Journal of Physics A: Mathematical and Theoretical最新文献_第10页

Ratchet-mediated resetting: current, efficiency, and exact solution 以棘轮为媒介的复位：电流、效率和精确解

IF 2.1 3区物理与天体物理

Journal of Physics A: Mathematical and Theoretical Pub Date : 2024-07-23 DOI: 10.1088/1751-8121/ad62c9

Connor Roberts, Emir Sezik and Eloise Lardet

引用次数: 0

The effect of Skyrme–Chern–Simons dynamics on gauged Skyrmions in 2+1 dimensions Skyrme-Chern-Simons 动力学对 2+1 维测量 Skyrmions 的影响

IF 2.1 3区物理与天体物理

Journal of Physics A: Mathematical and Theoretical Pub Date : 2024-07-23 DOI: 10.1088/1751-8121/ad61d4

Francisco Navarro-Lérida, Eugen Radu and D H Tchrakian

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Interference aided finite resonant response in an undamped forced oscillator 无阻尼强迫振荡器中的干涉辅助有限共振响应

IF 2.1 3区物理与天体物理

Journal of Physics A: Mathematical and Theoretical Pub Date : 2024-07-23 DOI: 10.1088/1751-8121/ad6412

Shihabul Haque and Jayanta K Bhattacharjee

{"title":"Interference aided finite resonant response in an undamped forced oscillator","authors":"Shihabul Haque and Jayanta K Bhattacharjee","doi":"10.1088/1751-8121/ad6412","DOIUrl":"https://doi.org/10.1088/1751-8121/ad6412","url":null,"abstract":"We apply perturbative techniques to a driven undamped sinusoidal oscillator at resonance. The angular displacement, θ, obeys the dynamics . The linearized approximation gives a divergent response (at long times) but the nonlinear terms make the response finite. We address the nonlinearity-induced finiteness in two ways by separately treating the short and long time scales. At long times, we use the traditional perturbative techniques to extract two drive dependent behaviours—one, the amplitude of oscillation scales as and, two, the time period of the slow mode varies as . For the early time behaviour, on the other hand, we devise an alternate perturbative expansion where the successive terms get larger with the order of evaluation but have alternating signs. The alternating signs (phase differences) between these terms leads to adestructive interference like effect. A careful consideration of this destructive interference like effect between successive terms leads to a finite response which describes the initial behaviour of the amplitude of the response reasonably correctly. We further note that for larger drive values, the system seems to undergo a first order transitional behaviour with a sudden jump in the largest Lyapunov exponent","PeriodicalId":16763,"journal":{"name":"Journal of Physics A: Mathematical and Theoretical","volume":"25 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141786204","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}

引用次数: 0

Algebraic formulas and geometric derivation of source identities 源等式的代数公式和几何推导

IF 2.1 3区物理与天体物理

Journal of Physics A: Mathematical and Theoretical Pub Date : 2024-07-23 DOI: 10.1088/1751-8121/ad62c8

Kohei Motegi and Ryo Ohkawa

引用次数: 0

The Unruh–DeWitt model and its joint interacting Hilbert space 恩鲁-德威特模型及其联合作用希尔伯特空间

IF 2.1 3区物理与天体物理

Journal of Physics A: Mathematical and Theoretical Pub Date : 2024-07-23 DOI: 10.1088/1751-8121/ad6365

Erickson Tjoa and Finnian Gray

{"title":"The Unruh–DeWitt model and its joint interacting Hilbert space","authors":"Erickson Tjoa and Finnian Gray","doi":"10.1088/1751-8121/ad6365","DOIUrl":"https://doi.org/10.1088/1751-8121/ad6365","url":null,"abstract":"In this work we make the connection between the Unruh–DeWitt (UDW) particle detector model applied to quantum field theory in curved spacetimes and the rigorous construction of the spin-boson (SB) model. With some modifications, we show that existing results about the existence of a SB ground state can be adapted to the UDW model. In the most relevant scenario involving massless scalar fields in (3+1)-dimensional globally hyperbolic spacetimes, where the UDW model describes a simplified model of light–matter interaction, we argue that common choices of the spacetime smearing functions regulate the ultraviolet behaviour of the model but can still exhibit infrared (IR) divergences. In particular, this implies the well-known expectation that the joint interacting Hilbert space of the model cannot be described by the tensor product of a two-dimensional complex Hilbert space and the Fock space of the vacuum representation. We discuss the conditions under which this problem does not arise and the relevance of the operator-algebraic approach for better understanding of particle detector models and their applications.Our work clarifies the connection between obstructions due to Haag’s theorem and IR bosons in the SB models, and paves the way for more rigorous study of entanglement and communication in the UDW framework involving multiple detectors.","PeriodicalId":16763,"journal":{"name":"Journal of Physics A: Mathematical and Theoretical","volume":"44 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141777069","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}

引用次数: 0

Multi-parameter quantum estimation of single- and two-mode pure Gaussian states 单模和双模纯高斯状态的多参数量子估算

IF 2.1 3区物理与天体物理

Journal of Physics A: Mathematical and Theoretical Pub Date : 2024-07-22 DOI: 10.1088/1751-8121/ad6364

Gabriele Bressanini, Marco G Genoni, M S Kim and Matteo G A Paris

引用次数: 0

Passive and active field theories for disease spreading 疾病传播的被动场和主动场理论

IF 2.1 3区物理与天体物理

Journal of Physics A: Mathematical and Theoretical Pub Date : 2024-07-21 DOI: 10.1088/1751-8121/ad4c31

Michael te Vrugt, Julian Jeggle and Raphael Wittkowski

{"title":"Passive and active field theories for disease spreading","authors":"Michael te Vrugt, Julian Jeggle and Raphael Wittkowski","doi":"10.1088/1751-8121/ad4c31","DOIUrl":"https://doi.org/10.1088/1751-8121/ad4c31","url":null,"abstract":"The worldwide COVID-19 pandemic has led to a significant growth of interest in the development of mathematical models that allow to describe effects such as social distancing measures, the development of vaccines, and mutations. Several of these models are based on concepts from soft matter theory. Considerably less well investigated is the reverse direction, i.e. how results from epidemiological research can be of interest for the physics of colloids and polymers. In this work, we consider the susceptible-infected-recovered (SIR)-dynamical density functional theory (DDFT) model, a combination of the SIR model from epidemiology with DDFT from nonequilibrium soft matter physics, which allows for an explicit modeling of social distancing. We extend the SIR-DDFT model both from an epidemiological perspective by incorporating vaccines, asymptomaticity, reinfections, and mutations, and from a soft matter perspective by incorporating noise and self-propulsion and by deriving a phase field crystal (PFC) model that allows for a simplified description. On this basis, we investigate via computer simulations how epidemiological models are affected by the presence of non-reciprocal interactions. This is done in a numerical study of a zombie outbreak.","PeriodicalId":16763,"journal":{"name":"Journal of Physics A: Mathematical and Theoretical","volume":"17 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141740040","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}

引用次数: 0

Non-ultralocal classical r-matrix structure for 1+1 field analogue of elliptic Calogero–Moser model 椭圆卡洛吉罗-莫泽模型 1+1 场类似物的非超局域经典 r 矩阵结构

IF 2.1 3区物理与天体物理

Journal of Physics A: Mathematical and Theoretical Pub Date : 2024-07-21 DOI: 10.1088/1751-8121/ad5ee1

Andrei Zotov

引用次数: 0

Front stability of infinitely steep travelling waves in population biology 群体生物学中无限陡峭行波的前稳定性

IF 2.1 3区物理与天体物理

Journal of Physics A: Mathematical and Theoretical Pub Date : 2024-07-21 DOI: 10.1088/1751-8121/ad6223

Matthew J Simpson, Nizhum Rahman and Alexander K Y Tam

{"title":"Front stability of infinitely steep travelling waves in population biology","authors":"Matthew J Simpson, Nizhum Rahman and Alexander K Y Tam","doi":"10.1088/1751-8121/ad6223","DOIUrl":"https://doi.org/10.1088/1751-8121/ad6223","url":null,"abstract":"Reaction–diffusion models are often used to describe biological invasion, where populations of individuals that undergo random motility and proliferation lead to moving fronts. Many reaction–diffusion models of biological invasion are extensions of the well–known Fisher–Kolmogorov–Petrovskii–Piskunov model that describes the spatiotemporal evolution of a 1D population density, , as a result of linear diffusion with flux , and logistic growth source term, . In 2020 Fadai introduced a new reaction–diffusion model of biological invasion with a nonlinear degenerate diffusive flux, , and the model was formulated as a moving boundary problem on , with and at (Fadai and Simpson 2020 J. Phys. A: Math. Theor. 53 095601). Fadai’s model leads to travelling wave solutions with infinitely steep, well–defined fronts at the moving boundary, and the model has the mathematical advantage of being analytically tractable in certain parameter limits. In this work we consider the stability of the travelling wave solutions presented by Fadai. We provide general insight by first presenting two key extensions of Fadai’s model by considering: (i) generalised nonlinear degenerate diffusion with flux for some constant m > 0; and, (ii) solutions describing both biological invasion with , and biological recession with . After establishing the existence of travelling wave solutions for these two extensions, our main contribution is to consider stability of the travelling wave solutions by introducing a lateral perturbation of the travelling wavefront. Full 2D time–dependent level–set numerical solutions indicate that invasive travelling waves are stable to small amplitude lateral perturbations, whereas receding travelling waves are unstable. These preliminary numerical observations are corroborated through a linear stability analysis that gives more formal insight into short time growth/decay of wavefront perturbation amplitude. Julia–based software, including level–set algorithms, is available on Github to replicate all results in this study.","PeriodicalId":16763,"journal":{"name":"Journal of Physics A: Mathematical and Theoretical","volume":"36 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141740043","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}

引用次数: 0

Coagulation-flocculation process on a lattice: Monte Carlo simulations 晶格上的混凝-絮凝过程：蒙特卡罗模拟

IF 2.1 3区物理与天体物理

Journal of Physics A: Mathematical and Theoretical Pub Date : 2024-07-18 DOI: 10.1088/1751-8121/ad5e4d

Viktoria Blavatska, Jaroslav Ilnytskyi and Erkki Lähderanta

{"title":"Coagulation-flocculation process on a lattice: Monte Carlo simulations","authors":"Viktoria Blavatska, Jaroslav Ilnytskyi and Erkki Lähderanta","doi":"10.1088/1751-8121/ad5e4d","DOIUrl":"https://doi.org/10.1088/1751-8121/ad5e4d","url":null,"abstract":"Coagulation-flocculation, the physicochemical process widely used for purification a wastewater, is affected both by chemical details of involved polymers and by the statistics of their conformations on a large scale. The latter aspect is covered in this study by employing a coarse-grained modeling approach based on a combination of two paradigms of statistical mechanics. One is the self-avoiding walk (SAW) which generates a range of conformations for a linear polymer of NSAW monomers. Another one is a non-trivial diffusion limited aggregation (DLA) process of NDLA impurities (referred thereafter as ‘particles’) which describes their coagulation occurring with the probability (p = 1 recovers a standard DLA). DLA of diffusive particles is complemented by their irreversible adsorption on the SAW monomers occurring with the probability equal to one, both processes resulting in formation of the DLA-SAW agglomerates. The dynamics of formation of such agglomerates, as well as their fractal dimensions and internal structure are of practical interest. We consider a range of related characteristics, such as: (i) absolute Na and relative na adsorbing efficiencies of SAW; (ii) effective gyration radius of the DLA-SAW agglomerates; and (iii) the fractal dimension of these aggregates. These are studied within a wide range for each parameter from a set .","PeriodicalId":16763,"journal":{"name":"Journal of Physics A: Mathematical and Theoretical","volume":"334 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141740042","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}

引用次数: 0