Modern Physics Letters B

The proposed quantum hash function (QHF) based on the discrete-time quantum walk (DTQW) structure requires enlarging the coin state space and the preparation of continuous quantum states is less difficult. Hence, a new construction method of QHF is proposed based on the continuous-time quantum walk (CTQW) of the one-dimensional (1D) lattice with boundary constraints and without additional coin space. In the scheme, the input of the QHF is an arbitrary binary string message which is used to control the selected Hamiltonian of CTQW at each time interval, and the output of the QHF is the final probability distribution of CTQW. Under the same computing environment, simulation and analysis indicate that our QHF can satisfy the same security requirements such as sensitivity, diffusion and confusion, collision, birthday attack, but the collision rate is reduced by 40% without reducing effectiveness.

The telecommunications revolution finds its foundation thanks to new service offerings including voice, images, security of computer data and much more. Thereby, telecommunications can be defined as the transmission of information at a distance using electronic, computer, wired, optical or electromagnetic technologies. At an expense of these characteristics, this paper explores the dynamics of various travelingwaves, through telecommunications systems. In this perspective, we use a (2+1)-dimensional nonlinear transmission line equation, by solving it analytically using a novel developed techniques: The improved Sardar-subequation. As a result, we discover several novel voltage characteristics such as bright, trigonometric, exponential and dark function solutions. Using certain appropriate values, we provide several different surfaces of the solutions produced in this work. These findings will be essential in the telecommunications system used to represent wave propagations.

In order to further reveal the law and characteristics of on-ramp traffic flow into the main line of expressway road and make up for the deficiency of traditional inflow model which cannot evaluate the state of merging area, the coupling theory in physics was introduced. First of all, “gap acceptance” model was adopted to describe the operation law of merging area, and the relationship between important parameters such as flow rate and headway was analyzed by using discrete probability function. Second, coupling degree and coupling coordination degree were put forward, after analyzing the characteristic under the premise of the merging area, using a large amount of measured data regression analysis of the traffic, location speed and the headway of parameters in the coupling. The coupling theory was modified, the coupling function evaluation model of confluence area was established, and the interaction and influence between main line and ramp system were quantitatively analyzed and evaluated. Finally, the model is verified by the actual observation data of Shanghai expressway. The results indicate that in the early peak period, the coupling coordination degree is about 0.36 and 0.4, which is in a moderate coordination stage. During the peak flow period, the coupling coordination degree is only 0.28, which is in a low degree of coordination coupling and the system is relatively disordered. In nonpeak hours, the coupling coordination degree is around 0.83, which is in an extremely coordinated state. The error between the flow calculated by the coupling theory and the data observed in the field is generally 4.2%–12.8%, which indicates that the results of the running status evaluation of merging area by using this model are reliable.

This study investigates thin film’s drainage and lifting of a steady, non-isothermal-modified second-grade incompressible fluid. An approximate analytical technique The homotopy analysis method (HAM) is used to solve the developed governing equations for velocity and temperature fields together with boundary conditions. The expressions for velocity profile, average velocity, temperature distribution, shear stress, and volume flow rate are provided explicitly. The flow of the thin film is found to be substantially dependent on the flow behavior index $m$, magnetic field parameter, dimensionless numbers say stock number $S_t$, and Brinkman number $B_r$. The impact of the above-involved parameters on the fluid’s temperature and velocity is depicted numerically as well as graphically.

Quantum steganography is a technology which can hide information effectively for achieving copyright protection. In this paper, a quantum steganography scheme using quantum wavelet transform and the novel enhanced quantum representation for quantum image is proposed, and this scheme can embed the secret text of size $2^{n-2}\times 2^{n-2}$ into a $2^n\times 2^n$ gray-scale carrier image. In the scrambling operation, the text is scrambled by the scrambling circuit including bit-reverse, quantum equal and CNOT gate to improve its security. Before embedding, the carrier image is first transformed by 1-level quantum Haar wavelet transform, and then its low-frequency part is divided into blocks. The simulation results suggest that the proposed scheme has good performance in visual quality and robustness. Finally, through the analysis of circuit complexity, the scheme has low complexity O(n).

The recently emerged data-driven dynamic mode decomposition (DMD) method was employed to investigate the free surface sloshing dynamics of a partially filled rigid tank excited by horizontal harmonic motions. The volume of fluid algorithm was adopted for liquid–gas free surface tracking, and DMD was utilized for decomposition with physical interpretations of the DMD modes and the eigenvalues. Our results demonstrate that DMD works well for both data reconstruction and future-state prediction in terms of either free surface profiles or the sloshing pressure exerted on the rigid wall. DMD presents an efficient and versatile approach for accelerated reduced-order modeling and future-state forecasting. Our efforts provide the first reference on use of DMD for free surface sloshing problems to the best knowledge of the authors. We publicly share our data and codes for all the implementation.

Carbon nanotubes (CNTs) are widely used in high-quality and high-performance nanoscale devices. Using first-principles calculations, we studied the interaction at the interface between parallel CNTs with different electrical properties under applied transverse electric fields. Typical metallic armchairs (6,6) and semiconducting zigzag (10,0) CNTs were considered. The effect of axial moving of one of the CNTs on the interface electronic structure and interaction energy for different interface types was analyzed. Our calculations revealed that interfacial adhesion of CNTs increased with the increase of the external electric field. At this, the interface charge redistribution for (6,6) and (10,0) CNTs showed different polarization responses. By analyzing the density of states (DOS), a correlation between the semiconductor-to-metal transition in parallel (10,0) CNTs and interface interaction under applied external electric field was demonstrated. Obtained results provide a theoretical background for the application of the adhesion properties of CNTs in future nanoscale devices.

In this study, by using the Corning 1737 glass as a substrate and an e-beam system, the optical properties of the deposit MgF₂ and Nb₂O₅ single-layer film were investigated in terms of extinction coefficients ($k$ values) and refractive indices ($n$ values). The equation $d=\lambda$/(4$n)$ was used to calculate the thickness ($d)$ of 1/4 wavelength ($\lambda )$ for each layer of MgF₂ and Nb₂O₅ layer in the MgF₂–Nb₂O₅ bilayer films of the designed distributed Bragg reflectors (DBRs) with a reflective wavelength at blue light ($\sim$450 nm). Each pair of MgF₂–Nb₂O₅ bilayer film was defined as a period, and the glass substrates were used to deposit the films with two, four, and six periods for the fabrication of the DBRs. The field emission scanning electron microscope equipped with a focused ion beam was used to measure the thickness of each MgF₂–Nb₂O₅ layer in the DBRs with different periods. The measured maximum reflective ratios were compared with Sheppard’s approximate equation, which calculates only the maximum reflective ratio at a specific wavelength. We would show that the measured results of the fabricated DBRs matched the results simulated using Sheppard’s approximate equation.

BaTiO₃ (BTO) is considered the most commonly used ceramic material in multilayer ceramic capacitors due to its desirable dielectric properties. Considering that the miniaturization of electronic devices represents an expanding field of research, modification of BTO has been performed to increase dielectric constant and DC bias characteristic/sensitivity. This research presents the effect of N₂ and air atmospheres on morphological and dielectric properties of BTO nanoparticles modified with organometallic salt at sintering temperatures of $1200^{\circ }$C, $1250^{\circ }$C, $1300^{\circ }$C, and $1350^{\circ }$C. Measured dielectric constants were up to 35,000, with achieved very high values in both atmospheres. Field emission scanning electron microscopy (FESEM) was used for morphological characterization, revealing a porous structure in all the samples. The software image analysis of FESEM images showed a connection between particle and pore size distribution, as well as porosity. Based on the data from the image analysis, the prediction of dielectric properties in relation to morphology indicated that yttrium-based organometallic salt reduced oxygen vacancy generation in N₂ atmosphere. DC bias sensitivity measurements showed that samples with higher dielectric constant had more pronounced sensitivity to voltage change, but most of the samples were stable up to 100 V, making our modified BTO a promising candidate for capacitors.

In this paper, the technique of weak measurement is employed in order to enhance the fidelity of joint remote state preparation (JRSP) protocol under decoherence. We design a quantum circuit of joint remote preparation of a single-qubit state through a GHZ state. Then, we analytically derive the average fidelity of the JRSP protocol under four types of noise usually encountered in real-world implementations of quantum communication protocols, i.e. the phase-flip, depolarizing, amplitude-damping and bit-flip noise. Our study shows that the application of weak measurement and measurement reversal could enhance the average fidelity of the JRSP process under the influence of phase-flip, depolarizing, amplitude-damping noise for most values of the decoherence parameters. If the JRSP process suffers from the bit-flip noise, the weak measurement technique is not useful for increasing the average fidelity.

Based on the density functional theory, the first-principles method had been used to calculate the binding energy, the charge density of the interface, Mulliken population, density of states, band structure and phonon dispersion analysis of Co atom point defects on the W-terminated surface and C-terminated surface of the WC–Co/Diamond film-base interface. The results showed that the binding energy of W-GD, W-VD, W-SD sites on the W termination surface with WC–Co/Diamond interface was gradually weakened. And the binding energy of C-GD, C-SD, C-VD sites on the C termination surface was the same as the former. From the charge density, Co atom on the W-terminated surface of WC(100) had a stronger influence on the film-base interface than the C-terminated surface. From the analysis of the Mulliken population, the ability of Co to transfer charge on W-terminated surface was stronger than C-terminated surface. According to the density of states analysis, the Fermi level state density of the W terminal surface was higher than that of the C terminal surface and the activity of the W terminal surface was higher than that of the C terminal surface. Through the analysis of the electronic energy band structure, the system indicated significant metallicity. The phonon spectrum showed that the presence of Co atoms on the W-terminated surface and C-terminated surface of the WC–Co/Diamond film-base interface is stable.

In this paper, modified equal width Burgers’ equation has been investigated with the aid of unified method and bifurcation. This model has many applications in long wave transmission with dispersion and dissipation in nonlinear medium. The applied technique is efficient to retrieve exact solutions and their dynamic behaviors. The obtained solutions are polynomial and rational function solutions. The behavior of dynamical planer system has been analyzed by assigning different values to the parameters, also each possible case has been shown as phase portraits in this research paper. The estimated solutions demonstrate that the proposed approaches are simple, practical, and promising for investigating further equal width equation’s soliton wave solutions and phase portraits.