International Journal of Modern Physics B

A preliminary overview of measurement-based quantum computation (QC) in the setting of symmetry and topological (TOP) phases of quantum matter is given. The underlying mechanism for universal QC by teleportation or symmetry are analyzed, with the emphasis on the relation with tensor-network states in the presence of various symmetries. Perspectives are also given for the role of symmetry and phases of quantum matter in measurement-based QC and fault tolerance.

An appropriate parking supply in cities should not only satisfy car travel demands but also restrict the number of car trips to reduce congestion and carbon emissions on road networks. This paper analyzes when car owners will abandon car driving based on a survey of the parking experiences of people in Changsha, China. The results indicate that car owners are most likely to abandon driving when the total time expenditure (including the search time and walking time) exceeds 20 min or the walking distance between a car park and a destination exceeds 400 m. In addition, car owners’ decisions regarding different trip purposes (commuting, business, hospital trips, shopping and entertainment activities) are compared. Multinomial logistic regression models and correspondence analysis methods are applied to identify the factors influencing car owners’ decisions. The results show that public transport and the parking pricing level near work places have a substantial impact on people’s decisions: people will more readily abandon driving when the travel time of public transit decreases; age, occupation and annual household income have a significant influence on people’s parking condition preferences for business trips and trips to hospitals; and the factor that primarily influences the mode choice for shopping and entertainment trips is annual household income. The outcome of this study can provide a basis for determining the optimal parking supply level and facilitate the realization of sustainable transportation.

We have investigated the crystal structure of strongly anisotropic semiconductor TlInSe₂ by neutron diffraction method under high pressure upto P = 3.3 GPa. It was shown that the tetragonal phase of TlInSe₂ crystal (the space group I4/mcm) is stable in the whole investigated range of pressure. The lattice parameters dependence of the pressure and the unit cell volume are obtained, the linear coefficients of compressibility and the bulk moduli are calculated. At the low pressure, obtained value of compressibility for the lattice parameter a is k${}_a$ = 14.23 × 10${}^{-3}$ GPa${}^{-1}$ and for c is k${}_c$ = 5.93 × 10${}^{-3}$ GPa${}^{-1}$. Obtained values for bulk modulus B₀ and its pressure derivative B${}^{\prime }$ in tetragonal phase are 30(7) GPa and 4(1), respectively.

A user click fraud detection method based on Top-Rank-k frequent pattern mining algorithm is presented to solve the click fraud problem appearing in current online advertising. Firstly, this method combines the click frequency of event samples, calculates the real evaluation score of click stream, and the click stream density function and evaluation score expression under multi-dimensional variables, and further obtains the time complexity of the next user’s click fraud process. Secondly, according to the Top-Rank-k frequent pattern, the process of click fraud detection algorithm is designed, and the click fraud user is analyzed and obtained. The results show that this method has good efficiency and correctness, and is superior to other similar algorithms.

Current commercially available rechargeable Li-ion batteries, for example LiCoO₂, are working mostly in the 4 V regime. One often suggested possibility to improve the effectivity of Li-ion batteries are the creation of the 5 V cathode materials. We performed quantum mechanical calculations on the average battery voltage for the Li₂Co${}_x$Mn${}_{4-x}$O₈ (x = 0, 1, 2, 3 and 4) cathode materials by means of the WIEN2k computer program package. The calculated average battery voltages for x = 0, 1, 2, 3 and 4 are equal to 3.95, 5, 4.47, 4.19 and 3.99 V. Our ab initio calculation results are compared with the available experimental data for x = 0, 1, 2 and 4 which are equal to 4, 5, 5 and 4 V. Thereby, for the Li₂Co₁Mn₃O₈ battery cathode material, our calculated average battery voltage around 5 V is in perfect agreement with the experimentally available battery voltage value of 5 Volt. Nevertheless, our calculated average battery voltage is underestimated (4.47 V) for the Li₂Co₂Mn₂O₈ cathode material, which also experimentally exhibits the 5 V voltage.

To research the piezoresistive properties of SiC thin films, a testing structure consisting of a cantilever beam, SiC thin films piezoresistors and a Cr/Pt electrode is proposed in this paper. The chips of testing structure were fabricated by micro-electro-mechanical system (MEMS) technology on a silicon wafer with $〈$100$〉$ orientation, in which SiC thin films were deposited by using radio-frequency (13.56 MHz) magnetron sputtering method. The effect of sputtering power, annealing temperature and time on the microstructure and morphology of the SiC thin films were investigated by the X-ray diffraction (XRD) and scanning electron microscopy (SEM). It indicates that a good continuity and uniform particles on the SiC thin film surface can be achieved at sputtering power of 160 W after annealing. To verify the existence of Si–C bonds in the thin films, X-ray photoelectron spectroscopy (XPS) was used. Meanwhile, the piezoresistive properties of SiC thin films piezoresistors were measured using the proposed cantilever beam. The test result shows that it is possible to achieve a gauge factor of 35.1.

This study proposes a new nonlane-based continuum model derived from a two-sided lateral gap-following theory using the relation between microscopic and macroscopic variables. The model considers the effect of lateral gaps of the leading vehicles available on both sides of the following vehicle in multilane scenario. Linear stability analysis is performed to establish the neutral stability condition for the stable traffic flow. Nonlinear analysis is carried out at neutral stability line to derive the KdV–Berger equation, which describes density wave propagation. For that, one of the traveling wave solutions is also obtained. Numerical simulation results show that the two-sided lateral gap in the model improves the stability of the traffic flow by suppressing the traffic jams even at high-density conditions. The results implies that the proposed model is successful in replicating the properties of actual traffic jams in nonlane-based traffic environment.

Magneto tunable left-handed material (LHM) which acts as a composite system has been theoretically demonstrated. The variation of the real and imaginary parts of the effective refractive index of the system is studied. The resonance that occurs in these studies are analyzed. The variation of impedance, reflectivity, absorptivity with frequency of the composite system was observed. The changes in resonance frequency with applied magnetic field are investigated. It is found that the resonance frequency increases with applied magnetic field.

Based on Monte Carlo simulation and fast Fourier transformation and micromagnetism (FFTM) method, magnetic properties of cobalt (Co) nanorings with different asymmetry have been studied. Spin configurations, magnetization hysteresis loops, as well as remanence of the Co nanoring systems with different asymmetry were calculated to demonstrate the difference in magnetization dynamics processes. The calculated results indicate that asymmetry has an important effect on magnetic properties of the asymmetric Co nanorings. It is found that with decreasing asymmetry the hysteresis loops of asymmetric Co nanorings drop and form new step, and then form multi-steps or double-step, which can be explained as the change of spin configurations. The remanence of the systems decline in the twists and turns, which shows a local minimum as a = b, and at the same time, the remanence with $𝜃$ periodically changes. Spin configurations and shape of the system account for these results.

LAP crystal is an excellent nonlinear optical material and it has some unexplained specificities, which makes the interaction between groups in molecule received much attention. In this paper, the first-principles calculations are performed to investigate the intergroup interactions by the electronic structure and optical properties of LAP crystal. The energy gap of LAP crystal is 5.02 eV, indicating that the electronic transition is easier than KDP crystal. The strong electronic interaction between the carboxyl, phosphate and guanidine groups is found. In addition, since the LAP molecule has the greatest dipole in [010] direction and the electronic transitions are most likely to occur between the carboxyl group, phosphate and guanidine groups located on both ends of the molecule along [010] direction, the LAP crystal shows specific optical properties in this direction. The results reveal the correlations between the optical properties and the intergroup interactions of LAP crystal.

Aiming to solve the problem that it is difficult to extract large parameter signals from a strong noise background, a novel method of large parameter stochastic resonance (SR) induced by a secondary signal is proposed. The SR mechanism of high-frequency signals is expounded by analyzing the density distribution curve. High-frequency signals are converted to low-frequency signals using the scale transformation method, and then large-parameter SR is induced by the secondary signal. Ultimately, the method is applied to the feature extraction of mechanical faults. Simulation and experimental results indicate that (i) the effect of SR induced by the secondary signal is significantly enhanced when the frequency of the secondary signal is twice that of the signals to be detected after the scale transformation; (ii) when the frequency of secondary signal is twice the maximum frequency of the signals to be detected after the scale transformation, choosing an appropriate amplitude of secondary signal can alleviate the problem that the noise energy is excessively concentrated in the low-frequency channel with regard to the extraction of two-frequency or three-frequency high-frequency signals; and (iii) by adding the secondary signal to the engineering example, the fault power spectrum value of system output is 101% higher than that without the secondary signal.

The effect of germanium doping on the structural, magnetic, elastic and optical properties of the LiMgPdSn-type CoFeZrSi${}_{1-x}$Ge${}_x$ alloys is predicted by utilizing ab initio density functional theory (DFT) with the generalized gradient approximation (GGA) and the electronic properties of the materials are investigated by using the generalized gradient approximation plus Hubbard coefficient (GGA + U). The estimated elevated lattice constant of CoFeZrGe compound agrees with existing theoretical data. The optimized lattice constants of CoFeZrSi${}_{1-x}$Ge${}_x$(x = 0, 0.25, 0.50, 0.75) are 5.9022, 5.9631, 5.9752 and 5.9973 Å, respectively. These have been investigated for the very first time. The elastic symmetry (C${}_{11}$, C${}_{12}$, C${}_{13}$, C${}_{33}$, C${}_{44}$ and C${}_{66}$), bulk modulus, shear modulus, Poisson’s ratio, anisotropy and Pugh ratio (B/G) are predicted and discussed. The calculation of band structure and density of states reveal that the materials considered have half-metallic behavior with 100% spin-polarization. The calculated magnetic moments of CoFeZrSi${}_{1-x}$Ge${}_x$ are 0.99, 1.06, 1.02, 1.00 and 1.01 ${\mu }_{\mathrm{\text{B}}}$, respectively, and agree with the SP rule, M${}_t$ = N${}_V$ − 24. The analysis of the elastic moduli indicates that the compounds are mechanically stable with a ductile nature. The CoFeZrSi${}_{0.5}$Ge${}_{0.5}$ alloy is stiffer than the other compounds considered. Moreover, the dielectric functions, optical conductivity, reflectivity and absorption coefficient of CoFeZrSi${}_{1-x}$Ge${}_x$ compounds are predicted by using complex dielectric functions.

We introduce a method that combines the unscented Kalman filter (UKF) and the adaptive lag synchronization (ALS) to estimate the unknown parameters of a neuron model with seizure-like activity using only the heavily noise-corrupted time series of membrane potentials. Although both UKF and ALS are able to estimate the parameters, UKF performs worse when the number of unknown parameters increases, while ALS requires system states that cannot be measured in practice. Therefore, we incorporate UKF as an observer of the unmeasured states into ALS method to estimate multiple parameters. The effectiveness of the combined method is guaranteed by Lyapunov stability theorem and Barbalat’s lemma in theory. Numerical simulations demonstrate that, when two parameters are estimated simultaneously, the combined approach has better performance and higher accuracy than only using UKF or ALS method. This exploration of the proposed approach may play an important role in studying new treatments in seizure control.

Synchronous oscillations in certain frequencies of the sub-thalamic nucleus (STN) neurons are closely related to the physical symptoms of Parkinson’s disease (PD). Recent results have highlighted the importance of calcium channels in the synchronization properties and regulation of STN neurons. In this paper, a novel hybrid neuron model which can capture the electrophysiological signature of neurons with low or high density of calcium channels is used to explore the synchronization propensity and regulation by firing frequencies of neurons. Numerical simulations show that the synchronization propensity of networks consisting of the novel hybrid neurons is quite distinguishing in low and high calcium conductance modes, especially, the synchronization can be differentially modulated by network frequencies in the two modes. By analyzing the firing frequency and phase response curve of the individual neuron, we find that a single parameter of the hybrid neuron, which is a direct image of the calcium conductance, is crucial in determining the excitability and response properties of the neuron. Different phase response properties of single neurons in different calcium conductance modes lead to network synchronization discrepancies.