Annals of Physics最新文献

{"title":"Improved coherence time of a non-Hermitian qubit in a PT-symmetric environment","authors":"Duttatreya ,&nbsp;Ipsika Mohanty ,&nbsp;Sanjib Dey","doi":"10.1016/j.aop.2025.170298","DOIUrl":"10.1016/j.aop.2025.170298","url":null,"abstract":"<div><div>Quantum computing’s potential for exponential speedup is fundamentally limited by decoherence, a phenomenon arising from environmental interactions. Non-Hermitian quantum mechanics, particularly <span><math><mrow><mi>P</mi><mi>T</mi></mrow></math></span>-symmetric systems, offers a novel framework for extending coherence times. This study examines a qubit’s coherence under non-Hermitian <span><math><mrow><mi>P</mi><mi>T</mi></mrow></math></span>-symmetric dynamics, highlighting significantly enhanced coherence times compared to Hermitian setups. The effect is especially pronounced when both the system and environment exhibit <span><math><mrow><mi>P</mi><mi>T</mi></mrow></math></span>-symmetry. Interestingly, greater environmental non-Hermiticity correlates with extended coherence, contrary to traditional expectations. These findings point to promising strategies for managing decoherence, which could significantly advance approaches to quantum information processing.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"484 ","pages":"Article 170298"},"PeriodicalIF":3.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145621590","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}

{"title":"Geometry-induced Coulomb-like potential in helically twisted quantum systems","authors":"Frankbelson dos S. Azevedo ,&nbsp;Faizuddin Ahmed ,&nbsp;Edilberto O. Silva","doi":"10.1016/j.aop.2025.170295","DOIUrl":"10.1016/j.aop.2025.170295","url":null,"abstract":"<div><div>In this paper, we investigate the Schrödinger equation in a three-dimensional helically twisted space characterized by a non-trivial torsion parameter. By applying exact separation of variables, we derive the radial equation governing the dynamics of quantum particles in this geometric background. Remarkably, the intrinsic coupling between angular and longitudinal momenta induced by the torsion gives rise to an attractive Coulomb-like potential term that emerges purely from the underlying geometry, without introducing any external fields or interactions. We obtain exact analytical solutions for the bound states, including both the energy spectrum and the normalized wave functions. Numerical calculations are also performed, and excellent agreement with the exact results is found. The interplay between the torsion parameter and the effective Coulomb-like interaction is analyzed in detail, revealing how geometric deformation gives rise to novel quantum confinement mechanisms in twisted spaces.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"484 ","pages":"Article 170295"},"PeriodicalIF":3.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577897","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}

{"title":"Structural evolution of gravastars under Tolman-IV metric in F(R,T) gravity","authors":"Arfa Waseem ,&nbsp;A. Eid ,&nbsp;Salma Yaqoob ,&nbsp;Faisal Javed","doi":"10.1016/j.aop.2025.170289","DOIUrl":"10.1016/j.aop.2025.170289","url":null,"abstract":"<div><div>This investigation provides a meticulous and profound analysis of gravastar configurations within the framework of <span><math><mrow><mi>F</mi><mrow><mo>(</mo><mi>R,T</mi><mo>)</mo></mrow></mrow></math></span> gravity, incorporating the Mazur Mottola formalism in conjunction with the temporal component of the Tolman-IV ansatz. The structure under consideration is delineated by a central region dominated by an exotic energy density, encased within an ultra-relativistic shell and culminating in a Schwarzschild exterior. Our treatment is anchored in the study of two gravastar models, uniquely distinguished by their respective mass–radius profiles. The analysis pursues a rigorous exploration of the shell’s internal features, with emphasis placed upon its finite thickness, energy density stratification and governing equation of state. The role of the coupling parameter <span><math><mi>α</mi></math></span> is examined within the domain <span><math><mrow><mn>0</mn><mo>≤</mo><mi>α</mi><mo>&lt;</mo><mn>1</mn></mrow></math></span>, wherein the limiting case <span><math><mrow><mi>α</mi><mo>→</mo><mn>0</mn></mrow></math></span> reproduces the conventional predictions of general relativity. In addition, a three-dimensional graphical exploration illustrates the stabilizing capacity of <span><math><mi>α</mi></math></span>, thereby consolidating the structural integrity and astrophysical viability of gravastars in the wider context of modified gravity frameworks.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"484 ","pages":"Article 170289"},"PeriodicalIF":3.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577953","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}

{"title":"Quantum steering and entanglement in two coupled harmonic oscillators","authors":"Radouan Hab arrih ,&nbsp;Ayoub Ghaba ,&nbsp;Pablo Díaz ,&nbsp;David Laroze ,&nbsp;Ahmed Jellal","doi":"10.1016/j.aop.2025.170306","DOIUrl":"10.1016/j.aop.2025.170306","url":null,"abstract":"<div><div>We study quantum steering and entanglement in two coupled harmonic oscillators using Wigner function techniques in phase space. We derive expressions for purity and quantum steering in the <span><math><mi>x</mi></math></span>- and <span><math><mi>y</mi></math></span>-directions. Our results extend previous studies from the weak coupling regime to the ultra-strong coupling regime, revealing significant deviations in behavior. In particular, we show that quantum steering between excited oscillators is completely absent even in the ultra-strong coupling regime. Similarly, resonant oscillators show no steering, and ground states cannot steer any receiver state. We find that quantum steering increases as the system approaches resonance and in certain ultra-strong coupling regimes. This behavior shows a clear asymmetry, with steering occurring in only one direction. It highlights the delicate balance of interaction strengths that shapes quantum correlations. These results improve our understanding of how excitation levels and coupling strengths affect quantum steering and entanglement in coupled harmonic oscillators.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"484 ","pages":"Article 170306"},"PeriodicalIF":3.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145621589","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}

{"title":"Reduced dynamics in quasi-Hermitian systems","authors":"Himanshu Badhani ,&nbsp;C.M. Chandrashekar","doi":"10.1016/j.aop.2025.170304","DOIUrl":"10.1016/j.aop.2025.170304","url":null,"abstract":"<div><div>Evolutions under non-Hermitian Hamiltonians with unbroken <span><math><mrow><mi>P</mi><mi>T</mi></mrow></math></span> symmetry can be considered unitary under appropriate choices of inner products, facilitated by the so-called metric operator. While it is understood that the choice of the metric operator has no bearing on the description of the system, in this work, we show that this choice does dictate the entanglement structure of the system. We show that the partial trace of the Hermitized density matrix gives the correct representation of the reduced subsystem, and based on such operations, we elucidate the metric dependency of the reduced dynamics and consequently the observable dependence of the subsystem decomposition. We use a non-Hermitian <span><math><mi>PT</mi></math></span>-symmetric quantum walk as a toy model to study this metric dependency, where we use the internal (coin state) as the subsystem of interest and study the coin-position entanglement and non-Markovianity of the coin dynamics.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"484 ","pages":"Article 170304"},"PeriodicalIF":3.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145621591","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}

{"title":"Quantum algorithm for testing graph completeness","authors":"Sara Giordano ,&nbsp;Miguel A. Martin-Delgado","doi":"10.1016/j.aop.2025.170305","DOIUrl":"10.1016/j.aop.2025.170305","url":null,"abstract":"<div><div>Testing graph completeness is a critical problem in computer science and network theory. Leveraging quantum computation, we present an efficient algorithm using the Szegedy quantum walk and quantum phase estimation (QPE). Our algorithm, which takes the number of nodes and the adjacency matrix as input, constructs a quantum walk operator and applies QPE to estimate its eigenvalues. These eigenvalues reveal the graph’s structural properties, enabling us to determine its completeness. We establish a relationship between the number of nodes in a complete graph and the number of marked nodes, optimizing the success probability and running time. The time complexity of our algorithm is <span><math><mrow><mi>O</mi><mrow><mo>(</mo><msup><mrow><mo>log</mo></mrow><mrow><mn>2</mn></mrow></msup><mi>n</mi><mo>)</mo></mrow></mrow></math></span>, where <span><math><mi>n</mi></math></span> is the number of nodes of the graph. offering a clear quantum advantage over classical methods. This approach is useful in network structure analysis, evaluating classical routing algorithms, and assessing systems based on pairwise comparisons.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"484 ","pages":"Article 170305"},"PeriodicalIF":3.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145621638","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}

{"title":"Strong gravitational lensing by black holes with a cloud of strings and constraints from EHT observations of M87* and Sgr A*","authors":"Arun Kumar ,&nbsp;Sushant G. Ghosh","doi":"10.1016/j.aop.2025.170291","DOIUrl":"10.1016/j.aop.2025.170291","url":null,"abstract":"<div><div>We investigate the strong gravitational lensing signatures of black holes (BH) surrounded by a novel class of cloud of strings (NCoS), characterized by additional parameters <span><math><mrow><mo>|</mo><mi>a</mi><mo>|</mo></mrow></math></span> and <span><math><msub><mrow><mi>c</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span> beyond the Schwarzschild case. After deriving the photon sphere and critical impact parameter, we investigate the deflection angle in the strong-field regime, showing logarithmic divergence near the photon orbit. The lensing observables—angular image positions (<span><math><msub><mrow><mi>θ</mi></mrow><mrow><mi>∞</mi></mrow></msub></math></span>), flux ratios (<span><math><msub><mrow><mi>r</mi></mrow><mrow><mtext>mag</mtext></mrow></msub></math></span>), and time delays between relativistic images—are computed for supermassive BHs M87<span><math><msup><mrow></mrow><mrow><mo>∗</mo></mrow></msup></math></span> and Sgr A<span><math><msup><mrow></mrow><mrow><mo>∗</mo></mrow></msup></math></span>. Compared to Schwarzschild, Reissner-Nordström, and Letelier BHs, NCoS spacetime reveals distinguishable lensing features, with photon sphere radii and Einstein ring diameters varying non-monotonically with <span><math><mrow><mo>|</mo><mi>a</mi><mo>|</mo></mrow></math></span> and <span><math><msub><mrow><mi>c</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span>. Applying our formalism to supermassive black holes M87* and Sgr A*, we find that the angular size of the photon ring <span><math><msub><mrow><mi>θ</mi></mrow><mrow><mi>∞</mi></mrow></msub></math></span> and flux ratio <span><math><msub><mrow><mi>r</mi></mrow><mrow><mtext>mag</mtext></mrow></msub></math></span> provide stringent constraints on the NCoS parameters. EHT observations of M87* restrict the string cloud parameter to <span><math><mrow><mn>0</mn><mo>≤</mo><mrow><mo>|</mo><mi>a</mi><mo>|</mo></mrow><mo>≤</mo><mn>0</mn><mo>.</mo><mn>56</mn></mrow></math></span>, while Sgr A* data impose tighter bounds (<span><math><mrow><mrow><mo>|</mo><mi>a</mi><mo>|</mo></mrow><mo>≤</mo><mn>0</mn><mo>.</mo><mn>42</mn></mrow></math></span>) with <span><math><mrow><msub><mrow><mi>c</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>/</mo><mi>M</mi><mo>≳</mo><mn>1</mn><mo>.</mo><mn>57</mn></mrow></math></span>, ruling out the pure Letelier limit (<span><math><mrow><msub><mrow><mi>c</mi></mrow><mrow><mn>0</mn></mrow></msub><mo>→</mo><mn>0</mn></mrow></math></span>) at <span><math><mrow><mo>&gt;</mo><mn>2</mn><mi>σ</mi></mrow></math></span> confidence. Our results illustrate that NCoS BHs reconcile with EHT observations for a broader parameter range than earlier models, offering a viable framework to probe string-inspired modifications to general relativity in the strong-gravity regime.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"484 ","pages":"Article 170291"},"PeriodicalIF":3.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577951","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}

{"title":"Dimensional phenomenology in polymeric quantization framework","authors":"Kourosh Nozari,&nbsp;Hamed Ramezani","doi":"10.1016/j.aop.2025.170297","DOIUrl":"10.1016/j.aop.2025.170297","url":null,"abstract":"<div><div>In this paper, we study the statistical mechanics within the polymer quantization framework in the semiclassical regime. We apply a non-canonical transformation to the phase space variables. Then, we use this non-canonical transformation to calculate the deformed density of states of the <span><math><mrow><mn>2</mn><mi>n</mi></mrow></math></span>-dimensional phase space, which encompasses all polymer effects. In the next step, some thermodynamic features of a system of <span><math><mi>n</mi></math></span>-dimensional harmonic oscillators are studied by computing the deformed partition function. The results show that the number of microstates decreases because there is an upper bound on the momentum within the polymer framework. We found that in the high-temperature regime, when the thermal de Broglie wavelength is close to the Planck length, <span><math><mi>n</mi></math></span> degrees of freedom of the system are frozen in this setup. In other words, there is an effective reduction in space dimensions from <span><math><mi>n</mi></math></span> to <span><math><mfrac><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></mfrac></math></span> in the polymeric framework, which also signals the fractional dimension for odd-dimensional oscillators.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"484 ","pages":"Article 170297"},"PeriodicalIF":3.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577898","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}

{"title":"Bipolaron in one-dimensional fermions with three-body interaction","authors":"O. Hryhorchak ,&nbsp;G. Panochko ,&nbsp;V. Pastukhov","doi":"10.1016/j.aop.2025.170296","DOIUrl":"10.1016/j.aop.2025.170296","url":null,"abstract":"<div><div>The properties of the one-dimensional <span><math><mrow><mi>S</mi><mi>U</mi><mrow><mo>(</mo><mn>3</mn><mo>)</mo></mrow></mrow></math></span> population-imbalanced fermions are discussed. First, the system is assumed to be in the two-body resonance where all two-body scattering lengths diverge, and the only interaction between fermions that is taken into account is the short-range three-body one. In particular, we consider the situation when only one ‘flavor’ of fermions is macroscopically occupied, and there are exactly two atoms of the other two. This system supports the trimer and the medium-induced dimer states studied here in detail and shows evidence of color superfluidity. The impact of the two-body inter-impurity interaction that breaks the initial <span><math><mrow><mi>S</mi><mi>U</mi><mrow><mo>(</mo><mn>3</mn><mo>)</mo></mrow></mrow></math></span> symmetry on the properties of the bipolaron is revealed.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"484 ","pages":"Article 170296"},"PeriodicalIF":3.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577952","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}

{"title":"Juggling with tensor bases in functional approaches","authors":"Jens Braun ,&nbsp;Andreas Geißel ,&nbsp;Jan M. Pawlowski ,&nbsp;Franz R. Sattler ,&nbsp;Nicolas Wink","doi":"10.1016/j.aop.2025.170250","DOIUrl":"10.1016/j.aop.2025.170250","url":null,"abstract":"<div><div>Systematic expansion schemes in functional approaches require the inclusion of non-classical tensor structures for relevant vertices. Each vertex has to be expanded in an appropriate tensor basis with a rapidly increasing number of basis elements. In contrast, classical actions typically only contain one of many tensor structures of a given vertex. Among the related tasks are the construction of bases and projection operators, the importance ordering of their elements, and the optimisation of such tensor bases, as well as an analysis of their regularity in momentum space. We present progress in all these directions and introduce the Mathematica package <span><span>TensorBases</span><svg><path></path></svg></span> designed for the aforementioned tasks.</div></div>","PeriodicalId":8249,"journal":{"name":"Annals of Physics","volume":"484 ","pages":"Article 170250"},"PeriodicalIF":3.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145577894","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}