International Journal of Theoretical Physics最新文献

{"title":"Quantum-State Texture Estimation of Superposition States","authors":"Cheng-Yang Zhang,&nbsp;Zhi-Hua Guo,&nbsp;Huai-Xin Cao","doi":"10.1007/s10773-026-06467-2","DOIUrl":"10.1007/s10773-026-06467-2","url":null,"abstract":"<div><p>Recently, quantum-state texture has attracted increasing attention as a quantum resource with potential applications in quantum information processing. We derive tight lower and upper bounds relating the geometric texture of a superposition of <span>(nge 2)</span> mutually orthogonal pure states to the textures of its constituent states and characterize the corresponding equality conditions. As an application, we determine the temperature-dependent attainable texture range of phase-generalized coherent Gibbs states in arbitrary dimensions. The coherent Gibbs state attains the lower bound at every positive temperature, whereas the upper bound is attained by appropriately choosing the relative phases of the energy-eigenbasis expansion coefficients of the phase-generalized coherent Gibbs state. For equally spaced energy levels, increasing the dimension lowers the scaled temperature at which the upper bound reaches unity, while the lower bound approaches its high-temperature limit of zero more slowly. These results provide a quantitative characterization of geometric texture under superposition and reveal how temperature, dimension and relative phases jointly determine the attainable texture range.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 9","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148926336","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":"An Analytical Solution to the Vacuum Free Boundary Problem of Compressible Navier-Stokes-Korteweg Equations","authors":"Jianwei Dong,&nbsp;Jiaying Liu,&nbsp;Lijun Zhang","doi":"10.1007/s10773-026-06461-8","DOIUrl":"10.1007/s10773-026-06461-8","url":null,"abstract":"<div><p>In this paper, we consider the vacuum free boundary problem of compressible Navier-Stokes-Korteweg equations with spherical symmetry. The capillary coefficient is assumed to be a positive constant and the bulk and shear viscosities are assumed to be power functions of density. By using some ansatzes, we construct a self-similar analytical solution to the problem when both the adiabatic exponent and the power of the functions of viscosities are equal to 3/2. Moreover, we show that the free boundary spreads outward at least sub-linearly in time with the rate of <span>(mathcal {O}((1+t)^{2/3}))</span> and not more than linearly in time for the constructed solution, by using the averaged quantities method. Particularly, with the aid of some inequality techniques, we prove that the free boundary can spreads outward almost linearly in time provided that the capillary coefficient is sufficiently large. This may indicate that the capillary effect can stimulus the expansion of free boundary.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 9","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148926337","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":"Klein–Gordon Oscillator with Linear–Fractional Deformed Mass-Shell Invariants in Doubly Special Relativity","authors":"Abdelmalek Boumali,&nbsp;Nosratollah Jafari","doi":"10.1007/s10773-026-06464-5","DOIUrl":"10.1007/s10773-026-06464-5","url":null,"abstract":"<div><p>We study the Klein–Gordon oscillator in a doubly special relativity framework defined by a linear–fractional deformation of the mass-shell relation. In <span>((1+1))</span> dimensions, the deformation is classified by the timelike, spacelike, or lightlike character of a fixed covector <span>(a_mu )</span>. Using a reverted-product nonminimal coupling, we derive exact energy spectra and stationary states for all three sectors. The timelike and lightlike realizations are isospectral to each other and produce a common Planck-suppressed displacement of the particle and antiparticle branches, thereby breaking the exact <span>(Eleftrightarrow -E)</span> symmetry. The spacelike realization leaves the spectrum unchanged but yields a non-Hermitian, <span>(mathcal{P}mathcal{T})</span>-symmetric spatial operator; an explicit similarity transformation maps it to the Hermitian Klein–Gordon oscillator. We also compare the first-power linear–fractional deformation with the Magueijo–Smolin model and show that the denominator power controls the magnitude of the spectral displacement. These results isolate how the causal class and functional form of the deformation affect relativistic oscillator spectra and states.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 9","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148838386","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":"Operational Recoverability Bounds for Proper-Time Interferometry with Open Quantum Clocks","authors":"Kaixuan Zhao","doi":"10.1007/s10773-026-06421-2","DOIUrl":"10.1007/s10773-026-06421-2","url":null,"abstract":"<div><p>Clock interferometry probes general-relativistic proper-time differences through the entanglement between a particle’s center-of-mass path and its internal degrees of freedom. Existing analyses treat the internal clock as either a closed system or study how environmental noise modifies the interferometric visibility. Here we address a different question: how much of the proper-time-induced visibility loss remains recoverable when the experimentalist is restricted to local unitary control of the internal clock. We model the clock as a two-level system undergoing spontaneous decay while the two arms of a Mach-Zehnder interferometer accumulate different proper times. For a single refocusing pulse that exchanges the internal ground and excited states midway through the evolution, we derive the exact echo visibility by keeping the complete environmental jump structure, including the two-jump history made possible by this pulse. This yields a closed analytic expression for the echo-recovered visibility and a tight phase-maximized envelope for the single-echo protocol. In the absence of environmental coupling, the pulse restores full visibility. With environmental decay, generic proper-time differences leave an echo-recovery deficit, whereas equal proper times retain unit visibility exactly. We also establish the conditions under which a proper-time-parametrized Gorini-Kossakowski-Sudarshan-Lindblad equation is valid by appealing to the local comoving frame and the equivalence principle, distinguishing comoving-bath and laboratory-bath parametrizations. Numerical evaluations of the composed Kraus channel, implemented with QuTiP, agree with the analytic expressions. Experimental estimates for cold-atom and cavity-QED platforms indicate that the irreversible visibility deficit is modest for natural optical linewidths but can be enhanced by longer interrogation times or Purcell-enhanced decay. After calibration of technical contrast losses, the echo-recovery deficit therefore serves as an operational indicator of irreversible environmental decoherence, distinguishing it from the reversible path-clock entanglement of the closed-system proper-time mechanism.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 9","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148838387","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":"An Interpretable Neural Network–Based Symbolic Approach for Exact Soliton Solutions of Nonlinear Evolution Equations","authors":"Ghulam Hussain Tipu,&nbsp;Abdul Mateen","doi":"10.1007/s10773-026-06463-6","DOIUrl":"10.1007/s10773-026-06463-6","url":null,"abstract":"<div><p>In scientific computing, developing solutions that simultaneously ensure accuracy and computational efficiency remains a persistent challenge, motivating the use of neural network (NN)–based approaches. In this study, we employ a sub-equation neural network method (SENNM), which integrates NN models with the sub-equation method to obtain exact analytical solutions of nonlinear partial differential equations (NLPDEs). A key novelty of this method is the introduction of a modified activation function derived from solutions of the Riccati equation, establishing a direct mathematical link between differential equations theory and deep learning. By leveraging the great approximation power of the NNs and the high precision of the symbolic computation, SENNM greatly boosts the computational efficiency and accuracy. As for application, the SENNM is successfully applied to derive several new analytical solutions of the modified Camassa–Holm equation, the <span>((2+1))</span>-dimensional potential Kadomtsev–Petviashvili equation, and the <span>((2+1))</span>-dimensional Yu–Toda–Sasa–Fukuyama equation. Furthermore, the systematic formulation of trial functions is achieved by incorporating appropriately designed activation functions into the NN architecture. By embedding the sub-equation method in the NN framework, solutions previously unreported are derived, which are expressed in hyperbolic, trigonometric, and rational forms. Three-dimensional density surfaces, two-dimensional line plots, and polar plots are shown to describe the dynamic behavior of the solutions. This research offers a new computational framework for the problem of NLPDEs, whose applications have widespread use in scientific and engineering problems.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 9","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148838367","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":"Entropy-Prescription Dependence of the Thermodynamic Topology of Charged Rotating Black Holes with Scalar Hair","authors":"Abdelhay Salah Mohamed,&nbsp;Aqsa Mehmood,&nbsp;M. Umair Shahzad,&nbsp;Muhammad Zeshan Ashraf","doi":"10.1007/s10773-026-06454-7","DOIUrl":"10.1007/s10773-026-06454-7","url":null,"abstract":"<div><p>A thorough investigation of the thermodynamics of charged rotating black holes with scalar hair (CR-SH BHs) constructed by the Newman-Janis algorithm (NJA) is conducted in this study with a special focus on comparing three entropy formulations, such as Bekenstein-Hawking, Barrow, and logarithmic-corrected entropy. The analysis is performed in a canonical ensemble at fixed charge, angular momentum, and hair parameter, which leads to a closed form <i>M</i>(<i>S</i>, <i>J</i>, <i>q</i>, <i>s</i>) and verifies that the first law of thermodynamics and corresponding Smarr relation close identically. The conjugate temperature is fixed for the first law itself, <span>(T_X = (partial M/partial S_X)_{J,q,s})</span> for each entropy prescription, so that free energy, heat capacity and topological analysis are mutually consistent with each framework. The logarithmic corrections introduced in entropy formulations correspond to the quantum thermal fluctuations and become more pronounced in smaller BHs. Both Bekenstein-Hawking and Barrow entropies yield a topological charge 0, while the logarithmic entropy gives <span>(-1)</span>, indicating that the topological classification is sensitive to the entropy prescription. The heat capacity shows a single Davies divergence in both Bekenstein-Hawking and Barrow entropies, whereas logarithmic corrected entropy yields no divergence or pair of divergences bounding a narrow window of positive heat capacity. This change of class across prescriptions reflects the sensitivity of the topological classification to the adopted entropy functional and should not be interpreted as a phase transition of a single BH system.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 9","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148838221","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":"Detection of Genuine Multipartite Entanglement Based on Siamese Networks","authors":"Zhong-Teng Kan,&nbsp;Shu-Qian Shen,&nbsp;Ming Li,&nbsp;Lei Li","doi":"10.1007/s10773-026-06460-9","DOIUrl":"10.1007/s10773-026-06460-9","url":null,"abstract":"<div><p>Quantum entanglement is a highly valuable resource for quantum information processing, among which genuine multipartite entanglement (GME) plays a pivotal role in quantum information science. In this paper, we propose a Siamese convolutional neural network–Transformer model, together with an enhanced version incorporating a squeeze-and-excitation mechanism, for detecting GME in three- and four-qubit systems. Experimental results show that the proposed Siamese network models achieve classification accuracies above 99% for both three- and four-qubit systems.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 9","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148837468","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":"Energy Spectrum of Massless Klein–Gordon Field in Differentially Curved Spacetime Geometry","authors":"Muhammad Khairul Annam Najahy,&nbsp;Briant Sabathino Harya Wibawa,&nbsp;C. Cari,&nbsp;A. Suparmi","doi":"10.1007/s10773-026-06447-6","DOIUrl":"10.1007/s10773-026-06447-6","url":null,"abstract":"<div><p>This study investigates the Klein–Gordon equation with massless in the Eddington-inspired Born–Infeld (EiBI) gravitational framework, incorporating the effects of the Wu–Yang magnetic monopole, the Aharonov–Bohm flux, and the pseudoharmonic potential. The formulation is developed in a global monopole space–time, allowing the combined geometric, topological, and nonlinear gravitational contributions to modify the relativistic energy spectrum. Because the corresponding radial equation admits Confluent Heun series/polynomials solution, part of the energy levels that satisfy conditional exact solvability are reported. The graphical analysis shows how the parameters <span>(alpha)</span>, <span>(sigma)</span>, <span>(kappa)</span>, <span>(A)</span>, and <span>(B)</span> influence the spectral structure and reveal features not present in earlier models, particularly in relation to the stability of energy levels under variations of external fields and curvature deformation. Additional emphasis is placed on two parameters: the oscillator frequency <span>(Omega)</span>, controlling the confinement strength, and the Aharonov–Bohm flux <span>(phi)</span>, reflecting the sensitivity of the spectra to gauge-generated geometric phases. These results highlight the stabilizing role of EiBI gravity and show how nonlinear geometry and topological fields collectively shape the quantum behavior of massless scalar relativistic particles in curved space–time.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 9","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148837868","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":"Characterization of Generalized Quasi-Einstein Manifolds and Modified Gravity","authors":"Uday Chand De,&nbsp;Hülya Bağdatlı Yılmaz","doi":"10.1007/s10773-026-06457-4","DOIUrl":"10.1007/s10773-026-06457-4","url":null,"abstract":"<div><p>In this work, a detailed examination of a specific case of a generalized quasi-Einstein manifold <span>( (GQE)_{n} )</span> is provided. We begin by exploring generalized quasi-Einstein spacetimes under certain conditions, with a primary focus on cases that admit a parallel time-like vector field. Among the findings, it is demonstrated that such spacetimes can be categorized as generalized Robertson-Walker, Robertson-Walker, and quasi-constant curvature spacetimes. Additionally, the physical implications of these results are discussed. Furthermore, <span>( (GQE)_{4} )</span> spacetimes that admit <span>(mathcal {F}(mathfrak {R}))</span>-gravity and feature a parallel unit time-like vector field are investigated. In this context, a flat Friedmann-Robertson-Walker (FRW) model is established to extract exact cosmological solutions for the Hubble parameter and the scale factor. Various energy conditions are analyzed based on geometric constraints arising from <span>(mathcal {F}(mathfrak {R}))</span>-gravity. Finally, a non-trivial 4-dimensional GQE spacetime is constructed and its exact, closed-form potential function is obtained to verify the analytical feasibility of our model.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 9","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148837423","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":"On the Propagation and Head-on Collision for Ion-Acoustic KdV-and mKdV-Solitons in Non-Maxwellian Bi-ion Plasmas","authors":"Badriah M. Alotaibi,&nbsp;Shahida Parveen,&nbsp;Ajwa Abdullah,&nbsp;Samir A. El-Tantawy","doi":"10.1007/s10773-026-06446-7","DOIUrl":"10.1007/s10773-026-06446-7","url":null,"abstract":"<div><p>The Martian plasma environment provides a natural laboratory for exploring nonlinear wave dynamics in multi-component, weakly collisional media with superthermal particle populations. Motivated by in situ observations of superthermal electrons and multi-ion species in Mars’ ionosphere, this work develops a fluid plasma model comprising oppositely charged ions and two distinct <span>(kappa )</span>-distributed electron populations, representing photoelectrons and solar-wind-origin electrons. Within this framework, the extended Poincaré-Lighthill-Kuo (EPLK) perturbation technique is used to derive evolutionary wave equations that govern head-on soliton collisions, including two coupled Korteweg-de Vries (KdV) equations and two coupled modified Korteweg-de Vries (mKdV) equations for small-amplitude electrostatic modes, together with explicit expressions for soliton parameters and collision-induced phase shifts. The analysis reveals how key physical ingredients such as the spectral indices of the kappa distributions, the relative densities and temperatures of the ion and electron species, and the charge state of heavy ions control the polarity, width, and speed of ion acoustic and related solitary structures, as well as the magnitude and sign of their corresponding phase shift. Numerical evaluation of the phase corrections shows that superthermal electrons and a realistic Martian composition can strongly enhance or suppress the interaction-induced delays relative to Maxwellian benchmarks, leading to regimes in which collisions are nearly elastic, and others in which pronounced trajectory deflections occur. These results highlight the crucial role of nonthermal electron populations in shaping solitary wave propagation and interactions in Mars’ ionosphere, provide a baseline for interpreting soliton signatures in <span>(kappa -)</span>dominated planetary plasmas, and indicate where more complete models, including inhomogeneity and magnetic fields, will be required.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 9","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148837425","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}