International Journal of Theoretical Physics最新文献

In this study, we focus on the stochastic pure-cubic optical solitons of the nonlinear Schrödinger equation, characterized by a parabolic law of nonlinearity. The nonlinear Schrödinger equation models are crucial for simulating pulse propagation in optical fibers especially ultrashort pulses. To obtain optical soliton solutions, we employ the effective and well-known the new Kudryashov and the generalized Kudryashov methods. Through these methods, we successfully derive dark, bright, and singular optical soliton solutions. Our findings are illustrated with 2D and 3D graphics for clarity. A significant aspect of our study is the inclusion of stochasticity in the model. We specifically examine the impact of white noise on the solutions. This effect is detailed in the results section, with corresponding graphs. Throughout our research, we did not encounter any restrictive factors that hindered access to the results. Ultimately, considering the growing number of studies on optical fibers, our work stands out by being the first to obtain optical solutions for this specific model and by investigating the influence of stochastic theories on wave behavior.

In this manuscript, we have continued the work of Herrera et al. (Gen. Relativ. Gravit. 44, 1143, 2012) to investigate the instability of non-static spheres supported by anisotropic matter configuration in the background of D-dimensional Einstein gravity. For this purpose, we assume that our relativistic sphere undergoes adiabatic evolution with a vanishing expansion scalar condition. We compute gravitational field equations, conservation equations, and junction conditions in D-dimensional Einstein theory. After considering the evolution of the systems under an expansion-free background, some significant constraints are established by using a perturbation scheme. This leads us to develop the dynamical instability of expansion-free anisotropic fluid spheres in the Newtonian (N) and Post-Newtonian (PN) domains. After focusing on the N and PN eras, our study reveals that the adiabatic index ((Gamma )), does not contribute to the instability ranges in these domains. Instead, these ranges are being determined solely by the anisotropy of fluid pressure, D-dimensional Einstein gravity parameter, and the radial energy density profile.

In this study, we present an amalgamation of solitary wave solutions for the fractional coupled Drinfeld-Sokolov-Wilson (FCDSW) equations, a versatile mathematical model with significant applications in fluid dynamics, plasma physics, and nonlinear dynamics. By leveraging the two recently developed computational approaches, namely the modified Sardar sub-equation (MSSE) method and the improved (mathbb {F})- expansion method, we manifested the novel soliton solutions in the form of dark, dark-bright, bright-dark, singular, periodic, exponential, and rational forms. Furthermore, we also extracted W-shape, V-shape, mixed trigonometric, and hyperbolic soliton wave solutions, which are not reported in previously. Also, the modulation instability (MI) of the proposed model is also examined. To further understand the dynamics of the FCDSW equations, we conducted a detailed bifurcation analysis to investigate the bifurcation events exhibited by these equations. A sensitivity analysis was also performed to assess the model’s robustness against variations in initial conditions and parameters, offering valuable insights into the system’s susceptibility to perturbations. We proved the effectiveness of our suggested techniques in the analysis of the FCDSW equations using analytical tools and numerical simulations. Our results provide new insights into the behavior and solutions of the FCDSW equations and enhance the mathematical tools for investigating nonlinear partial differential equations (NLPDEs). These findings have potential applications in fields like fluid flow modeling, wave propagation in plasmas, and the study of nonlinear optical phenomena in physics and applied mathematics.

Quantum visual secret sharing scheme combines the traditional visual secret sharing scheme with quantum properties to improve the security of secret information. However, all existing quantum visual secret sharing schemes encode a single pixel as a quantum superposition state. Each pixel requires n qubits for encoding. The number of qubits required grows proportionally to the number of pixels, which is unfavorable when the secret image is large. To reduce the number of qubits used, we propose a (n, n)-threshold quantum visual secret sharing scheme based on position superposition. In the secret sharing phase, the position and the encoded color corresponding to the position of the image are encoded as a quantum superposition state simultaneously. The whole secret image is encoded only once instead of encoding individual pixels. Only (varvec{2m+n}) qubits are required for a secret image of size (varvec{2^m times 2^m}). Then, the qubits encoding the position and the color of the secret image are distributed to n participants. In the recovery phase, n participants work together to recover the secret image by a quantum XOR operation on the qubits encoding the color. Simulations have been carried out to verify the practical feasibility of this scheme. Our scheme reduces the number of qubits used in the secret sharing process compared to previous quantum visual secret sharing schemes. In addition, there is no need to design the codebook in advance and the secret image can be fully recovered.

Within the framework of quantum information theory, the performance of conventional 2-D techniques is often unsatisfactory for the study of Bell states that hold a unique status as maximally entangled states. Therefore, 3-D approaches are increasingly employed to achieve more accurate and detailed analysis, offering improved performance and insights in complex scenarios. Among the diverse background of mixed two-qubit states, certain configurations exhibit unique quantum correlations that harness advanced quantum information processing tasks such as Bell diagonal states. Although, these states may appear superficially simple and exhibit a rich spectrum of correlations. The present research employs a methodology that involves a convex combination of distinct Bell states to generate the entire class of Bell diagonal states. This work explores the time evolution of Bell diagonal states, when exposed to various quantum channels and investigates the dynamics of quantum correlations such as entanglement, discord, and state of separability. Finally, the behaviour of Bell diagonal states is analysed and results are compared between theory and practice. A threedimensional visual approach is used to illustrate a deeper understanding of various quantum features and dynamic behaviour of the Bell diagonal states.

I discuss singular loci in the phase spaces of theories which lack globally well-defined numbers of dynamical modes. This is a topic which appears quite often in the recent literature on modified gravity. In particular, there were discussions about (R^2) gravity around Minkowski space. It is a relatively simple case, and still there were some confusions. It clearly shows that one should be very accurate when trying to understand a potentially problematic theory through perturbations around a simply looking background. At the same time, many modern teleparallel approaches are laden with even more severe issues. Therefore, it is a topic which is certainly worth carefully thinking about.

The standard model Higgs boson has various decay modes, some of which have been measured in the CMS and ATLAS experiments, located at the Large Hadron Collider at CERN. This paper, calculates the decay of the standard model Higgs boson into (D^{*pm }) meson through the mechanism direct fragmentation. In this approach, the Higgs boson, first decays into (cbar{c}) and (bbar{b}) pairs, and then the heavy quarks fragment directly into (D^{*pm }) meson. The branching ratios of the SM Higgs boson into (D^{*pm }) meson have been calculated by considering NLO and NNLO corrections in the fragmentation functions of (D^{*pm }).

This paper focuses on obtaining exact solutions of nonlinear Akbota equation through the application of the modified Khater method and Sardar sub-equation method. Renowned as one of the latest and precise analytical schemes for nonlinear evolution equations, this method has proven its efficacy by generating diverse solutions for the model under consideration. The equation is crucial in the study of optical solitons, which are stable pulses of light that maintain their shape over long distances. The Akbota equation helps in understanding the behavior and stability of these solitons. The governing equation undergoes transformation into an ordinary differential equation through a well-suited wave transformation. This analytical simplification paves the way for the derivation of trigonometric, hyperbolic, and rational solutions through the proposed methods. To illuminate the physical behavior of the model, the study presents graphical plots of the selected solutions of Khater and Sardar sub-equation method. This visual representation, achieved by selecting appropriate values for arbitrary parameters, enhances the understanding of the system’s dynamics. All calculations in this study are meticulously conducted using the Mathematica and Maple software, ensuring accuracy and reliability in the analysis of the obtained solution. Furthermore we investigate the sensitivity analysis of the dynamical system.

Designing efficient techniques to search over encrypted data space has always been an intriguing security challenge, although many solutions based on classical searching methods have been proposed. Grover’s algorithm, a quantum counterpart of searching algorithms, has proven to provide quadratic speedup over any classical search technique on an unsorted database. However, this algorithm is unable to search over encrypted data space. This study proposed an extension of Grover’s algorithm to enable search over encrypted dataspace, allowing clients with limited-capability quantum resources to delegate complex search operations to an untrusted server. The blindness of data in this protocol is achieved by encrypting qubits using Pauli’s rotation gates that maximally mix the outgoing states. The empirical estimation of the overhead of the computation due to the introduction of this technique has been analyzed. This estimate has been used for comparative analysis, showing the efficiency of the proposed protocol. A practical application of the proposed searchable encryption technique has been utilized to estimate the increase in resources needed to carry out a brute-force attack on AES encryption using secure Grover’s algorithm. Furthermore, an extensive experimental analysis of the effect of noise has been studied using four different noise models: amplitude damping, phase damping, depolarizing noise, and bit-flip noise. The investigation provided useful insight into the behavior of the proposed algorithm under noisy conditions and also estimated the tolerance thresholds of the proposed algorithm under different noise models.

We investigate the thermodynamic properties of a five-dimensional Reissner-Nordström black hole within the framework of Einstein-Yang-Mills gravity, employing the higher-dimensional Wu-Yang Ansatz. By incorporating quantum fluctuations, we examine the behavior of thermodynamic potentials, including internal energy, free energy, Gibbs free energy, and enthalpy. Our analysis reveals that quantum effects are predominantly influential near the event horizon, with negligible impact on larger black holes. Notably, Gibbs free energy emerges as a promising candidate for modeling the black hole as a heat engine. Furthermore, specific heat analysis indicates a second-order phase transition for the system under consideration.