International Journal of Modern Physics B

In this work, we report the effect of the spin–orbit (SO) interaction on the band structure of TlInSe₂. Calculation was performed by implementing density functional theory (DFT) method. Our results show that SO interaction is significant for two high symmetrical point ($\mathrm{\Gamma }$, $T$) and line ($\kappa$, $A$) of Brillouin zone in the band structure and negligible changes was observed in the bands near the Fermi level. The maximum SO splitting is $\sim$0.9 eV.

We study the propagations of quantum resources encoded in orbital angular momenta of two photons via the turbulent maritime atmosphere. The decay characteristics of entanglement, discord and coherence are studied for the cases of increasing propagation distance, different azimuthal quantum numbers, inner scales of turbulence and wavelengths of light source. We find that the entanglement does not suffer sudden vanishing for the one-side turbulent channels case while entanglement disappears nonasymptotically for a general case of two-side different turbulent channels similar to the specific case of two-side identical turbulent channels. Entanglement, discord and coherence have quite different decay laws and coherence possesses more robustness against the turbulence than entanglement and discord. Our results show that larger azimuthal quantum numbers and larger wavelength of light source may boost the quality of distributions of quantum resources in turbulent maritime atmosphere.

Formation energies of cadmium sulfide clusters are calculated with the help of density functional theory. The investigated structures include clusters that represent the CdS three main phases, wurtzite, zincblende and rock-salt. The investigation includes electronic, vibrational and thermal properties. CdS clusters are represented by wurtzoids, diamondoids and cuboids for the three phases, wurtzite, zincblende and rock-salt, respectively. The energy gap of the largest investigated molecules approaches that of bulk experimental 2.42 eV. The calculated longitudinal optical (LO) vibrational mode is 304.2 cm${}^{-1}$ which is in good agreement with the experimental bulk value of 305 cm${}^{-1}$. To calculate Gibbs free energy, enthalpy and entropy of formation for the clusters, we redefined these quantities so that they represent the difference between the CdS formation energy and their constitutes Cd and S clusters energy. The calculated Gibbs free energy of formation, enthalpy and entropy of the investigated clusters approach that of bulk. Wurtzoids are more stable than diamondoids and cuboids with the release of more heat as deduced from their cluster Gibbs energy and enthalpy of formation. The entropy of clusters is dependent on the size of the cluster. The present method draws a relation between known solid state phases and small cluster calculations.

In this paper, we have given the quantum transfer matrix, quantum dispersion relation, quantum transmissivity and reflectivity of one-dimensional photonic crystals with the quantum theory of photon. We have studied the quantum transmission characteristic of different structure one-dimensional photonic crystals, which include mirror and nonmirror structures, with and without defect, and the defects are active and inactive media. On that basis, we compared the dispersion relation, transmissivity and reflectivity of quantum with classical for one-dimensional photonic crystals, and found they are identical, which indicate the quantum theory approach of photonic crystals is true, it can further study the quantum topological property of photonic crystals, such as quantum Zak phase, Chern number and quantum edge state and so on.

Stable wave propagation is important for heart health, however, the electromagnetic radiation could affect normal signal propagation of heart, even make a sudden cardiac arrest. In this paper, the effect of electromagnetic radiation on the propagation of stable target wave generated by linear feedback control is studied in detail. It is confirmed that there are different transitions of electrical activities in cardiac tissue, which are transitions from target wave to spiral wave, some isolated islands of pattern waves coexisted, broken pattern and even the quiescent state, are generated when the electromagnetic field is imposed on the cardiac tissue in three ways. Furthermore, it is interesting to find there are different real affected regions, in which the electrical activities of nodes are destroyed, when the radiation signal is imposed on the cardiac tissue in different ways. It is also found the kinds of dynamical behaviors in the media are dependent on the real affected region. These results state that electromagnetic radiation could change the electrical activities, even destroy and suppress the wave propagation of wave source, and the ways of electromagnetic radiation imposed on the media are also important.

The effect of gas molecule (H₂CO, NO, NO₂, O₂ and SO₂) adsorption on the electronic and magnetic properties of Mn-doped graphene (MnG) is investigated by first-principles calculations in the framework of density functional theory (DFT). Our study reveals that after H₂CO, NO, NO₂ and SO₂ adsorption, MnG transforms from half-metal to semiconductor, and this transformation indicates that MnG’s conductivity is changed significantly. Meanwhile, O₂ adsorption has no influence on MnG’s original electronic property. Therefore, the substrate of MnG is highly sensitive to H₂CO, NO, NO₂ and SO₂. The reconfiguration of electron distribution caused by gas adsorption dramatically alters the spin polarization distribution of the combined system, that is, NO₂ and H₂CO adsorption leads to local spin polarization, whereas O₂, NO and SO₂ adsorption result in complete spin polarization. In addition, the external electric field (E-field) is varied from −0.50 V/Å to +0.50 V/Å then applied to the adsorption system. A strong interaction is observed between gas and MnG with a positive E-field as reflected in the enhancement of adsorption energy. The interaction is obviously weakened by introducing the E-field in the negative direction. Hence, the adsorption strength and sensitivity of gas on MnG can be effectively tuned by the E-field. The results can serve as useful references for the design of graphene-based gas sensor.

We adopted the first-principles calculations within density functional theory (DFT) to investigate the structures, elastic, and electronic properties of ternary TiNi-X alloys with different four main-group elements by using the CASTEP code. The lattice constants and volumes increase gradually from C to Pb. The mechanical stability has been discussed by utilizing the criteria. All alloys are mechanically stable except TiNiPb. The values of Young’s modulus gradually decreased. Oppositely, the values of $B$/$G$ and $\nu$ are increased, respectively. The ductility/brittleness of alloys is distinct. In addition, the width of pseudogap is gradually decreased, which is consistent with hardness, showing that the covanlency of TiNi-X alloys is decreased. Similarly, these properties of the remaining alloys are also discussed and results are stated in the paper.

Molecular dynamics simulations were employed to investigate the aggregation of monocrystal and polycrystal nanoparticles. The lattice structure, displacement vector, potential energy, shrinkage ratio, relative gyration radius and mean square displacement of the two systems are compared. The results indicate that the aggregation of polycrystal nanoparticles is more drastic than that of monocrystal nanoparticles. Besides, the polycrystal nanoparticles are found contacted and melted at lower-temperature than that of monocrystal nanoparticles. The reason for all these phenomena is that there is additional surface energy in the grain boundary of polycrystal nanoparticles.

The real throughput of a network is dependent on the adopted routing algorithm. In this study, we further analyze the influence of real-time traffic condition and travel distance on network throughput in a dynamic transportation environment, and define a mathematical model to describe the routing cost for a packet spending to travel along a path with considering real-time traffic condition and travel distance. Based on the model, this paper proposes a routing strategy by imposing the minimum cost. Experimental results show that the proposed routing strategy is efficient in improving network throughput and balancing traffic load.

Reliable neural circuits provide feasible ways to estimate the information encoding and signal exchange between neurons so that more physical effects can be considered and explained. Electrical synapse benefits signal propagation and neurons can give rapid response selection under an external stimulus. Chemical synapse plays a standing biological function by the continuous release of neurotransmitter. Gap junction coupling can estimate the effect of electrical synapse coupling as resistor-based voltage coupling while chemical synapse coupling shows a complex form in synapse currents. In this paper, two FitzHugh–Nagumo neuron circuits are connected by resistor and induction coil, and thus field coupling is activated to realize synchronization. It gives possible guidance to explain the synapse function from physical view. These circuit equations are obtained and scale transformation is applied to get the dimensionless dynamical systems. Furthermore, the same scheme is used to discuss synchronization realization between Hindmarsh–Rose neuron models. It is found that synchronization can be suppressed when the coupling resistor is in series with the induction coil in which only one coupling channel is open. However, complete synchronization can be enhanced when the coupling resistor is paralleled with the induction coil because two coupling channels are activated simultaneously. As a result, appropriate adjustment and selection for the coupling electric devices can induce transition from synchronization to desynchronization between neural circuits, which indicates the self-adaption of synapse when two types of synapse are activated together.

In two-dimensional (2D) electron systems in a magnetic field, the Coulomb interaction among charge carriers, under Landau quantization, essentially governs a variety of many-body phenomena while there are also phenomena, such as the (integer) quantum Hall effect, that appear unaffected by the interaction. It is pointed out that the response of 2D electrons to spatially-uniform potentials and fields enjoys a long-wavelength gauge symmetry, associated with cyclotron motion of electrons, that leaves the Coulomb interaction invariant and that thus naturally explains why cyclotron resonance (as implied by Kohn’s theorem) and the quantized Hall conductance appear insensitive to the interaction. It is discussed, in the light of this new long-wavelength gauge symmetry, how Dirac electrons in graphene and conventional 2D electrons differ in cyclotron-resonance characteristics and the quantum Hall effect.

Mortality introduces an intrinsic time scale into the scale-invariant Brownian motion. This fact has important consequences for different statistics of Brownian motion. Here we are telling three short stories, where spontaneous death, such as radioactive decay, puts a natural limit to “lifetime achievements” of a Brownian particle. In story 1 we determine the probability distribution of a mortal Brownian particle (MBP) reaching a specified point in space at the time of its death. In story 2 we determine the probability distribution of the area A = ${\int }_0^T$ x(t)dt of an MBP on the line. Story 3 addresses the distribution of the winding angle of an MBP wandering around a reflecting disk in the plane. In stories 1 and 2 the probability distributions exhibit integrable singularities at zero values of the position and the area, respectively. In story 3 a singularity at zero winding angle appears only in the limit of very high mortality. A different integrable singularity appears at a nonzero winding angle. It is inherited from the recently uncovered singularity of the short-time large-deviation function of the winding angle for immortal Brownian motion.

To solve the problems that the existing pressure generators require high mechanical excitation frequency, need large manufacturing cost and are hard to control, a kind of pressure generator with low-frequency based on magnetic fluid is proposed in this paper. Magnetic fluid possesses the advantages of both magnetism of solid magnetic material and fluidity of liquid. The first-order buoyancy of magnetic fluid changes with low frequency alternating magnetic field. Based on this, the superimposed magnetic field is generated by electrifying the conical solenoid coil connected with the long solenoid coil with magnetic core in parallel. Magnetic field and magnetic force in the model are analyzed, then the relationship between input current and output pressure is calculated. In addition, the experimental platform is built and the performance of the device is tested. The result shows that the pressure generator can produce the corresponding pressure signal according to the input current.

This paper is to investigate the dispersion relation and decay rate of plasmon modes in a double layer system made of monolayer graphene (MLG) and infinite GaAs quantum well at finite temperature within the generalized random-phase-approximation and taking into account the 2DEG layer-thickness and the inhomogeneity of the background dielectric. Calculations demonstrate that when the quantum well width increases, the acoustic (AC) plasmon frequency decreases dramatically, but the optical (OP) one seems unchanged. In addition, the results also illustrate that the temperature and separated distance affect significantly both AC and OP plasmon modes of the system. Finally, the dielectric of the background acts strongly on the OP plasmon curve while carrier density in two layers and exchange-correlation effects only lead to remarkable changes for the acoustic one.