**Lump-soliton solutions to the Fokas system**

Publication date: Available online 25 January 2019Source: Physics Letters AAuthor(s): Jiguang Rao, Dumitru Mihalache, Yi Cheng, Jingsong HeAbstractIn this letter, we obtain families of semi-rational solutions termed lump-soliton solutions to the Fokas system by using the Hirota's bilinear method combined with the Kadomtsev-Petviashvili (KP) hierarchy reduction method. These exact semi-rational solutions illustrate the collision of lumps and dark-line solitons. Two different types of evolution scenarios occur: (a) fusion of lumps and dark-line solitons into dark-line solitons, and (b) fission of dark-line solitons into lump...

**Source: **Physics Letters A - January 26, 2019 **Category: **Physics **Source Type: **research

**Delay of terminal current in systems with abruptly changed Hamiltonian**

Publication date: Available online 24 January 2019Source: Physics Letters AAuthor(s): Mou Yang, Xian-Jin Ran, Bo Su, Rui-Qiang WangAbstractThe current response for the parameter change of a mesoscopic system is a practical issue for future's circuit design. Nowadays most considered cases are varied types of bias modulation, while the effect of change of conductor Hamiltonian is seldom addressed. In this paper, we investigate the response of ballistic transport induced by a sudden change of the conductor Hamiltonian. We formulize the terminal current in language of non-equilibrium Green's function. Our method is applied to ...

**Source: **Physics Letters A - January 25, 2019 **Category: **Physics **Source Type: **research

**Plasmon modes in MLG-2DEG heterostructures: Temperature effects**

Publication date: Available online 24 January 2019Source: Physics Letters AAuthor(s): Nguyen Van Men, Nguyen Quoc Khanh, Dong Thi Kim PhuongAbstractWe calculate the plasmon frequency and damping rate in a double-layer system made of monolayer graphene and GaAs quantum well at finite temperature using the random-phase-approximation dielectric function and taking into account the inhomogeneity of the dielectric background of the system. We show that the temperature, interlayer correlation parameters and dielectric background inhomogeneity affect significantly the plasmon frequencies and damping rates of the system. At low te...

**Source: **Physics Letters A - January 25, 2019 **Category: **Physics **Source Type: **research

**Investigating the nonequilibrium aspects of long-range Potts model: Refinement of critical temperatures and raw exponents**

Publication date: Available online 25 January 2019Source: Physics Letters AAuthor(s): Roberto da Silva, J.R. Drugowich de Felicio, Henrique A. FernandesAbstractIn this work, we analyse the q−state Potts model with long-range interactions through nonequilibrium scaling relations commonly used when studying short-range systems. We determine the critical temperature via an optimization method for short-time Monte Carlo simulations. The study takes into consideration two different boundary conditions and three different values of range parameters of the couplings. We also present estimates of some critical exponents, nam...

**Source: **Physics Letters A - January 25, 2019 **Category: **Physics **Source Type: **research

**Noise-induced multilevel Landau–Zener transitions: Density matrix investigation**

Publication date: Available online 21 January 2019Source: Physics Letters AAuthor(s): I.F. Nyisomeh, M.E. Ateuafack, L.C. FaiAbstractThe generalised multilevel Landau–Zener problem is solved by applying the density matrix technique within the framework of nonstationary perturbation theory. The exact survival probability is achieved as a proof of the Brundobler–Elzer hypothesis (Brundobler and Elzer (1993) [38]). The effect of classical Gaussian noise is investigated by averaging the solution over the noise realisation. A generalised formula for slow noise-induced transition probability is obtained and found to ...

**Source: **Physics Letters A - January 23, 2019 **Category: **Physics **Source Type: **research

**A quantummechanical derivation of the eigenvalues of the quadratic Casimir operator of the algebra SU(n) in Young tableau representation**

Publication date: Available online 22 January 2019Source: Physics Letters AAuthor(s): Éva SzőkeAbstractThe paper concerns the eigenvalues and eigenfunctions of the quadratic Casimir operator of the algebra SU(n) in the Young tableau representation. Our starting point is a concrete physical problem in second quantized formalism. We use quantummechanical and group theoretical vehicles to determine the aimed quantities. The tableaux are organized according to their eigenvalue. We also investigate the modification rules. (Source: Physics Letters A)

**Source: **Physics Letters A - January 23, 2019 **Category: **Physics **Source Type: **research

**Introduction in the band theory of molten salts**

Publication date: Available online 22 January 2019Source: Physics Letters AAuthor(s): Alexander L. ShimkevichAbstractThe electrochemical properties of molten salts are considered in the frame of band theory for ideal crystalline dielectrics. It turned out that metal impurities at low concentration in them generate the local electron levels in the wide band gap (>4 eV) of molten salt divided by 50 meV and more. They are occupied by electrons when Fermi level is approached to them from below. Then, the minor metal impurities fall out the molten salt when the electron occupation of their energy levels in the band gap achie...

**Source: **Physics Letters A - January 23, 2019 **Category: **Physics **Source Type: **research

**Comparison of diluted antiferromagnetic Ising models on frustrated lattices in a magnetic field**

Publication date: Available online 22 January 2019Source: Physics Letters AAuthor(s): Konstantin Soldatov, Alexey Peretyatko, Petr Andriushchenko, Konstantin Nefedev, Yutaka OkabeAbstractWe study diluted antiferromagnetic Ising models on triangular and kagome lattices in a magnetic field, using the replica-exchange Monte Carlo method. We observe seven and five plateaus in the magnetization curve of the diluted antiferromagnetic Ising model on the triangular and kagome lattices, respectively, when a magnetic field is applied. These observations contrast with the two plateaus observed in the pure model. The origin of multipl...

**Source: **Physics Letters A - January 23, 2019 **Category: **Physics **Source Type: **research

**Cooperative activation effect on H2O adsorption in MnO–Co catalyzed steam methane reforming**

Publication date: Available online 22 January 2019Source: Physics Letters AAuthor(s): Zhaoming Fu, Meng Liu, Qian Sun, Dongwei Ma, Zongxian YangAbstractSteam methane reforming is a very important chemical process in hydrogen production and solid oxide fuel cells (SOFCs). Cobalt (Co) is an important catalyst for dry and steam methane reforming. However, previous studies have confirmed that metal Co surfaces only have weak adsorption activity for H2O, which is evidently unfavorable for steam reforming. In this work we used first-principles simulations to study the activity of MnO–Co catalysts for the adsorption of H2O,...

**Source: **Physics Letters A - January 23, 2019 **Category: **Physics **Source Type: **research

**PageRank centrality for temporal networks**

Publication date: Available online 23 January 2019Source: Physics Letters AAuthor(s): Laishui Lv, Kun Zhang, Ting Zhang, Dalal Bardou, Jiahui Zhang, Ying CaiAbstractIn this paper, we propose a new centrality measure for ranking the nodes and time layers of temporal networks simultaneously, referred to as the f-PageRank centrality. The f-PageRank values of nodes and time layers in temporal networks are obtained by solving the eigenvector of a multi-homogeneous map. The existence and uniqueness of the proposed centrality measure are also guaranteed by existing results, under some reasonable conditions. The numerical experime...

**Source: **Physics Letters A - January 23, 2019 **Category: **Physics **Source Type: **research

**MMSE detection method in uplink massive MIMO systems based on quantum computing**

Publication date: Available online 23 January 2019Source: Physics Letters AAuthor(s): XiaoJun Wang, Jie Zhao, FanXu Meng, XuTao Yu, ZaiChen ZhangAbstractThe minimum mean square error (MMSE) detection method involved matrix inversion operation with excessive computational burden. In this paper, we develop an improved quantum linear system algorithm to solve matrix inversion problem of the MMSE detection method in uplink massive multiple-input and multiple-output (MIMO) systems. In order to apply reasonably the robust computational power of quantum computing, we optimize the preparation of the input state and the extraction ...

**Source: **Physics Letters A - January 23, 2019 **Category: **Physics **Source Type: **research

**Editors**

Publication date: 4 February 2019Source: Physics Letters A, Volume 383, Issue 7Author(s): (Source: Physics Letters A)

**Source: **Physics Letters A - January 23, 2019 **Category: **Physics **Source Type: **research

**Quantum information capsule and information delocalization by entanglement in multiple-qubit systems**

Publication date: Available online 21 January 2019Source: Physics Letters AAuthor(s): Koji Yamaguchi, Naoki Watamura, Masahiro HottaAbstractWhere do entangled multiple-qubit systems store information? For information injected into a qubit, this question is nontrivial and interesting since the entanglement delocalizes the information. So far, a common picture is that of a qubit and its purification partner sharing the information quantum mechanically. Here, we introduce a new picture of a single qubit in the correlation space, referred to as quantum information capsule (QIC), confining the information perfectly. This pictur...

**Source: **Physics Letters A - January 22, 2019 **Category: **Physics **Source Type: **research

**The intrinsical character of the electronic correlation in an electron gas**

Publication date: Available online 21 January 2019Source: Physics Letters AAuthor(s): Yu-Liang LiuAbstractBy introducing the phase transformation of electron operators, we map the equation of motion of an one-particle Green's function into that of a non-interacting one-particle Green's function where the electrons are moving in a time-depending scalar potential and pure gauge fields for a D-dimensional electron gas, and we demonstrate that the electronic correlation strength strongly depends upon the excitation energy spectrum and collective excitation modes of electrons. It naturally explains that the electronic correlati...

**Source: **Physics Letters A - January 22, 2019 **Category: **Physics **Source Type: **research

**Inherent spectral distortions in pump-probe Brillouin scattering spectroscopy**

Publication date: Available online 21 January 2019Source: Physics Letters AAuthor(s): V.I. KovalevAbstractIt is shown that the pump-probe technique in Brillouin scattering spectroscopy is accompanied by two specific distortions to a registered spectrum. The first appears due to an acoustic wave that unavoidably accompanies in a continuous medium the density wave driven by the pump and probe signals. The registered spectrum then splits to two spectral components, one corresponding to the propagation velocity of the driven density wave, and the other to the acoustic velocity. The other distortion is asymmetry of the spectrum...

**Source: **Physics Letters A - January 22, 2019 **Category: **Physics **Source Type: **research

**Spin switch effect in multiply connected superconductor-ferromagnet hybrid geometry**

Publication date: Available online 21 January 2019Source: Physics Letters AAuthor(s): B. KrunavakarnAbstractWe consider a superconducting spin valve in multiply connected superconductor-ferromagnet hybrid geometry such as a superconducting ring enclosed a ferromagnetic metal, in the framework of linearized Usadel equations. We simplify our model by considering the presence of the exchange field in the superconducting ring which allows us to manipulate magnetization orientations in parallel or antiparallel configurations by switching the weaker exchange field. In such geometry the superconducting ground state is activated t...

**Source: **Physics Letters A - January 22, 2019 **Category: **Physics **Source Type: **research

**Scanning tunneling microscopy studies in the heavy fermion system with even and odd hybridization**

Publication date: Available online 21 January 2019Source: Physics Letters AAuthor(s): Fu-Bin YangAbstractThe effect of even and odd hybridization for scanning-tunneling microscopy process in the heavy fermion system is studied by the nonequilibrium Green function method. It is found that an even hybridization leads to symmetric density of states (DOS), while an odd hybridization leads to the vanishing of the DOS of the nondiagonal term. Besides, the differential conductance under the even hybridization is the natural consequence of the existence of van Hove singularities. In the odd hybridization situation, the differentia...

**Source: **Physics Letters A - January 22, 2019 **Category: **Physics **Source Type: **research

**Effect of energy dependent cross-section on flow velocity measurements with charge exchange spectroscopy in magnetized plasma**

Publication date: Available online 21 January 2019Source: Physics Letters AAuthor(s): J. Chen, K. Ida, M. Yoshinuma, I. Murakami, T. Kobayashi, M.Y. Ye, B. LyuAbstractCharge exchange spectroscopy (CXS) is widely used to measure plasma flow velocity. Accurate measurement is heavily affected by energy dependent cross section between neutral atoms and impurity ions. One symmetric layout of poloidal CXS is applied on Large Helical Device. Correction velocity due to the cross section is exacted from total velocity when actual plasma flow velocity is acquired with the benefit of this layout. A linear relationship between correct...

**Source: **Physics Letters A - January 22, 2019 **Category: **Physics **Source Type: **research

**Rashba control to minimize circuit cost of quantum Fourier algorithm in ballistic nanowires**

Publication date: Available online 21 January 2019Source: Physics Letters AAuthor(s): A.H. Homid, M.R. Sakr, A.-B.A. Mohamed, M. Abdel-Aty, A.-S.F. ObadaAbstractThe presented work provides a new prospective of quantum computer hardware development through ballistic nanowires with Rashba effect. We address Rashba effect as a possible mechanism to realize novel qubit gates in nanowires. We apply our results to the design of a new quantum circuit for Fourier algorithm, which shows an improved quantum cost in terms of the number of gates. The current system can be successfully implemented to increase the production of quantum ...

**Source: **Physics Letters A - January 22, 2019 **Category: **Physics **Source Type: **research

**Axial momentum for the relativistic Majorana particle**

Publication date: Available online 21 January 2019Source: Physics Letters AAuthor(s): H. ArodźAbstractThe Hilbert space of states of the relativistic Majorana particle consists of normalizable bispinors with real components, hence the usual momentum operator −i∇ can not be defined in this space. For this reason, we introduce the axial momentum operator, −iγ5∇ as a new observable for this particle. In the Heisenberg picture, the axial momentum contains a component which oscillates with the amplitude proportional to m/E, where E is the energy and m the mass of the particle. The presence of the ...

**Source: **Physics Letters A - January 22, 2019 **Category: **Physics **Source Type: **research

**Noise-Induced Multilevel Landau-Zener Transitions: Density Matrix Investigation**

Publication date: Available online 21 January 2019Source: Physics Letters AAuthor(s): I.F. Nyisomeh, M.E. Ateuafack, L.C. FaiAbstractThe generalised multilevel Landau-Zener problem is solved by applying the density matrix technique within the framework of nonstationary perturbation theory. The exact survival probability is achieved as a proof of the Brundobler-Elzer hypothesis [J. Phys. A: Math. Gen. 26, 1211 (1993)]. The effect of classical Gaussian noise is investigated by averaging the solution over the noise realisation. A generalised formula for slow noise-induced transition probability is obtained and found to agree ...

**Source: **Physics Letters A - January 22, 2019 **Category: **Physics **Source Type: **research

**Formation of intermediate coupling optical polarons and bipolarons in two-dimensional systems**

Publication date: Available online 22 January 2019Source: Physics Letters AAuthor(s): S. Dzhumanov, P.J. Baimatov, Sh.T. Inoyatov, Sh.S. Djumanov, A.G. GulyamovAbstractThe formation of the optical polaron and bipolaron in two-dimensional (2D) systems is studied in the intermediate electron–phonon coupling regime. The total energies of the 2D polaron and bipolaron are calculated by using the Buimistrov–Pekar method of canonical transformations. The obtained results are compared with other existing results obtained by using the Feynman path integral method and the modified Lee–Low–Pines unitary transf...

**Source: **Physics Letters A - January 22, 2019 **Category: **Physics **Source Type: **research

**Edge intensity-based community measurement in complex networks**

Publication date: Available online 18 January 2019Source: Physics Letters AAuthor(s): Hao LongAbstractCommunity is the dominant structure of complex networks. In recent years, community detection has become a heavily researched issue in network science, and many algorithms have been proposed to solve it. However, how to evaluate these algorithms and measure the strength of community structures is still an open problem. The modularity, as well as many of its variants, is widely used for this purpose, and maximizing such metrics is also a main approach to uncover communities, but this technique has a resolution limit problem...

**Source: **Physics Letters A - January 20, 2019 **Category: **Physics **Source Type: **research

**Cooperation in the spatial public goods game with the second-order reputation evaluation**

Publication date: Available online 18 January 2019Source: Physics Letters AAuthor(s): Yuetian Dong, Gang Hao, Juan Wang, Chen Liu, Chengyi XiaAbstractThe existence of reputation can significantly promote the level of cooperation within the human population. In the recent years, most of the researches were based on binary image score or first-order evaluation standard. In this paper, we propose a second-order reputation evaluation model, in which the individual's image score will change not only in accordance with his own strategy, but also the reputation value of neighbors. Individuals try to enhance their reputation to co...

**Source: **Physics Letters A - January 20, 2019 **Category: **Physics **Source Type: **research

**Double Hopf bifurcation induces coexistence of periodic oscillations in a diffusive Ginzburg–Landau model**

Publication date: Available online 16 January 2019Source: Physics Letters AAuthor(s): Yanfei Du, Ben Niu, Yuxiao Guo, Jianquan LiAbstractWe perform bifurcation analysis in a complex Ginzburg–Landau system with delayed feedback under the homogeneous Neumann boundary condition. We calculate the amplitude death region, and it turns out that the boundary of the amplitude death region consists of two Hopf bifurcation curves with wave number zero. The existence conditions for double Hopf bifurcations are established. Taking the feedback strength and time delay as bifurcation parameters, normal forms truncated to the third ...

**Source: **Physics Letters A - January 18, 2019 **Category: **Physics **Source Type: **research

**SERS-signal optimised AgNPs-plated-ZnO nanoflower-like structure synthesised for sensing applications**

Publication date: Available online 17 January 2019Source: Physics Letters AAuthor(s): Tianhui Jiao, Felix Y.H. Kutsanedzie, Jing Xu, Annavaram Viswadevarayalu, Md Mehedi Hassan, Huanhuan Li, Yi Xu, Quansheng ChenAbstractAgNPs-plated-ZnO nanoflower (NFs)-like structures (Ag@ZnO NFs) with optimised signals were synthesised via wet chemical method at different temperatures (50 - 80 °C). The enhancement factors (EFs) computed for the resultant Ag@ZnO ranged between 2.36 - 8.46×107 obtained at the different temperatures using 4-aminothiophenol (4-ATP). The achieved EF results indicate Ag@ZnO synthesised at 50 °C g...

**Source: **Physics Letters A - January 18, 2019 **Category: **Physics **Source Type: **research

**Transient thin film flow of nonlinear radiative Maxwell nanofluid over a rotating disk**

Publication date: Available online 17 January 2019Source: Physics Letters AAuthor(s): Jawad Ahmed, Masood Khan, Latif AhmadAbstractIn this letter, a mathematical model for transient nature thin film flow of Maxwell nanofluid over a rotating disk is studied in the presence of a uniform magnetic field and non-linear thermal radiation. The Brownian motion and thermophoresis features due to nanofluid are captured by adopting the Buongiorno model. The prime emphasize is to explore the temperature field and nanoparticles volume fraction in nanofluid thin film flow. The reduced system of differential equations is solved numerical...

**Source: **Physics Letters A - January 18, 2019 **Category: **Physics **Source Type: **research

**Thermal properties of triangle nitrogen-doped graphene nanoribbons**

Publication date: Available online 17 January 2019Source: Physics Letters AAuthor(s): Bing Yang, Dongbo Li, Liang Qi, Tianbo Li, Ping YangAbstractWe investigate the thermal properties of triangle nitrogen-doped graphene nanoribbons (TNGNs) with different nitrogen-doped concentrations (0.11% to 2.31%) at different temperatures (200K∼600K) using non-equilibrium molecular dynamics. The results show that the nitrogen atoms doped at the edge of the defect can increase the thermal conductivity of graphene nanoribbons, but with the increase of the nitrogen-doped concentrations from 0.11% to 2.31%, the thermal conductivity dec...

**Source: **Physics Letters A - January 18, 2019 **Category: **Physics **Source Type: **research

**Study of the q-Gaussian distribution with the scale index and calculating entropy by normalized inner scalogram**

Publication date: Available online 17 January 2019Source: Physics Letters AAuthor(s): Mahmut Akıllı, Nazmi Yılmaz, K. Gediz AkdenizAbstractIn this paper, we discuss a method based on wavelet analysis for the study of the q-index of the Gaussian distribution. We derive q-index from the scale index, iscale, using the expression; q≡1+2iscale where iscale is a wavelet based tool for measuring the degree of aperiodicity of a dynamical system in the range of 0≤iscale≤1. We show that this expression gives consistent results with the numerical approach of q-Gaussian distribution which determines the degree of non-ex...

**Source: **Physics Letters A - January 18, 2019 **Category: **Physics **Source Type: **research

**The Role of CdCl2 Treatments and Annealing in the Formation of Sintered CdTe Nanocrystal Solar Cells**

Publication date: Available online 17 January 2019Source: Physics Letters AAuthor(s): G. Jain, A. Ahnood, A. Chanaewa, K. Fox, P. MulvaneyAbstractSolution processing of CdTe nanocrystals is a promising approach for the fabrication of low cost photovoltaic devices at low process temperatures. However despite the inherent advantages of this approach, the nanoscale physical mechanisms underlying the fabrication process are not well understood. Here we demonstrate that chemical treatment of CdTe nanoparticles leads to the production of a deep valence band edge. However, the removal of ligands also introduces sizable quantities...

**Source: **Physics Letters A - January 18, 2019 **Category: **Physics **Source Type: **research

**Heat and mass transfer analysis of time-dependent tangent hyperbolic nanofluid flow past a wedge**

Publication date: Available online 16 January 2019Source: Physics Letters AAuthor(s): S.M. Atif, S. Hussain, M. SagheeAbstractThe candid intension of this article is to inspect the heat and mass transfer of a magnetohydrodynamic tangent hyperbolic nanofluid. The nanofluid flow has been assumed to be directed by a wedge on its way. In addition, the collective stimulus of the convective heating mode with thermal radiation is inspected. The governing set of PDEs is rendered into that of the coupled nonlinear ODEs. The resulting ordinary differential equations are then solved by the well known shooting technique for two differ...

**Source: **Physics Letters A - January 17, 2019 **Category: **Physics **Source Type: **research

**Stay-eat or run-away: Two alternative escape behaviors**

Publication date: Available online 16 January 2019Source: Physics Letters AAuthor(s): Shuai Zhang, Mingyong Liu, Xiaokang Lei, Yunke HuangAbstractPursuit-and-evasion behavior in groups of animals is a phenomenon that can be easily observed in nature. Immediate flight upon detection is a common but not exclusive response for prey with both stay-eat behavior and run-away behavior occur during the predation process. It remains unclear why these two contrasting survival tactics appear, what the triggering conditions are and what internal mechanisms are at play. Here we investigate the effect of energy level on the behavior of ...

**Source: **Physics Letters A - January 17, 2019 **Category: **Physics **Source Type: **research

**Magnetic anisotropy of ferromagnetic metals in low-symmetry systems**

Publication date: Available online 16 January 2019Source: Physics Letters AAuthor(s): Yoshishige Suzuki, Shinji MiwaAbstractWe have constructed an analytic formula to treat the perpendicular magnetic anisotropy energy in ferromagnetic metals with low symmetry, such as C4V and C3V. We find that the anisotropy energy is proportional to a part of the expectation values of the orbital angular momentum and magnetic dipole operator. Although the result is similar to the model proposed by Laan (1998) [2], we have derived a concrete expression for the spin-flip virtual excitation process term, which can be dominant in atoms with s...

**Source: **Physics Letters A - January 17, 2019 **Category: **Physics **Source Type: **research

**Green's function approach to the impurity state in the Lieb lattice**

Publication date: Available online 16 January 2019Source: Physics Letters AAuthor(s): Rui ZhuAbstractWavefunction of an impurity attached to the Lieb lattice is considered by directly computing the Green's function (GF) for the nearest-neighbor tight-binding model. By replacing the lattice GF with a GF array including all the nine GFs defining on the three-atom unit cell of the Lieb lattice, an accurate and efficient numerical technique is developed. Agreement of both the real and imaginary components of the GF between numerical simulation of the lattice GF and continuum-space Fourier transformation is achieved in the whol...

**Source: **Physics Letters A - January 17, 2019 **Category: **Physics **Source Type: **research

**A special type of explosion of basin boundary**

Publication date: Available online 16 January 2019Source: Physics Letters AAuthor(s): Guiqin Kong, Yongxiang ZhangAbstractWe study a special type of explosion of a basin boundary set in an archetypal oscillator. A typical feature is that the basin boundaries change the number of basins separating at the same time. Before the explosion, a basin boundary contains some Wada points of ten basins. After the explosion, the basin boundary contains some Wada points of eighteen basins. The underlying mechanism for the explosion is investigated by the heteroclinic tangency and Lambda lemma. Basin entropy and boundary basin entropy a...

**Source: **Physics Letters A - January 17, 2019 **Category: **Physics **Source Type: **research

**Double Hopf bifurcation induces coexistence of periodic oscillations in a diffusive Ginzburg-Landau model**

Publication date: Available online 16 January 2019Source: Physics Letters AAuthor(s): Yanfei Du, Ben Niu, Yuxiao Guo, Jianquan LiAbstractWe perform bifurcation analysis in a complex Ginzburg-Landau system with delayed feedback under the homogeneous Neumann boundary condition. We calculate the amplitude death region, and it turns out that the boundary of the amplitude death region consists of two Hopf bifurcation curves with wave number zero. The existence conditions for double Hopf bifurcations are established. Taking the feedback strength and time delay as bifurcation parameters, normal forms truncated to the third order ...

**Source: **Physics Letters A - January 17, 2019 **Category: **Physics **Source Type: **research

**Noncommutative geometry of the quantum clock**

Publication date: Available online 16 January 2019Source: Physics Letters AAuthor(s): S. Mignemi, N. UrasAbstractWe introduce a model of noncommutative geometry that gives rise to the uncertainty relations recently derived from the discussion of a quantum clock. We investigate the dynamics of a free particle in this model from the point of view of doubly special relativity and discuss the geodesic motion in a Schwarzschild background. (Source: Physics Letters A)

**Source: **Physics Letters A - January 17, 2019 **Category: **Physics **Source Type: **research

**Nonlinear analysis of an improved continuum model considering mean-field velocity difference**

Publication date: Available online 16 January 2019Source: Physics Letters AAuthor(s): Zihao Wang, Rongjun Cheng, Hongxia GeAbstractBased on the velocity gradient model, an extended continuum model with consideration of the mean-field velocity difference is proposed in this paper. By using the linear stability theory, the linear stability criterion of the new model is gained, which proved that mean-field velocity difference has significant influence on stability of traffic flow. The KdV–Burgers equation is derived by using non-linear analysis method and the evolution of density wave near the neutral stability line is ...

**Source: **Physics Letters A - January 17, 2019 **Category: **Physics **Source Type: **research

**Input-to-state stability analysis for memristive BAM neural networks with variable time delays**

Publication date: Available online 16 January 2019Source: Physics Letters AAuthor(s): Yong Zhao, Jürgen Kurths, Lixia DuanAbstractIn this paper, we are concerned with input-to-state stability of a class of memristive bidirectional associative memory (BAM) neural networks with variable time delays. Based on a nonsmooth analysis and set-valued maps, some novel sufficient conditions are obtained for the input-to-state stability of such networks, which extended some known results as particular cases. Finally, a numerical example is presented to illustrate the feasibility and effectiveness of our results. (Source: Physics Letters A)

**Source: **Physics Letters A - January 17, 2019 **Category: **Physics **Source Type: **research

**On the Thomas–Fermi model at the Planck scale**

Publication date: Available online 15 January 2019Source: Physics Letters AAuthor(s): Homa Shababi, Kamel OurabahAbstractMany quantum gravity theories predict a minimal length of the order of the Planck length. In this letter, the Thomas–Fermi model is reformulated by taking into account such a prescription. A generalized Thomas–Fermi equation is derived, that reduces to the usual one in the absence of a minimal length. As an application, the model is used to study the dielectric screening process. Estimations of the Fermi length are given for star interior. (Source: Physics Letters A)

**Source: **Physics Letters A - January 16, 2019 **Category: **Physics **Source Type: **research

**Editors**

Publication date: 28 January 2019Source: Physics Letters A, Volume 383, Issue 6Author(s): (Source: Physics Letters A)

**Source: **Physics Letters A - January 16, 2019 **Category: **Physics **Source Type: **research

**On the issue of zero point energy in Bose–Einstein condensates**

Publication date: Available online 11 January 2019Source: Physics Letters AAuthor(s): F.A. DeeneyAbstractFollowing on our earlier work in this area, here we examine in some detail the physical mechanism involved in the Bose–Einstein condensation process. In particular we emphasise the significance of the zero value of the chemical potential at and below the critical temperature. The molar zero-point energy (ZPE) for an ideal gas of He4 atoms in our new analysis is estimated and found to be very close to that calculated for an ideal Fermi gas of He3 atoms under the same conditions. This gives numerical support to our ...

**Source: **Physics Letters A - January 12, 2019 **Category: **Physics **Source Type: **research

**Quantum shape effects and novel thermodynamic behaviors at nanoscale**

We report also a torque due to quantum shape effects. Furthermore, we introduce isoformal, shape preserving, process which opens the possibility of a new generation of thermodynamic cycles operating at nanoscale with unique features.Graphical abstract (Source: Physics Letters A)

**Source: **Physics Letters A - January 12, 2019 **Category: **Physics **Source Type: **research

**On the issue of zero point energy in Bose-Einstein condensates**

Publication date: Available online 11 January 2019Source: Physics Letters AAuthor(s): F.A. DeeneyAbstractFollowing on our earlier work in this area, here we examine in some detail the physical mechanism involved in the Bose-Einstein condensation process. In particular we emphasise the significance of the zero value of the chemical potential at and below the critical temperature. The molar zero-point energy (ZPE) for an ideal gas of He4 atoms in our new analysis is estimated and found to be very close to that calculated for an ideal Fermi gas of He3 atoms under the same conditions. This gives numerical support to our theory...

**Source: **Physics Letters A - January 11, 2019 **Category: **Physics **Source Type: **research

**Benchmark study of the SF-MI phase transition of the Bose–Hubbard model with density-induced tunneling**

Publication date: Available online 11 January 2019Source: Physics Letters AAuthor(s): Tao Wang, Tao YingAbstractThe Bose–Hubbard model (BHM) is a standard model which describes the quantum behavior of ultracold bosons in optical lattice. When tuning the model parameters, a quantum phase transition from superfluid (SF) phase to Mott insulating (MI) phase emerges. However, an extra tunneling process – the density-induced tunneling – is usually ignored in the standard BHM. Using process-chain method, we give a thorough study of the phase diagram of the BHM with density-induced tunneling in different particle...

**Source: **Physics Letters A - January 11, 2019 **Category: **Physics **Source Type: **research

**Large magnetoresistance and perfect spin filter effect in Fe doped SnS2 half-metallic monolayers: A first principles study**

Publication date: Available online 11 January 2019Source: Physics Letters AAuthor(s): Yi Liu, Shaoqiang Guo, Jiangang Yu, Huicai ZhongAbstractIn this work, the spin-resolved transport properties of the Fe doped SnS2 monolayer devices have been investigated. The results show that the doping systems have the transport properties of negative differential resistance, large magnetoresistance effect and near 100% spin polarization effect when the magnetization directions of two electrodes are in parallel. Moreover, the mechanisms for the properties also have been discussed. The original reason of these results could be due to th...

**Source: **Physics Letters A - January 11, 2019 **Category: **Physics **Source Type: **research

**Robust pulses for high fidelity non-adiabatic geometric gate operations in an off-resonant three-level system**

Publication date: Available online 11 January 2019Source: Physics Letters AAuthor(s): Ying Yan, Jie Lu, Lin Wan, Joel MoserAbstractWe propose a method to design pulses in a resonant three-level system to enhance the robustness of non-adiabatic geometric gate operations. By optimizing the shape of the pulse envelope, we show that the gate operations are more robust against frequency detuning than they are with Gaussian and square pulses. Our method provides a way to design pulses that can be employed in a system where robustness against frequency variations or inhomogeneous broadening is required, and may be extended to ens...

**Source: **Physics Letters A - January 11, 2019 **Category: **Physics **Source Type: **research

**Enhancement of ablation rate and production of colloidal nanoparticles by irradiation of metals with nanosecond pulsed laser in presence of external electric field**

Publication date: Available online 11 January 2019Source: Physics Letters AAuthor(s): Hossein Mozaffari, Mohammad Hossein MahdiehAbstractThis paper presents the results of experimental study on the effect of electric field on the ablation rate during the nanosecond pulsed laser ablation of aluminum and copper in deionized water. The effect of electric field strength on the material removal rate and its mechanisms were investigated both in the electric field parallel and perpendicular to the laser beam path schemes. The ablation rate was estimated by measuring the dimensions of craters on the target induced by laser. The cr...

**Source: **Physics Letters A - January 11, 2019 **Category: **Physics **Source Type: **research

**Realizing reliable logic and memory function with noise-assisted Schmitt trigger circuits**

Publication date: Available online 11 January 2019Source: Physics Letters AAuthor(s): Lei Zhang, Wenbin Zheng, Fuhong Min, Aiguo SongAbstractSchmitt trigger is a comparator circuit with hysteresis, implemented by applying positive feedback to a noninverting input. Recently, it has been verified that noise under certain condition can help nonlinear circuit to realize reliable logical stochastic resonance (LSR). In this letter, we demonstrate that, without any modifications, Schmitt trigger can operate flexibly both as logic operation and latch operation in an optimal noise range. In traditional Schmitt trigger, the hysteres...

**Source: **Physics Letters A - January 11, 2019 **Category: **Physics **Source Type: **research

**Engineering of carbon-based superlight spin filter with negative differential resistance**

Publication date: Available online 9 January 2019Source: Physics Letters AAuthor(s): Xi Zuo, Li Han, Heming Li, Xiaoteng Li, Jingfen Zhao, Bin Cui, De-Sheng LiuAbstractBased on density functional theory and non-equilibrium Green's function, we investigate the edge hydrogenation and oxidation effects on the spin transport of devices consisting of a zigzag C2N nanoribbon (ZC2NNR) embedded in zigzag graphene nanoribbons in parallel (P) and antiparallel (AP) spin configurations. The results show that device with edge hydrogenation exhibits dual spin filtering effect in AP spin configuration and obvious negative differential re...

**Source: **Physics Letters A - January 10, 2019 **Category: **Physics **Source Type: **research