Pub Date : 2026-01-07DOI: 10.1016/j.aop.2026.170346
Hassan Hassanabadi , Kangxian Guo , Liangliang Lu , Edilberto O. Silva
We investigate the optical and quantum mechanical properties of a charged spinless particle confined in a two-dimensional quantum ring under the simultaneous influence of a spiral dislocation and an external magnetic field. The dislocation is modeled by a torsion-induced metric that alters the spatial geometry without introducing curvature. Using the minimal coupling procedure in curved space, we derive a modified Schrödinger equation incorporating both topological and electromagnetic effects. The geometric deformation leads to an energy-dependent effective potential, enabling a tunable control over the bound-state spectrum. We analyze how the spiral dislocation modifies the absorption coefficient, refractive index variation, and photoionization cross-section. The results demonstrate that the dislocation not only shifts the resonance peaks but also enhances or suppresses specific optical transitions depending on the angular momentum. These findings open up possibilities for geometrically tuning light–matter interactions in topological quantum devices.
{"title":"Spiral dislocation as a tunable geometric parameter for optical responses in quantum rings","authors":"Hassan Hassanabadi , Kangxian Guo , Liangliang Lu , Edilberto O. Silva","doi":"10.1016/j.aop.2026.170346","DOIUrl":"10.1016/j.aop.2026.170346","url":null,"abstract":"<div><div>We investigate the optical and quantum mechanical properties of a charged spinless particle confined in a two-dimensional quantum ring under the simultaneous influence of a spiral dislocation and an external magnetic field. The dislocation is modeled by a torsion-induced metric that alters the spatial geometry without introducing curvature. Using the minimal coupling procedure in curved space, we derive a modified Schrödinger equation incorporating both topological and electromagnetic effects. The geometric deformation leads to an energy-dependent effective potential, enabling a tunable control over the bound-state spectrum. We analyze how the spiral dislocation modifies the absorption coefficient, refractive index variation, and photoionization cross-section. The results demonstrate that the dislocation not only shifts the resonance peaks but also enhances or suppresses specific optical transitions depending on the angular momentum. These findings open up possibilities for geometrically tuning light–matter interactions in topological quantum devices.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"486 ","pages":"Article 170346"},"PeriodicalIF":3.0,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2026-01-07DOI: 10.1016/j.aop.2026.170345
Alexey E. Rastegin
Kirkwood–Dirac quasiprobabilities are currently the subject of active studies. Such quasiprobabilities often give more convenient descriptions of measurement statistics. It is an alternative to the Wigner function. Methods of quantum information science use generalized measurements. Overcomplete sets of states are inevitable for these purposes. Here, complex projective two-designs are of certain interest. They include symmetric informationally complete measurements and complete sets of mutually unbiased bases. This study examines Kirkwood–Dirac quasiprobabilities for induced quantum measurements. It estimates norms and anti-norms of the matrices consisting of quasiprobabilities. Entropic uncertainty relations appear for unravelings of the corresponding quantum channels. Qubit examples of projective designs show the usefulness of the presented inequalities.
{"title":"Kirkwood–Dirac quasiprobabilities for measurements assigned to a projective two-design","authors":"Alexey E. Rastegin","doi":"10.1016/j.aop.2026.170345","DOIUrl":"10.1016/j.aop.2026.170345","url":null,"abstract":"<div><div>Kirkwood–Dirac quasiprobabilities are currently the subject of active studies. Such quasiprobabilities often give more convenient descriptions of measurement statistics. It is an alternative to the Wigner function. Methods of quantum information science use generalized measurements. Overcomplete sets of states are inevitable for these purposes. Here, complex projective two-designs are of certain interest. They include symmetric informationally complete measurements and complete sets of mutually unbiased bases. This study examines Kirkwood–Dirac quasiprobabilities for induced quantum measurements. It estimates norms and anti-norms of the matrices consisting of quasiprobabilities. Entropic uncertainty relations appear for unravelings of the corresponding quantum channels. Qubit examples of projective designs show the usefulness of the presented inequalities.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"486 ","pages":"Article 170345"},"PeriodicalIF":3.0,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2026-01-03DOI: 10.1016/j.aop.2025.170334
M. Ilyas , Khalid Masood , N.A. Shah
We investigate static, spherically symmetric wormhole solutions in modified Gauss–Bonnet () gravity incorporating non-commutative geometry. To construct these solutions, we employ two distinct methods: first, by assuming a specific model and deriving the corresponding shape function ; and second, by specifying and deriving the required model. Remarkably, the first approach yields a solution threaded by normal matter that satisfies the energy conditions across the entire radial range. The second approach also yields a physically valid solution, but only for large values of . Our analysis of the energy conditions provides valuable insights into the interplay between geometry, gravity, and matter in this framework.
{"title":"Non-commutative wormhole solutions in Higher Order Gauss Bonnet Gravity","authors":"M. Ilyas , Khalid Masood , N.A. Shah","doi":"10.1016/j.aop.2025.170334","DOIUrl":"10.1016/j.aop.2025.170334","url":null,"abstract":"<div><div>We investigate static, spherically symmetric wormhole solutions in modified Gauss–Bonnet (<span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></math></span>) gravity incorporating non-commutative geometry. To construct these solutions, we employ two distinct methods: first, by assuming a specific <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></math></span> model and deriving the corresponding shape function <span><math><mrow><mi>b</mi><mrow><mo>(</mo><mi>r</mi><mo>)</mo></mrow></mrow></math></span>; and second, by specifying <span><math><mrow><mi>b</mi><mrow><mo>(</mo><mi>r</mi><mo>)</mo></mrow></mrow></math></span> and deriving the required <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>G</mi><mo>)</mo></mrow></mrow></math></span> model. Remarkably, the first approach yields a solution threaded by normal matter that satisfies the energy conditions across the entire radial range. The second approach also yields a physically valid solution, but only for large values of <span><math><mi>r</mi></math></span>. Our analysis of the energy conditions provides valuable insights into the interplay between geometry, gravity, and matter in this framework.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"486 ","pages":"Article 170334"},"PeriodicalIF":3.0,"publicationDate":"2026-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145973993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2026-01-03DOI: 10.1016/j.aop.2026.170342
Valery Shchesnovich
Solvable bosonic models provide a fundamental framework for describing light propagation in nonlinear media, including optical down-conversion processes that generate squeezed states of light and their higher-order generalizations. In quantum optics a central objective is to determine the time evolution of a given initial state. Exact analytic solution to the state-evolution problem is presented, applicable to a broad class of solvable bosonic models and arbitrary initial states. Moreover, the characteristic equation governing the energy spectrum is derived and the eigenstates are found in the form of continued fractions and as the principal minors of the associated Jacobi matrix. The results provide a solid analytical framework for discussion of exactly solvable bosonic models.
{"title":"Exact state evolution and energy spectrum in solvable bosonic models","authors":"Valery Shchesnovich","doi":"10.1016/j.aop.2026.170342","DOIUrl":"10.1016/j.aop.2026.170342","url":null,"abstract":"<div><div>Solvable bosonic models provide a fundamental framework for describing light propagation in nonlinear media, including optical down-conversion processes that generate squeezed states of light and their higher-order generalizations. In quantum optics a central objective is to determine the time evolution of a given initial state. Exact analytic solution to the state-evolution problem is presented, applicable to a broad class of solvable bosonic models and arbitrary initial states. Moreover, the characteristic equation governing the energy spectrum is derived and the eigenstates are found in the form of continued fractions and as the principal minors of the associated Jacobi matrix. The results provide a solid analytical framework for discussion of exactly solvable bosonic models.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"486 ","pages":"Article 170342"},"PeriodicalIF":3.0,"publicationDate":"2026-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2025-12-31DOI: 10.1016/j.aop.2025.170329
Ipsita Mandal
Spin- and valley-polarized fractionally-filled moiré flatbands are known to host emergent Fermi-liquid phases, when analysed with the help of a dual description in terms of holes. The dominant Coulomb interactions in an almost flatband endow the fermions with a nontrivial dispersion, when the system is described in terms of the hole operators (rather than the particle operators). In particular, for one-fourth filling, the Fermi surface takes a quasi-triangular shape, which brings about the possibility of charge-density-wave (CDW) ordering in the ground state, characterised by the nesting vectors (). The ’s connect antipodal points of the Fermi surface (designated as hot-spots) and are found to belong to the space of reciprocal vectors of the underlying honeycomb structure. The resulting CDW order can be described in terms of instabilities caused by bosonic fields with momenta centred at , coupling with the fermions residing in the vicinity of a pair of antipodal hot-spots. When there is a transition from a Fermi liquid to a CDW state, the bosons become massless (or critical), effectuating a non-Fermi liquid behaviour. We set out to identify such non-Fermi liquid phases after constructing a minimal effective action.
{"title":"Non-Fermi liquid behaviour of CDW instabilities in fractionally-filled moiré flatbands","authors":"Ipsita Mandal","doi":"10.1016/j.aop.2025.170329","DOIUrl":"10.1016/j.aop.2025.170329","url":null,"abstract":"<div><div>Spin- and valley-polarized fractionally-filled moiré flatbands are known to host emergent Fermi-liquid phases, when analysed with the help of a dual description in terms of holes. The dominant Coulomb interactions in an almost flatband endow the fermions with a nontrivial dispersion, when the system is described in terms of the hole operators (rather than the particle operators). In particular, for one-fourth filling, the Fermi surface takes a quasi-triangular shape, which brings about the possibility of charge-density-wave (CDW) ordering in the ground state, characterised by the nesting vectors (<span><math><msub><mrow><mi>Q</mi></mrow><mrow><mi>n</mi></mrow></msub></math></span>). The <span><math><msub><mrow><mi>Q</mi></mrow><mrow><mi>n</mi></mrow></msub></math></span>’s connect antipodal points of the Fermi surface (designated as hot-spots) and are found to belong to the space of reciprocal vectors of the underlying honeycomb structure. The resulting CDW order can be described in terms of instabilities caused by bosonic fields with momenta centred at <span><math><mrow><mo>{</mo><msub><mrow><mi>Q</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>}</mo></mrow></math></span>, coupling with the fermions residing in the vicinity of a pair of antipodal hot-spots. When there is a transition from a Fermi liquid to a CDW state, the bosons become massless (or critical), effectuating a non-Fermi liquid behaviour. We set out to identify such non-Fermi liquid phases after constructing a minimal effective action.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"486 ","pages":"Article 170329"},"PeriodicalIF":3.0,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145883169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
In this study, we explore the cosmological implications of a modified gravity theory characterized by the function , where is the Ricci scalar, represents a geometric deformation term, and denotes the trace of the energy–momentum tensor. The model is reconstructed under the framework of three fundamental energy conditions: Null Energy Condition (NEC), Dominant Energy Condition (DEC), and Strong Energy Condition (SEC). We derive the corresponding Hubble parameter for each case and constrain the free parameters , , and using the latest Cosmic Chronometer (CC) and Pantheon+ Type Ia Supernova datasets. A thorough analysis of physical quantities such as pressure, energy density, and the equation of state parameter is carried out. Furthermore, diagnostic tools including the deceleration parameter , statefinder parameters , and the diagnostic are employed to assess the models viability. Our findings suggest that the model can consistently describe late-time cosmic acceleration and offers distinct behavior under different energy conditions, all while aligning with current observational data.
在这项研究中，我们探索了一个修正的引力理论的宇宙学含义，该理论的特征是函数f(R，Σ，T)，其中R是里奇标量，Σ表示几何变形项，T表示能量动量张量的轨迹。在零能条件（NEC）、优势能条件（DEC）和强能条件（SEC）三种基本能量条件的框架下重构了该模型。利用最新的Cosmic Chronometer （CC）和Pantheon+ Type Ia超新星数据集，我们推导出了每种情况下对应的哈勃参数H(z)，并约束了自由参数H0， α和β。对压力、能量密度和状态方程参数等物理量进行了深入的分析。此外，诊断工具包括减速参数q(z)、状态查找器参数{r，s}和Om(z)诊断来评估模型的可行性。我们的发现表明，该模型可以一致地描述晚期宇宙加速，并在不同能量条件下提供不同的行为，同时与当前的观测数据保持一致。
{"title":"Dark energy behavior from static equation of state in non-minimally coupled gravity with scalar deformation","authors":"N. Myrzakulov , S.H. Shekh , S.R. Bhoyar , Anirudh Pradhan","doi":"10.1016/j.aop.2025.170333","DOIUrl":"10.1016/j.aop.2025.170333","url":null,"abstract":"<div><div>In this study, we explore the cosmological implications of a modified gravity theory characterized by the function <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>,</mo><mi>Σ</mi><mo>,</mo><mi>T</mi><mo>)</mo></mrow></mrow></math></span>, where <span><math><mi>R</mi></math></span> is the Ricci scalar, <span><math><mi>Σ</mi></math></span> represents a geometric deformation term, and <span><math><mi>T</mi></math></span> denotes the trace of the energy–momentum tensor. The model is reconstructed under the framework of three fundamental energy conditions: Null Energy Condition (NEC), Dominant Energy Condition (DEC), and Strong Energy Condition (SEC). We derive the corresponding Hubble parameter <span><math><mrow><mi>H</mi><mrow><mo>(</mo><mi>z</mi><mo>)</mo></mrow></mrow></math></span> for each case and constrain the free parameters <span><math><msub><mrow><mi>H</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span>, <span><math><mi>α</mi></math></span>, and <span><math><mi>β</mi></math></span> using the latest Cosmic Chronometer (CC) and Pantheon+ Type Ia Supernova datasets. A thorough analysis of physical quantities such as pressure, energy density, and the equation of state parameter is carried out. Furthermore, diagnostic tools including the deceleration parameter <span><math><mrow><mi>q</mi><mrow><mo>(</mo><mi>z</mi><mo>)</mo></mrow></mrow></math></span>, statefinder parameters <span><math><mrow><mo>{</mo><mi>r</mi><mo>,</mo><mi>s</mi><mo>}</mo></mrow></math></span>, and the <span><math><mrow><msub><mrow><mi>O</mi></mrow><mrow><mi>m</mi></mrow></msub><mrow><mo>(</mo><mi>z</mi><mo>)</mo></mrow></mrow></math></span> diagnostic are employed to assess the models viability. Our findings suggest that the model can consistently describe late-time cosmic acceleration and offers distinct behavior under different energy conditions, all while aligning with current observational data.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"486 ","pages":"Article 170333"},"PeriodicalIF":3.0,"publicationDate":"2025-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2025-12-30DOI: 10.1016/j.aop.2025.170327
Harshit Sharma, Udaysinh T. Bhosale
We study an -spin Floquet model with infinite-range Ising interactions and derive the general formula to calculate the single-qubit reduced density matrix and its linear entropy and entanglement entropy for any and . For systems up to 10 qubits, we analytically obtain the eigensystem, entanglement measures, and time-averaged linear entropy for arbitrary initial states and special values of and . For a special class of initial states and specific values of , the model was studied in earlier work. Here, we generalize those results to arbitrary initial states. We numerically find that the average concurrence decreases with , implying multipartite nature of entanglement. We numerically show that for both single-qubit and half-bipartitaion cases , when indicating non-integrability. Whereas for and , it deviates from 1, indicating integrability. In integrable cases, depth in entanglement grows with partition size. Possible experimental realizations are discussed.
{"title":"Exact solvability of entanglement for arbitrary initial state in an infinite-range Floquet system","authors":"Harshit Sharma, Udaysinh T. Bhosale","doi":"10.1016/j.aop.2025.170327","DOIUrl":"10.1016/j.aop.2025.170327","url":null,"abstract":"<div><div>We study an <span><math><mi>N</mi></math></span>-spin Floquet model with infinite-range Ising interactions and derive the general formula to calculate the single-qubit reduced density matrix and its linear entropy and entanglement entropy for any <span><math><mrow><mi>N</mi><mo>,</mo><mi>J</mi></mrow></math></span> and <span><math><mi>τ</mi></math></span>. For systems up to 10 qubits, we analytically obtain the eigensystem, entanglement measures, and time-averaged linear entropy for arbitrary initial states <span><math><mrow><mo>|</mo><msub><mrow><mi>θ</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>,</mo><msub><mrow><mi>ϕ</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>〉</mo></mrow></math></span> and special values of <span><math><mi>J</mi></math></span> and <span><math><mrow><mi>τ</mi><mo>=</mo><mi>π</mi><mo>/</mo><mn>4</mn></mrow></math></span>. For a special class of initial states and specific values of <span><math><mi>J</mi></math></span>, the model was studied in earlier work. Here, we generalize those results to arbitrary initial states. We numerically find that the average concurrence decreases with <span><math><mi>N</mi></math></span>, implying multipartite nature of entanglement. We numerically show that for both single-qubit and half-bipartitaion cases <span><math><mrow><mrow><mo>〈</mo><msub><mrow><mi>S</mi></mrow><mrow><mi>V</mi><mi>N</mi></mrow></msub><mo>〉</mo></mrow><mo>/</mo><msub><mrow><mi>S</mi></mrow><mrow><mi>M</mi><mi>a</mi><mi>x</mi></mrow></msub><mo>→</mo><mn>1</mn></mrow></math></span>, when <span><math><mrow><mi>J</mi><mo>≠</mo><mn>1</mn><mo>,</mo><mn>1</mn><mo>/</mo><mn>2</mn></mrow></math></span> indicating non-integrability. Whereas for <span><math><mrow><mi>J</mi><mo>=</mo><mn>1</mn></mrow></math></span> and <span><math><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></math></span>, it deviates from 1, indicating integrability. In integrable cases, depth in entanglement grows with partition size. Possible experimental realizations are discussed.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"486 ","pages":"Article 170327"},"PeriodicalIF":3.0,"publicationDate":"2025-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145883113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2025-12-22DOI: 10.1016/j.aop.2025.170331
Nuno Barros e Sá
We present proofs of two results: (a) The currents arising from Noether’s first theorem in a physical theory with local invariance can always be decomposed into two terms, one of them vanishing on-shell, and the other having an off-shell vanishing divergence, or that they are improper, using the original terminology of Noether; (b) When there is a current which is covariantly conserved, it differs from the canonical current by an improper current. Both proofs are performed in the most general case, that is, for arbitrary maximal order of the derivatives of the dynamical fields of the theory in the Lagrangian, and for arbitrary maximal order of the derivatives of the parameters of the symmetry transformations present in the infinitesimal transformations of the fields and spacetime coordinates. Both proofs are made using only . These are alternative proofs of known results which, besides making use of elementary calculus only, rendering them accessible to a large number of physicists, present the novelty of providing, in both cases, explicit formulae for the decomposition of the improper currents into their two terms (the one vanishing on-shell and the one whose divergence vanishes off-shell).
{"title":"Improper currents in theories with local invariance","authors":"Nuno Barros e Sá","doi":"10.1016/j.aop.2025.170331","DOIUrl":"10.1016/j.aop.2025.170331","url":null,"abstract":"<div><div>We present proofs of two results: (a) The currents arising from Noether’s first theorem in a physical theory with local invariance can always be decomposed into two terms, one of them vanishing on-shell, and the other having an off-shell vanishing divergence, or that they are improper, using the original terminology of Noether; (b) When there is a current which is covariantly conserved, it differs from the canonical current by an improper current. Both proofs are performed in the most general case, that is, for arbitrary maximal order of the derivatives of the dynamical fields of the theory in the Lagrangian, and for arbitrary maximal order of the derivatives of the parameters of the symmetry transformations present in the infinitesimal transformations of the fields and spacetime coordinates. Both proofs are made using only . These are alternative proofs of known results which, besides making use of elementary calculus only, rendering them accessible to a large number of physicists, present the novelty of providing, in both cases, explicit formulae for the decomposition of the improper currents into their two terms (the one vanishing on-shell and the one whose divergence vanishes off-shell).</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"485 ","pages":"Article 170331"},"PeriodicalIF":3.0,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145836665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2025-12-22DOI: 10.1016/j.aop.2025.170294
G.G.L. Nashed , A. Eid
We develop a model of Einstein gravity coupled to two scalar fields that admits exact analytical solutions representing a realistic compact stellar object. To this end, we derive the equations of motion describing a spherically symmetric spacetime within this framework. The resulting system consists of three equations involving eight unknown functions: three associated with the scalar field coefficients, three arising from the energy–momentum tensor components, and two corresponding to the metric potentials. It is shown that one scalar field coefficient vanishes identically, reducing the number of unknowns to seven. To close the system, four additional constraints are imposed, including two equations of state one radial and one tangential, and specified forms for the metric potentials. This approach yields explicit expressions for the energy density and the two scalar field coefficients. We then evaluate the model against physical requirements such as the regularity of the energy–momentum tensor components at the stellar center and verify that the mass function aligns with observations from the pulsar PSR J0740+6620. Finally, we analyze the mass–radius relation and apply best-fit techniques to the equations of state, confirming their consistency with the imposed assumptions.
{"title":"Two-scalar field stellar configurations in Einstein gravity","authors":"G.G.L. Nashed , A. Eid","doi":"10.1016/j.aop.2025.170294","DOIUrl":"10.1016/j.aop.2025.170294","url":null,"abstract":"<div><div>We develop a model of Einstein gravity coupled to two scalar fields that admits exact analytical solutions representing a realistic compact stellar object. To this end, we derive the equations of motion describing a spherically symmetric spacetime within this framework. The resulting system consists of three equations involving eight unknown functions: three associated with the scalar field coefficients, three arising from the energy–momentum tensor components, and two corresponding to the metric potentials. It is shown that one scalar field coefficient vanishes identically, reducing the number of unknowns to seven. To close the system, four additional constraints are imposed, including two equations of state one radial and one tangential, and specified forms for the metric potentials. This approach yields explicit expressions for the energy density and the two scalar field coefficients. We then evaluate the model against physical requirements such as the regularity of the energy–momentum tensor components at the stellar center and verify that the mass function aligns with observations from the pulsar PSR J0740+6620. Finally, we analyze the mass–radius relation and apply best-fit techniques to the equations of state, confirming their consistency with the imposed assumptions.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"485 ","pages":"Article 170294"},"PeriodicalIF":3.0,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145836664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2025-12-19DOI: 10.1016/j.aop.2025.170330
Mohammad Umar, Paramasivam Senthilkumaran
This paper investigates the rotational dynamics on the higher-order Poincaré sphere with the use of -plate by exploring three key aspects: the topological condition, the global-local rotation, and the SU(2) polarization evolution on the sphere. The polarized light beam corresponding to this sphere and -plates shares analogous topological features, characterized by azimuthal variation. We have formulated the topological condition that establishes a connection between the -plate and the higher-order Poincaré sphere, enabling the SU(2) polarization evolution on the same higher-order Poincaré sphere. Leveraging this correspondence, we have shown that a single global SO(3) rotation on the higher-order Poincaré sphere is a collection of multiple local SO(3) rotations on the standard Poincaré sphere. SO(3) is related to SU(2) through a two-to-one surjective homomorphism, with SU(2) serving as its double cover. Moreover, we demonstrate that a general -plate, defined by a continuously tunable retardance ranging from 0 to and an offset angle ranging from 0 to , provides the complete coverage on the higher-order Poincaré sphere. More importantly, by polarization evolution we mean that both the initial and final states belong to the same sphere, unlike the many existing methods that convert a homogeneous polarization state into a higher-order Poincaré sphere beams.
{"title":"SU(2) polarization evolution on higher-order Poincaré sphere by using general q-plate","authors":"Mohammad Umar, Paramasivam Senthilkumaran","doi":"10.1016/j.aop.2025.170330","DOIUrl":"10.1016/j.aop.2025.170330","url":null,"abstract":"<div><div>This paper investigates the rotational dynamics on the higher-order Poincaré sphere with the use of <span><math><mi>q</mi></math></span>-plate by exploring three key aspects: the topological condition, the global-local rotation, and the SU(2) polarization evolution on the sphere. The polarized light beam corresponding to this sphere and <span><math><mi>q</mi></math></span>-plates shares analogous topological features, characterized by azimuthal variation. We have formulated the topological condition that establishes a connection between the <span><math><mi>q</mi></math></span>-plate and the higher-order Poincaré sphere, enabling the SU(2) polarization evolution on the same higher-order Poincaré sphere. Leveraging this correspondence, we have shown that a single <em>global</em> SO(3) rotation on the higher-order Poincaré sphere is a collection of multiple <em>local</em> SO(3) rotations on the standard Poincaré sphere. SO(3) is related to SU(2) through a two-to-one surjective homomorphism, with SU(2) serving as its double cover. Moreover, we demonstrate that a general <span><math><mi>q</mi></math></span>-plate, defined by a continuously tunable retardance ranging from 0 to <span><math><mrow><mn>2</mn><mi>π</mi></mrow></math></span> and an offset angle ranging from 0 to <span><math><mrow><mi>π</mi><mo>/</mo><mn>2</mn></mrow></math></span>, provides the complete coverage on the higher-order Poincaré sphere. More importantly, by polarization evolution we mean that both the initial and final states belong to the same sphere, unlike the many existing methods that convert a homogeneous polarization state into a higher-order Poincaré sphere beams.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"486 ","pages":"Article 170330"},"PeriodicalIF":3.0,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145847627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号