 November 2018Source: Physics Letters AAuthor(s): Ehsan Jokar, Mohammad MoslehAbstractNowadays, community detection has been raised as one of the key research areas in the online social networks mining. One of the most common algorithms in this field is label propagation algorithm (LPA). Even though the LPA method has advantages such as simplicity in understanding and implementation, as well as linear time complexity, it has an important disadvantage of the uncertainty and instability in outcomes, that is, the algorithm detects and reports different combinations of communities in each r...
Source: Physics Letters A - November 28, 2018 Category: Physics Source Type: research

Entanglement in four qubit states: Polynomial invariant of degree 2, genuine multipartite concurrence and one-tangle
Publication date: Available online 27 November 2018Source: Physics Letters AAuthor(s): M.A. Jafarizadeh, M. Yahyavi, N. Karimi, A. HeshmatiAbstractCharacterization of the multipartite mixed state entanglement is still a challenging problem. This is due to the fact that the entanglement for the mixed states, in general, is defined by a convex-roof extension. That is the entanglement measure of a mixed state ρ of a quantum system can be defined as the minimum average entanglement of an ensemble of pure states. In this paper, we show that polynomial entanglement measures of degree 2 of even-N qubits X states is in the ful...
Source: Physics Letters A - November 28, 2018 Category: Physics Source Type: research

A (2+1)-dimensional KdV equation and mKdV equation: symmetries, group invariant solutions and conservation laws
Publication date: Available online 27 November 2018Source: Physics Letters AAuthor(s): Gangwei Wang, A.H. KaraAbstractIn this paper, we analyse the (2+1)-dimensional KdV and mKdV equations. Firtly, on the basis of the extended Lax pair, we derive these equations. Thereafter, the symmetry generators are determined followed by the application of the mCK method. Finally, conservation laws (including higher order) are studied. (Source: Physics Letters A)
Source: Physics Letters A - November 28, 2018 Category: Physics Source Type: research

Hydrogen passivation tunes edge magnetism in the ZMoS2NR with a sulfur vacancy
Publication date: Available online 27 November 2018Source: Physics Letters AAuthor(s): J. Pan, X.Y. Zhou, R. Wang, J.H. He, L.J. Meng, J.G. HuAbstractWe performed density functional theory study on electronic structure, magnetic properties and stability of zigzag MoS2 nanoribbons with a S vacancy (ZMoS2NRs-VS) and considered their different edge passivation. The ZMoS2NR-VS systems are magnetic metals with ferromagnetic (FM) edge states. The magnetic moments are greatly influenced by the site of S vacancy and edge passivation because the vacancy and edge states significantly change the structure of the systems. Importantly,...
Source: Physics Letters A - November 28, 2018 Category: Physics Source Type: research

Implications of spectral-hole burning on the manipulation of spatial Goos–Hänchen shift in an atomic cell
We present a new scheme to report on Goos–Hänchen (GH) shift experienced by the Gaussian light beam incident at the plane optical interface filled with four-level sodium atomic medium in the spectral-hole burning region with and without Doppler broadening effect. Theoretical atomic density-matrix formalism is employed to obtain the susceptibility of atomic medium while the stationary-phase-theory is used to compute the GH shift in the reflected and transmitted probe beams subjected to control fields. A steep normal slope of dispersion is observed with a maximum and zero probability of transmission and reflection...
Source: Physics Letters A - November 28, 2018 Category: Physics Source Type: research

Terahertz planar lenses based on plasmonic metasurfaces
Publication date: Available online 28 November 2018Source: Physics Letters AAuthor(s): Chang Yang, Yun Shen, Yanqiang Xie, Qi Zhou, Xiaohua Deng, Juncheng CaoAbstractPlasmonic planar lenses on silicon substrate are designed to realize terahertz (THz) wave focusing. Super-unit-cells containing eight different resonant units are presented to construct eight concentric rings on the silicon substrate. By controlling of the position distribution of the resonant units, it is shown that focusing at 4.3 THz can be achieved. Moreover, due to that the eight units can steer THz wave and keep phase gradient in frequency range of 4.2 t...
Source: Physics Letters A - November 28, 2018 Category: Physics Source Type: research

Relaxation of a dislocation in a nanocrystallite
Publication date: Available online 27 November 2018Source: Physics Letters AAuthor(s): Vladimir P. ZhdanovAbstractExperimental studies of dislocations in nanoparticles are just beginning. The corresponding theoretical models are still lacking. In this context, the author analyzes relaxation of a dislocation in a nanoparticle. Mechanistically, this process is considered to occur primarily via dislocation drift induced by the stress-related image forces. Elementary dislocation displacements include the formation of a kink at one of the sides of the dislocation line, its diffusion along this line, and annihilation at the oppo...
Source: Physics Letters A - November 27, 2018 Category: Physics Source Type: research

Conservation laws of nonconservative nonholonomic system based on Herglotz variational problem
Publication date: Available online 27 November 2018Source: Physics Letters AAuthor(s): Yi Zhang, Xue TianAbstractThe generalized variational principle of Herglotz type provides a variational method for describing nonconservative or dissipative processes. The purpose of this letter is to extend this variational principle to a first order linear nonholonomic system and study the conservation laws of the nonconservative nonholonomic system based on Herglotz variational problem. A new differential variational principle of the nonconservative nonholonomic system is proposed, which is based on Herglotz variational problem. And t...
Source: Physics Letters A - November 27, 2018 Category: Physics Source Type: research

A general method for constructing vector integrable lattice systems
Publication date: Available online 23 November 2018Source: Physics Letters AAuthor(s): Ruguang Zhou, Na Li, Jinyan ZhuAbstractA method for generating vector-value integrable analogies of integrable lattice systems or integrable differential-difference equations is presented. The basic ingredient of the method is to insert permutation matrices. We formulate the zero-curvature representations and Hamiltonian structures of the resulting vector lattice systems. The effectiveness of the method is illustrated using some examples such as the Volterra lattice, the Belov–Chaltikian lattice, the Ablowitz–Ladik lattice an...
Source: Physics Letters A - November 24, 2018 Category: Physics Source Type: research

TBOR-shaped electro-optic modulator with dual output based on double-layer graphene
Publication date: Available online 22 November 2018Source: Physics Letters AAuthor(s): Zhiquan Li, Landi Bai, Erdan Gu, Ruijie Xie, Xin Li, Wenchao LiAbstractWe proposed an electro-optic modulator with two-bus one-ring (TBOR) structure to improve the extinction ratio and reduce insert loss. It has a dual output compared with one-bus one-ring structure. In addition, double-layer graphene makes it possible for the modulation in the visible to mid-infrared wavelength range. It shows that this new electro-optic modulator can present two switching states well with low insertion loss, high absorption and high extinction ratio. A...
Source: Physics Letters A - November 23, 2018 Category: Physics Source Type: research

Cavitation occurring in capillary tubes
Publication date: Available online 22 November 2018Source: Physics Letters AAuthor(s): Steve Q. CaiAbstractSurface etches caused by cavitation often occur behind the blade of a rapidly rotating propeller or on a vibrating surface where liquid is subjected to suddenly reduced or oscillating saturation pressure. This phenomenon has never been reported in a continuous capillary pipe in which flow pressure varied gently without injection of external radiation energy. On the other aspect, acoustically tinkling signals were recognized decades ago during operation of the oscillation capillary heat pipe, but lacking of vigorous sc...
Source: Physics Letters A - November 23, 2018 Category: Physics Source Type: research

A new model equation for nonlinear Rossby waves and some of its solutions
Publication date: Available online 22 November 2018Source: Physics Letters AAuthor(s): Quansheng Liu, Ruigang Zhang, Liangui Yang, Jian SongAbstractIn this paper, we investigate the (2+1) dimensional nonlinear Rossby waves under non-traditional approximation. Using the asymptotic methods of multiple scales and weak nonlinear perturbation expansions, we derive a new modified Zakharov-Kuznetsov equation from the barotropic potential vorticity equation with the complete Coriolis parameter, the topography and the dissipation. Based on the new auxiliary equation method, new exact solutions of the new mZK equation are obtained w...
Source: Physics Letters A - November 23, 2018 Category: Physics Source Type: research

Electron injection in laser wake-field acceleration by using near critical layers
Publication date: Available online 22 November 2018Source: Physics Letters AAuthor(s): Saeed Mirzanejhad, Maisam TaghipourAbstractA method for enhancing trapped electrons in the laser wake-field acceleration in dilute plasma is proposed. In this method, a thin layer with near critical density is placed in front of the dilute plasma. Upon interaction of this layer with a short and high power laser pulse, a relatively large number of layer electrons are injected in dilute plasma. Some of these electrons are trapped in the wake-field of transmitted laser pulse. Particle in cell simulation is used to demonstrate this method. S...
Source: Physics Letters A - November 22, 2018 Category: Physics Source Type: research

Adsorption of CO gas molecules on zigzag BN/AlN nanoribbons for nano sensor applications
Publication date: Available online 22 November 2018Source: Physics Letters AAuthor(s): Rachana Yogi, Neeraj K. JaiswalAbstractFirst-principle calculations have been performed to study the sensing of CO gas in various considered configurations. The adsorption of CO on zigzag BN nanoribbon (ZBNNR) and zigzag AlN nanoribbon (ZAlNNR) was modelled in five different possibilities. The effect of CO adsorption is to reduce the band gap in both types (BN/AlN) of the nanoribbons. Interestingly, a finite magnetic moment (0.96 μB for ZBNNR and 0.687 μB for ZAlNNR) has been obtained which depends upon the adsorption configuration...
Source: Physics Letters A - November 22, 2018 Category: Physics Source Type: research

Enhancement of pupil-masked wavelength-scale gas-filled flat acoustic lens based on anomaly apodization effect
Publication date: Available online 22 November 2018Source: Physics Letters AAuthor(s): Constanza Rubio, Daniel Tarrazó-Serrano, Oleg V. Minin, Antonio Uris, Igor V. MininAbstractIn this letter, the improvement in focus by the use of a pupil mask produced in an acoustic mesoscale cuboid particle filled with CO2 is reported. Thereby, the result shows that the pupil mask increases the sound intensity and also increases the resolution (or a reduction of the full width at half maximum, FWHM) in focus compared to the non-masked one. These results are important because they confirm the effect of abnormal amplitude apodizat...
Source: Physics Letters A - November 22, 2018 Category: Physics Source Type: research

Laplace transform approach for the dynamics of N qubits coupled to a resonator
Publication date: Available online 22 November 2018Source: Physics Letters AAuthor(s): Mirko Amico, Oleg L. Berman, Roman Ya. KezerashviliAbstractAn approach to use the method of Laplace transform for the perturbative solution of the Schrödinger equation at any order of the perturbation for a system of N qubits coupled to a cavity with n photons is suggested. We investigate the dynamics of a system of N superconducting qubits coupled to a common resonator with time-dependent coupling. To account for the contribution of the dynamical Lamb effect to the probability of excitation of the qubit, we consider counter-rotatin...
Source: Physics Letters A - November 22, 2018 Category: Physics Source Type: research

Linearizable boundary value problems for the nonlinear Schrödinger equation in laboratory coordinates
Publication date: Available online 22 November 2018Source: Physics Letters AAuthor(s): Katelyn Plaisier Leisman, Gino Biondini, Gregor KovacicAbstractBoundary value problems for the nonlinear Schrödinger equation on the half line in laboratory coordinates are considered. A class of boundary conditions that lead to linearizable problems is identified by introducing appropriate extensions to initial-value problems on the infinite line, either explicitly or by constructing a suitable Bäcklund transformation. Various soliton solutions are explicitly constructed and studied. (Source: Physics Letters A)
Source: Physics Letters A - November 22, 2018 Category: Physics Source Type: research

Spectral engineering and tunable thermoelectric behavior in a quasiperiodic ladder network
Publication date: Available online 22 November 2018Source: Physics Letters AAuthor(s): Amrita Mukherjee, Atanu NandyAbstractDouble-stranded quasiperiodic copper mean arrangement has been studied in respect of its electronic property and thermoelectric signature. The two-arm network is demonstrated by a tight-binding Hamiltonian. The eigenspectrum of such aperiodic mesh that does not convey translational invariance, is significantly dependent on the parameters of the Hamiltonian. It is observed that specific correlation between the parameters obtained from the commutation relation between the on-site energy and overlap inte...
Source: Physics Letters A - November 22, 2018 Category: Physics Source Type: research

Molecular dynamics simulations on the effect of nanovoid on shock-induced phase transition in uranium nitride
Publication date: Available online 19 November 2018Source: Physics Letters AAuthor(s): Y.L. Li, J. Cai, D. MoAbstractThe Angular-Dependent Potential (ADP) proposed by Tseplyaev et al. was used to study the structural behavior of uranium nitride (UN) under shock pressure by molecular dynamics (MD) simulations. Based on the calculations of shock velocity US and particle velocity UP, the results show that a pressure-induced phase transition of Fm−3m→R−3m structure in UN occurs at 35 GPa, and it agrees well with experimental results of 30–32 GPa. We also considered the effect of nanovoid on the phase tra...
Source: Physics Letters A - November 21, 2018 Category: Physics Source Type: research

Can freestanding Xene monolayers behave as excitonic insulators?
Publication date: Available online 19 November 2018Source: Physics Letters AAuthor(s): Matthew N. Brunetti, Oleg L. Berman, Roman Ya. KezerashviliAbstractWe predict a phase transition in freestanding monolayer Xenes from the semiconducting phase to the excitonic insulating (EI) phase can be induced by reducing an external electric field below some critical value which is unique to each material. The splitting of the conduction and valence bands due to spin–orbit coupling at non-zero electric fields leads to the formation of A and B excitons in the larger or smaller band gap, with correspondingly larger or smaller bin...
Source: Physics Letters A - November 21, 2018 Category: Physics Source Type: research

Dynamical current–current correlation in two-dimensional parabolic Dirac systems
Publication date: Available online 19 November 2018Source: Physics Letters AAuthor(s): Chen-Huan WuAbstractWe theoretically investigate the current–current correlation of the two-dimensional (2D) parabolic Dirac system in hexogonal lattice. The analytical expressions of the random phase approximation (RPA) susceptibility, Ruderman–Kittel–Kasuya–Yosida (RKKY) Hamiltonian, and the diamagnetic orbital susceptibility in noninteracting case base on the density–density or current–current correlation function are derived and quantitatively analyzed. In noninteracting case, the dynamical polariz...
Source: Physics Letters A - November 21, 2018 Category: Physics Source Type: research

Spin-orbital coupling and magnetic properties of Ir-based double perovskites with different 5dn (n = 3, 4, 5) states
Publication date: Available online 19 November 2018Source: Physics Letters AAuthor(s): Yong-Feng Li, Kai-Cheng Zhang, Yong LiuAbstractWe have investigated the spin and orbital moments of Ir-based double perovskites with 5dn (n = 3, 4, 5) states by local spin-density approximation with spin-orbital coupling and Hubbard correlation (LSDA+SOC+U). Our calculations reveal that the ratio of orbital to spin momentum Lz/Sz approaches to certain values for the double perovskites with different 5dn (n = 3, 4, 5) shell fillings. Based on d orbits, a spin-orbital coupling model with exchange splitting is proposed and it can well descr...
Source: Physics Letters A - November 21, 2018 Category: Physics Source Type: research

Classifying the ground-state phases of spin–orbit coupled spin-2 Bose–Einstein condensate in momentum space
Publication date: Available online 20 November 2018Source: Physics Letters AAuthor(s): Ji-Guo Wang, Wei Wang, Shi-Jie YangAbstractThe ground-state phases of two-dimensional spin-2 Bose–Einstein condensate with Rashba spin–orbit coupling are studied. For the equal strengths of the density-density interaction and the spin-exchange interaction, we classify the ground-state phases into four types of stable phases with spin–orbit coupling and spin singlet-pairing interaction in momentum space, i.e., the ring phase, the stripe phase, the triangular phase and the square phase. With increasing the spin–orbi...
Source: Physics Letters A - November 21, 2018 Category: Physics Source Type: research

General N-solitons and their dynamics in several nonlocal nonlinear Schrödinger equations
Publication date: Available online 20 November 2018Source: Physics Letters AAuthor(s): Jianke YangAbstractGeneral N-solitons in three recently-proposed nonlocal nonlinear Schrödinger equations are presented. These nonlocal equations include the reverse-space, reverse-time, and reverse-space–time nonlinear Schrödinger equations, which are nonlocal reductions of the Ablowitz–Kaup–Newell–Segur (AKNS) hierarchy. It is shown that general N-solitons in these different equations can be derived from the same Riemann–Hilbert solutions of the AKNS hierarchy, except that symmetry relations on t...
Source: Physics Letters A - November 21, 2018 Category: Physics Source Type: research

Spin orbit coupled Bose Einstein condensate in a two dimensional bichromatic optical lattice
Publication date: Available online 20 November 2018Source: Physics Letters AAuthor(s): Z. OztasAbstractWe numerically investigate the localization of Bose Einstein condensate (BEC) with spin orbit coupling in a two dimensional bichromatic optical lattice. We study localization in weakly interacting and non-interacting regimes. The existence of stationary localized states in the presence of spin–orbit and Rabi couplings has been confirmed. We find that spin orbit coupling favors localization, whereas Rabi coupling has a slight delocalization effect. (Source: Physics Letters A)
Source: Physics Letters A - November 21, 2018 Category: Physics Source Type: research

Novel design for bifurcation control in a delayed fractional dual congestion model
Publication date: Available online 20 November 2018Source: Physics Letters AAuthor(s): Chengdai Huang, Tongxing Li, Liming Cai, Jinde CaoAbstractThis letter puts forward an ingenious feedback control method with parametric delay to manipulate bifurcation control for a delayed fractional dual congestion model. By employing time delay as a bifurcation parameter, the local dynamics involving stability and Hopf bifurcation is examined. The control efforts are realized with or without time delay in the strength of feedback control. It suggests that the stability performance is consumedly elevated by exploiting the parametric de...
Source: Physics Letters A - November 21, 2018 Category: Physics Source Type: research

Self-organization of ultra-thin uranium film
Publication date: Available online 16 November 2018Source: Physics Letters AAuthor(s): Xianggui Li, Shujing Li, Menglei Li, Mei Zhou, Fawei Zheng, Ping ZhangAbstractWe have studied the adsorption behaviors of uranium (U) atoms coated graphene at different coverage ratios using first-principles calculations. Isolated U atom is demonstrated to be more likely to stay on the hollow site of graphene with a large adsorption energy of 2.80 eV and high magnetic moment of 5.07 μB. It seems that two U atoms tend to adsorb on the nearest neighbor hollow sites of graphene. As the concentration of U atom increases, no U-dimer or U-c...
Source: Physics Letters A - November 18, 2018 Category: Physics Source Type: research

Spark-based improved Basin-Hopping Monte Carlo algorithm for structural optimization of alloy clusters
Publication date: Available online 16 November 2018Source: Physics Letters AAuthor(s): Yuan-Hua Yang, Jun-Fa Zhang, Jin-Bo Wang, Xian-Bin Xu, Gui-Fang Shao, Yu-Hua WenAbstractCoPt alloy clusters are promising candidates for catalysts in fuel-cell applications because of their enhanced catalytic performances compared with pure Pt clusters. In this article, an improved Basin-Hopping Monte Carlo (BHMC) algorithm is proposed to optimize the stable structures of CoPt clusters with different sizes and compositions, and the Spark parallel framework is employed to accelerate the structural optimizations. The results show that the ...
Source: Physics Letters A - November 18, 2018 Category: Physics Source Type: research