International Journal of Theoretical Physics最新文献

{"title":"New Similarity Reductions, Exact Solutions and New Physical Phenomena for a Nonlinear Dispersive Long Wave Equation","authors":"Hanqin Xiao,&nbsp;Shaowei Liu","doi":"10.1007/s10773-026-06442-x","DOIUrl":"10.1007/s10773-026-06442-x","url":null,"abstract":"<div><p>In this manuscript, based on the Clarkson-Kruskal (CK) direct method, we study the well-known (2+1)-dimensional Kadomtsev-Petviashvili-Benjamin-Bona-Mahony (KPBBM) equation, which describes the propagation of small-amplitude long waves in a nonlinear dispersive medium. By employing a “decoupling approach”, we modified the common CK method. Together with proving the equivalence between two reduction forms, we greatly reduced computational complexity and successfully overcame the lengthy, intricate calculations inherent in the common CK method. Hence, we obtain new exact solutions and new similarity reductions of the KPBBM equation. Compared with the existing relevant work, the feature of this manuscript lies in that, firstly, we obtain a variety of new exact solutions for the KPBBM equation, including soliton–lump collision solutions, lump–lump collision solutions, mixed Airy-lump wave solutions, Airy function solutions, and Weber–Hermite function solutions, etc. To the best of our knowledge, these solutions have not been reported by other researchers. These new analytical solutions and reduced equations are great significance for the physical understanding of the KPBBM equation and the natural phenomena it describes; Secondly, in particular, for the KPBBM equation, two new types of solutions, i.e., the Airy function solutions and the Weber–Hermite function solutions, are reported here for the first time. They have important applications in ocean water dynamics and wave propagation with Gaussian decay in the distance region, respectively; Thirdly, we find the “independence condition” for the KPBBM equation. The independence condition enables us to observe, for the first time, that complex solutions can be approximately decomposed into two independently interacting waves. In nonlinear systems, the phenomenon of approximately independent collision of multiple waves resembling linear superposition effects is commonly seen among soliton solutions, such as in two-soliton solutions. Here, unlike common multi-soliton collisions, the nonlinear KPBBM system exhibits approximately independent collision phenomena among waves of different types, such as between a soliton and a lump. This condition thus provides a more comprehensive understanding of the nonlinear dynamics of complex solutions. In summary, our results provide a more thorough understanding of the integrable structure of the KPBBM nonlinear system and the dynamics of its collision wave propagation phenomena, which enhance understanding of shallow-water wave evolution and nonlinear wave interactions.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 8","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148782218","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":"Blocking Temperature and Magnetic Properties of 2D Antiferromagnetic MnPS(_3) Monolayer","authors":"D. Bokpe,&nbsp;E. M. Jalal,&nbsp;H. Kerrai,&nbsp;K. El Kihel,&nbsp;T. D. Oke","doi":"10.1007/s10773-026-06439-6","DOIUrl":"10.1007/s10773-026-06439-6","url":null,"abstract":"<div><p>In this work, the magnetic properties and blocking temperature of an antiferromagnetic MnPS<span>(_3)</span> monolayer are investigated using the mean field approximation combined with the Ising model. The influence of key system parameters, such as the exchange interactions (J<span>(_1)</span> and J<span>(_2)</span>) and the external magnetic field h, on the magnetization, susceptibility, specific heat and internal energy are systematically analyzed and discussed. Notably, the study reveals that the blocking temperature decreases with increasing external magnetic field, while its behavior is also influenced by the exchange interactions.. In the second part, a specific set of exchange parameters yields a Néel temperature T<span>(_N)</span>=113.45 K which is consistent with values reported in previous studies for MnPS<span>(_3)</span>.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 8","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148751531","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":"Generalized Marginals of Tie -Wigner Distribution Nand Lagrangian Tomography","authors":"Maurice A. de Gosson","doi":"10.1007/s10773-026-06440-z","DOIUrl":"10.1007/s10773-026-06440-z","url":null,"abstract":"<div><p>We develop a symplectic formulation of the Lagrangian Radon transform based on the transitive action of the symplectic group on the Lagrangian Grassmannian. This geometric framework naturally extends the classical notion of the marginals of the Wigner transform, viewed as elementary tomograms, to arbitrary Lagrangian subspaces. The resulting generalized tomography provides a unified treatment of position and momentum measurements related by symplectic rotations. As applications, we revisit the Pauli reconstruction problem and establish reconstruction formulas for density operators from generalized Lagrangian tomograms.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 8","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148751774","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":"Probabilistic Controlled Quantum Teleportation of an Arbitrary Qubit via a Four-Qubit Asymmetric Entangled State and Its Qiskit-Based Monte Carlo Simulation","authors":"Shifan Yu","doi":"10.1007/s10773-026-06433-y","DOIUrl":"10.1007/s10773-026-06433-y","url":null,"abstract":"<div><p>We propose a probabilistic controlled quantum teleportation (CQT) protocol for an arbitrary single-qubit state using a non-symmetric B1.1-class four-qubit entangled channel. An auxiliary qubit and a non-unitary positive operator-valued measure (POVM) filter compensate the channel-induced coefficient distortion on accepted branches. The physical success probability is analytically <span>(P_{textrm{succ}}=1/3)</span>, whereas <span>(12.5%)</span> is a per-attempt resource index and not a success probability. For a Haar-uniform input ensemble conditioned on Alice’s <span>(|Phi ^+rangle )</span> outcome, the receiver’s optimal average fidelity without Charlie’s record is 8/9; thus, the controller’s record is necessary for deterministic, input-independent recovery of a generic unknown qubit, but no claim of absolute controller authority is made. We simulate the protocol with Qiskit Aer using six representative input states, including complex relative phases. For each noise setting, we report conditional fidelity, acceptance probability, and their product from 10,000 shots. The simulations provide a reproducible characterization of the trade-off between postselected fidelity and accepted-output rate under amplitude- and phase-damping noise.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 8","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148751929","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":"Topolons: Stable Particle-Like Remnants of Collapsed Vacuum Bubbles in a Three-Form Gauge Sector","authors":"Muhammad Ghulam Khuwajah Khan","doi":"10.1007/s10773-026-06420-3","DOIUrl":"10.1007/s10773-026-06420-3","url":null,"abstract":"<div><p>We study a three-form gauge sector in four spacetime dimensions coupled to electrically charged spherical membranes whose worldvolume dynamics are governed by a Dirac–Born–Infeld action. The associated four-form field strength has no local propagating degrees of freedom and contributes a branch-dependent vacuum energy. Motivated by the Hartle–Hawking–Wu selection argument, we restrict attention to the semiclassically admissible four-form flux window for which the Hartle-Hawking wave function has support. We then endow the bubble wall with a worldvolume <i>U</i>(1) gauge field carrying quantized monopole flux <span>(n in mathbb {Z})</span> and evaluate the full DBI energy of the resulting spherical configurations. We show that the energetically preferred branch collapses toward a microscopic core rather than stabilizing at finite radius, but for nonzero monopole flux the energy does not vanish in the collapsed limit. Instead, the bubble relaxes to a finite-energy remnant whose mass is set by the wall scale and the conserved flux. We interpret these objects as stable flux-supported particle-like states, which we call topolons. Within the admissible sector, the effective energy analysis distinguishes stable collapsed remnants from the contrasting runaway vacuum-decay channel, thereby isolating the sector relevant for cosmological relic formation. At macroscopic distances, topolons behave as heavy localized states and provide a concrete microphysical realization of a dark relic candidate. The detailed cosmological abundance and phenomenology are left for future work. More broadly, the present construction supplies the nonperturbative remnant component of an economical three-form framework in which the homogeneous four-form flux may neutralize the dominant permanent vacuum-energy contribution, while a dynamical scalar supplies the temporary positive energy required for a no-boundary inflationary history. Additional four-form dynamics, another sector, or presently unknown physics may leave the small residual vacuum energy observed at late times. The present paper does not claim a complete unified cosmology, but establishes the microscopic topolon sector required for such a program.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 8","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148751677","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":"Exact Thermodynamics and Auxiliary-Field Analysis of a Minimal Interacting Fermionic Dimer","authors":"Batool A Abu Saleh,&nbsp;Amani Kraishan","doi":"10.1007/s10773-026-06432-z","DOIUrl":"10.1007/s10773-026-06432-z","url":null,"abstract":"<div><p>Single-mode quartic fermionic Hamiltonians are often used as pedagogical examples, but their interaction terms are algebraically reducible through the identity <span>(n^2=n)</span> and therefore do not represent genuine many-body interactions. In this work, we identify a minimal genuinely interacting extension in the form of a two-mode fermionic dimer with intermode density coupling. Working in the grand-canonical ensemble, we derive the exact finite-temperature partition function, many-body spectrum, average filling, double occupancy, entropy, thermal response functions, and single-particle Green’s functions. The exact solution shows explicitly how the chemical potential controls the filling, while the interaction selectively modifies the doubly occupied sector and generates interaction-dependent spectral branches beyond a simple one-body level shift. We also construct the coherent-state Grassmann path-integral representation and formulate a <i>two-channel</i> Hubbard–Stratonovich decomposition based on charge and imbalance fields. This representation makes explicit the sign-dependent role of real and imaginary auxiliary-field couplings, with an imaginary coupling appearing in the charge channel for repulsive interaction. It also provides a channel-complete starting point for comparison with the exact grand-canonical solution. Although the Hubbard dimer has been studied extensively, the channel dependence of static auxiliary-field approximations and its quantitative finite-temperature consequences have not, to our knowledge, been presented in this compact grand-canonical form. A numerical comparison shows that the static two-field approximation captures the qualitative filling-controlled behavior and avoids the unphysical negative double occupancy produced by the scalar one-field approximation, although quantitative deviations remain because of the static restriction. The scalar density-channel static approximation considered here is therefore interpreted only as a diagnostic example, since it effectively assigns the wrong sign to the interaction contribution in the doubly occupied sector. The analysis establishes a sharp distinction between algebraically reducible quartic fermion terms and genuine density-density interactions, and provides a compact exact benchmark for analytical, numerical, and pedagogical studies of interacting fermionic systems.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 8","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148751470","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":"Characterizing the Thermal Quantum Correlations in a Two-Qubit Heisenberg XYZ Spin-1/2 Chain Under an External Magnetic Field with Spin-Orbit and Zeeman Interactions","authors":"Mounaim Hamdoune,&nbsp;Mohammed Daoud","doi":"10.1007/s10773-026-06441-y","DOIUrl":"10.1007/s10773-026-06441-y","url":null,"abstract":"<div><p>We present a comprehensive theoretical study of thermal quantum correlations in a two-qubit Heisenberg XYZ spin-1/2 chain under the combined influence of an external magnetic field, Dzyaloshinskii-Moriya (DM) antisymmetric and Kaplan-Shekhtman-Entin-Wohlman-Aharony (KSEA) symmetric spin-orbit interactions, and Zeeman splitting. We derive closed-form analytical expressions for two complementary discord-type quantifiers – the trace distance discord (TDD) and the local quantum uncertainty (LQU) – as functions of temperature, magnetic field, spin-orbit coupling parameters, and Zeeman energy. Our analysis reveals that the DM interaction provides robust thermal protection for quantum correlations, while the KSEA interaction produces asymmetric effects on the two correlation measures. The magnetic field and Zeeman interaction offer effective control knobs for modulating correlations, exhibiting non-monotonic behavior that arises from the competition between Zeeman polarization and exchange interactions. We extend our analysis to both ferromagnetic and antiferromagnetic exchange regimes, demonstrating that the qualitative behavior of quantum correlations is preserved across both phases. Finally, we connect our theoretical findings to realistic solid-state platforms, including semiconductor quantum dots and molecular magnets, providing experimental benchmarks for current quantum information technologies.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 8","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148751456","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":"Quantum Inequalities From the Second Law","authors":"Andrea Palessandro","doi":"10.1007/s10773-026-06434-x","DOIUrl":"10.1007/s10773-026-06434-x","url":null,"abstract":"<div><p>Quantum field theory allows local violations of the classical energy conditions, such as regions of negative energy density. The Ford–Roman quantum inequalities quantify how negative these regions can be and for how long. We present a derivation of these inequalities from the second law of thermodynamics, in an operational framework that couples the field to a small thermal detector. The detector acts as a physical probe of the field’s energy density and, by the non-negativity of the entanglement entropy between the two systems, one can show that its heat loss is bounded from below by a state-independent quantity.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 8","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148751471","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":"Algebraic Approaches to Bose-Einstein Condensation","authors":"Lorenzo Pettinari","doi":"10.1007/s10773-026-06438-7","DOIUrl":"10.1007/s10773-026-06438-7","url":null,"abstract":"<div><p>We review two recent applications of operator-algebraic methods to the analysis of homogeneous Bose gases at finite temperature. The first part concerns the semiclassical description of Bose–Einstein condensation in the framework of Weyl <span>(C^*)</span>-algebras. In this setting, the semiclassical parameter is naturally linked to the density of the system, and the classical weak KMS condition emerges as the limit of quantum equilibrium states. We show in particular that the condensate structure is preserved in a suitable large-density regime. The second part discusses a joint work with Prof. Jan Dereziński which the Araki–Woods representation is used to formulate a systematic perturbative theory for interacting Bose gases at positive temperature. Within this representation, thermal effects are encoded directly in the field operators, allowing for a transparent implementation of Wick’s theorem and the computation of damping coefficients via the Fermi Golden Rule. The review synthesizes results obtained in two recent works presented at IQSA2025, emphasizing the conceptual role of algebraic methods in connecting semiclassical analysis, equilibrium states, and finite-temperature perturbation theory.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 8","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s10773-026-06438-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148751036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced Two-Dimensional Atomic Localization Using Super-Gaussian Laser Beams and Spontaneously Generated Coherence","authors":"Sabz Ali,&nbsp;Shabir Ahmad,&nbsp;Mansoor Khan,&nbsp;Haseena Bibi,&nbsp;Wasif ur Rehman,&nbsp;Habibur Rahman,&nbsp;Muhammad Adil Khan,&nbsp;Youyi Sun,&nbsp;Zoaloon Ahmad Abeid Allah Saad","doi":"10.1007/s10773-026-06436-9","DOIUrl":"10.1007/s10773-026-06436-9","url":null,"abstract":"<div><p>Atomic localization with sub-wavelength precision has attracted considerable attention due to its applications in atom lithography, laser cooling, and quantum technologies. In this work, we theoretically investigate the role of spontaneously generated coherence (SGC) in controlling atomic localization using super-Gaussian laser beams. Localization can be effectively manipulated in both one- and two-dimensional configurations by varying the beam exponent. The presence of SGC significantly improves the probability of localization while reducing spatial uncertainty, with the localization increasing from approximately 20<span>(%)</span> to nearly 100<span>(%)</span> as the SGC parameter increases. The superposition of orthogonal standing-wave fields enables precise two-dimensional localization, while the coherent driving field reduces peak width without affecting amplitude. These results demonstrate that the combined effects of super-Gaussian beam shaping and SGC provide a tunable mechanism for achieving enhanced localization beyond conventional Gaussian-field limits. The proposed scheme offers promising applications in atom nano-lithography, laser cooling and trapping, and Bose-Einstein condensation.</p></div>","PeriodicalId":597,"journal":{"name":"International Journal of Theoretical Physics","volume":"65 8","pages":""},"PeriodicalIF":2.3,"publicationDate":"2026-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148751430","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}