International Journal of Theoretical Physics最新文献

{"title":"Principles and Architectures of Coherent Ising Machines: Optical Networks for Optimization and Quantum Neural Computing","authors":"Vahid Esrafilian,&nbsp;Bahram Abedi Ravan,&nbsp;Alireza Javadi,&nbsp;Hamidreza Daniali","doi":"10.1007/s10773-026-06497-w","DOIUrl":"10.1007/s10773-026-06497-w","url":null,"abstract":"<div><p>Coherent Ising machines (CIMs) are open-dissipative optical or optoelectronic networks designed to find low-energy configurations of the Ising Hamiltonian. In the optical quantum neural network (QNN) program developed around degenerate optical parametric oscillators (DOPOs), each spin is encoded in one of two phase states of a parametric oscillator, while optical coupling, measurement feedback, or electronic feedback implements the problem-dependent synaptic matrix. This review explains CIMs from four connected viewpoints: combinatorial optimization, optical neural networks, quantum optics, and nonequilibrium dynamical systems. We derive the Max-Cut-to-Ising mapping, the squeezing and threshold physics of a degenerate optical parametric amplifier/oscillator, mean-field and stochastic equations for DOPO networks, and the measurement-feedback master-equation picture. We also discuss the physical roles of squeezed vacuum, anti-squeezed quadrature noise, quantum correlations, contextual measurement, bifurcation, gain saturation, bosonic final-state stimulation, and quantum-to-classical crossover. Finally, we review delay-line and measurement-feedback architectures, experimental milestones from few-spin demonstrations to 100,000-spin machines, benchmark issues, limitations, and prospects for future quantum-optical and neuromorphic optimization hardware.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 10","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149132266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Non-singular Durgapal-Fuloria Gravastar Solutions in (f(R,L_{m},T)) Gravity","authors":"Bharat Singh,&nbsp;S. Surendra Singh","doi":"10.1007/s10773-026-06493-0","DOIUrl":"10.1007/s10773-026-06493-0","url":null,"abstract":"<div><p>The gravastar (gravitational vacuum star) has been introduced as a viable alternative to black hole (BH), with its foundational concept developed by Pawel Mazur and Mottola. This study explores a non-minimal matter-geometry coupling given by <span>(f(R,L_{m}, T) = R+alpha T L_{m})</span>, and constructs a gravastar model in the context of modified <span>(f(R,L_{m},T))</span> gravity. Unlike earlier investigations, the present work emphasizes the impact of the trace-matter interaction on the physical viability and stability of the gravastar configuration. As proposed by Mazur and Mottola, the gravastar configuration is divided into three separate region, with each region governed by its own distinct equation of state. For the interior sector, we adopt a spacetime description corresponding to a vacuum like fluid with <span>(p= -rho )</span>. Within the dark sector, adopting the EoS <span>(rho = p)</span> characteristic of an ultra-relativistic fluid leads to a negative energy density, which generates a repulsive gravitational effect acting on the neighboring thin shell. A detailed quantitative investigation of the proper length, total energy, energy density, and entropy is carried out. For the vacuum exterior of the garvastar, the Schwarzschild metric spacetime is considered. Furthermore, we investigate the interface between the interior and exterior spacetime region of the gravastar by employing relevant junction conditions.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 10","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149133214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preface to the Special Issue “Quantum Structures 2024”","authors":"Tomas Veloz","doi":"10.1007/s10773-026-06492-1","DOIUrl":"10.1007/s10773-026-06492-1","url":null,"abstract":"","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 10","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149133181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bifurcation Analysis of Dust Acoustic Waves in a Negatively Charged Dust Plasma With Regularized ((kappa ))-distributed Electrons-ions","authors":"R. A. Shahein,&nbsp;A. A. Al-Raddadi","doi":"10.1007/s10773-026-06491-2","DOIUrl":"10.1007/s10773-026-06491-2","url":null,"abstract":"<div><p>A precise theoretical consideration of dust acoustic solitary (DAS) waves in a negative dust plasma with regularized <span>(kappa )</span>-distributed (RKD) electrons and ions is presented. The linear and nonlinear analyses are studied. The KdV equation appropriate for depicting DAS waves is derived. The bifurcation concept of planar dynamical system (PDS) and Sagdeev potential analysis are used. The Jacobi elliptic function expansion approach for solving the KdVE is applied, which yields three analytical solutions to the solitary waves based on the system parameters. The DAWs are investigated by using four techniques to get a comprehensive awareness. It is found that such potential demonstrates a rarefactive solitary wave in the mesosphere zone. The effects of plasma parameters (such as electron temperature <span>(T_e)</span>, cutoff <span>(delta )</span>, and electron density) on the DAWs are illustrated in 2D-3D, contour plots and phase portraits. Also, we introduced a novel comparison of the RKD and the standard <span>(kappa )</span> distribution (SKD) in DAWs, where we extracted that the velocity of DAWs in the case of SKD is faster than in the case of RKD. The results from this work are expected to contribute to the in-depth understanding of the instability and propagation of the nonlinear DAWs in the Earth’s mesosphere zone and in the astrophysical plasma in general.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 10","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Emergence of Symmetry in a System of Distinguishable but Identical Particles","authors":"Allan Tameshtit","doi":"10.1007/s10773-026-06390-6","DOIUrl":"10.1007/s10773-026-06390-6","url":null,"abstract":"<div><p>Instead of the conventional construction of symmetric and antisymmetric states by abruptly projecting with the symmetrizer or antisymmetrizer, this paper investigates rapid but continuous symmetrization via environment-induced decoherence. Density operators are transformed to a symmetric observable via a semigroup map obtained from an interacting Hamiltonian. Likewise, a completely positive dynamical map transforms perfectly asymmetric states to either symmetric or antisymmetric states. The theory is applied to analyse a collision between two identical particles having arbitrary spin and negligible spin interactions. We discuss extensions to larger domains via dynamical maps that are not completely positive.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 10","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Insights in Hybrid-Rayleigh-van der Pol Duffing Oscillator","authors":"Galal M. Moatimid,&nbsp;T. S. Amer,&nbsp;Mona A. A. Mohamed","doi":"10.1007/s10773-026-06488-x","DOIUrl":"10.1007/s10773-026-06488-x","url":null,"abstract":"<div><p>The hybrid Rayleigh–van der Pol–Duffing oscillator combines nonlinear damping and stiffness, facilitating a detailed analysis of dynamic behaviour. It reveals complex phenomena like multi-stability, bifurcations, chaos, and enhanced resonance, making it essential in modelling and controlling nonlinear engineering, mechanical, and electromechanical systems. Therefore, the current work examines this issue and the novelty of it represents in the new methodology in handling this model. An alternative linear ordinary differential equation is derived by means of the non-perturbative approach as the core procedure. Contrary to conventional perturbation methods, the non-perturbative approach does not employ Taylor expansion. The proposed approach is confirmed, highlighting its precision, efficacy, and application. The derived parametric equation is validated by means of Mathematica Software and exhibits substantial agreement with the numerical solution of the original system. In the absence of the external force, the stability analysis of the linear ordinary differential equation is conducted using the compatible nonlinear one. The non-perturbative approach seems to be straightforward, attractive, promising, powerful, and engaging. It can be utilized in various forms of interconnected Dynamical Systems. Furthermore, the system's chaotic behaviour is analysed to understand its dynamics and transition from periodic to chaotic states. Bifurcation diagrams, Poincaré maps, and phase portraits collectively offer a comprehensive depiction of its behaviour across different situations.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 10","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Logarithmic Corrections to Bekenstein-Hawking Entropy and Their Cosmological Implications","authors":"M. Faruk Karabat","doi":"10.1007/s10773-026-06485-0","DOIUrl":"10.1007/s10773-026-06485-0","url":null,"abstract":"<div><p>The Bekenstein-Hawking entropy, a cornerstone of black hole thermodynamics, is known to acquire logarithmic corrections due to quantum gravity effects. In this study, we explore the cosmological implications of these entropy corrections by deriving a modified continuity equation based on holographic principles and thermodynamic considerations. The resulting equation includes terms proportional to <span>({H}^{3})</span> and <span>({H}^{5})</span>, which alter the evolution of the universe's energy density <span>(rho (a))</span><i>.</i> Our analysis reveals significant modifications to energy density evolution in the late universe. In the matter-dominated era <span>((w=0))</span>, entropic corrections substantially slow energy density dilution compared to the standard <span>(rho propto { a}^{-3})</span> scaling. The radiation-dominated epoch <span>((w=1/3))</span> exhibits alterations in the energy density decay within the mathematical framework, although the present phenomenological approach is restricted to the late universe, where these corrections become significant. During the dark energy-dominated era <span>((w=-1))</span>, the logarithmic entropy correction induces a transient scale-factor dependence of the dark energy density, leading to a temporary departure from the standard <span>(Lambda CDM)</span> behavior at intermediate epochs.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 10","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Soliton Behavior Under Multiplicative White Noise: Analytical and Numerical Insights Using the mKdV Equation","authors":"Gassan AMO Farah,&nbsp;Mehmet Yavuz,&nbsp;Emad A.-B. Abdel-Salam,&nbsp;Ercan Çelik","doi":"10.1007/s10773-026-06468-1","DOIUrl":"10.1007/s10773-026-06468-1","url":null,"abstract":"<div><p>The present study aims to investigate the influence of multiplicative stochastic fluctuations, modelled by a Wiener process, on the dynamics, stability, and interactions of soliton and singular-soliton solutions of the modified Korteweg-de Vries (mKdV) equation. To this end, singular-soliton solutions are derived via Hirota’s bilinear method, thereby establishing an analytical framework for examining the evolution and deformation of solitary structures under stochastic forcing. Mathematically, the main contribution is the rigorous application of an Itô integrating-factor transformation that eliminates the multiplicative noise term, reducing the stochastic problem to a deterministic mKdV equation amenable to exact solution techniques. The dependence of wave behavior on the noise intensity is then examined, and numerical simulations, employing Euler-Maruyama and Milstein schemes with appropriate stability constraints, are conducted to validate the analytical results and to illustrate how variations in noise level modify wave profiles and propagation characteristics through extensive simulations, revealing that increasing noise intensity leads to amplitude attenuation, spatial broadening, and distortion of soliton cores. By combining stochastic modelling, exact solution construction, and computational verification, the study advances understanding of nonlinear dispersive waves in noisy media, with relevance to applications in fluid dynamics, plasma physics, and related fields where random perturbations play a significant role.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 10","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"About the Concept of Entropy for Unstable Quantum States: on the Role of Resonances in Quantum Statistical Mechanics","authors":"O. Civitarese,&nbsp;M. Gadella","doi":"10.1007/s10773-026-06483-2","DOIUrl":"10.1007/s10773-026-06483-2","url":null,"abstract":"<div><p>The standard formalism of quantum statistical mechanics assumes real energy eigenstates belonging to the system under study. This is indeed true when one is working in the Hamiltonian (e.g, Hermitian) representation, in terms of Hermitian operators and wave functions with real energies. Alternatively one may think of representations where the Hamiltonians are non-Hermitian but which could have real eigenvalues under the action of certain symmetries, like PT, although this class of operators do not belong to extensions of the Hilbert space. In other words, PT symmetric non-Hermitian Hamiltonians and those belonging to extensions of the Hilbert space are not the same. Working with Gel’fand triplets allow us to deal with states of complex energy. The existence of unstable states, that is to say states of complex energy like Gamow states, has been demonstrated for a variety of systems, then it is a reasonable question to investigate the consequences upon the conventional formulation of statistical observables in basis where bound states and Gamow’s states belong to the spectrum. Then, if one formulates transition amplitudes, instead of probabilities, in basis with real and complex energy states, one gets mean values which are also complex. Therefore, the conventional interpretation of the entropy, as a purely real component of the free energy, is not longer valid. In order to get a purely real free energy, the imaginary part of the product TS should be equal to the imaginary part of E, being the temperature T real. In this work we shall extend on this notion and advance a physical interpretation of complex values of the entropy by means of some examples consisting of the quantum mechanical treatment of systems which exhibit Gamow’s states in their spectra. The interest in such studies has been raised recently by theoretical analysis of the role of Gamow states on the thermodynamics of black holes, particularly in dealing with the case of Gamow states gravitationally bound to a Reissner-Nordström black hole. Here, we shall analyse the case of a mini-black hole, to illustrate and interpret the role of the real and imaginary parts of thermodynamical potentials like the entropy. The formalism is applicable to a physical system where its energy spectrum, resulting from the treatment of a central potential under confining boundary conditions, exhibits bound states and resonances.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 10","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035017","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structure and Flow Observables in Complementarity Dynamics of Open Two-Qubit Systems","authors":"Matthias Jakob","doi":"10.1007/s10773-026-06486-z","DOIUrl":"10.1007/s10773-026-06486-z","url":null,"abstract":"<div><p>Quantitative complementarity constrains how local predictability, fringe visibility, and bipartite concurrence share an information budget at a given instant, but an instantaneous balance does not by itself identify environmental memory. We therefore distinguish a structure diagnostic from two temporal flow diagnostics for open two-qubit dynamics. The structure distance <span>(Delta _D)</span> measures the largest separation between the complementarity deficit and the global linear entropy along a trajectory. The concurrence-revival flow <span>(N_C)</span> accumulates positive concurrence increments, whereas the budget-recovery flow <span>(N_{-D})</span> accumulates positive increments of the shifted complementarity budget. Local amplitude-damping and dephasing channels, a <span>(31times 61)</span> parameter scan, comparisons with local Breuer–Laine–Piilo trace-distance-backflow proxies, an exact Bell-sector identity, and a general flow bound establish distinct diagnostic roles. The structure distance depends predominantly on state preparation, the concurrence flow selectively records entanglement revivals, and the budget flow responds more broadly and can remain nonzero without trace-distance backflow. The framework is therefore not a new non-Markovianity measure; it provides a reproducible way to separate state-space organization from temporal recovery in complementarity dynamics.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 10","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148987094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}