Pub Date : 2026-01-22DOI: 10.1016/j.physa.2026.131312
Gianluca Di Natale , Francesco Pio De Cosmo , Leandro Cieri
Ice clouds, particularly cirrus, play a crucial role in Earth’s radiative balance, yet remain poorly represented in current climate models. A major source of uncertainty stems from the variability of their microphysical properties, especially the shape of ice crystals. In this paper, we propose a heuristic framework to describe the evolution of four main crystal habits — droxtals, plates, columns, and rosettes — commonly identified in situ observations and widely adopted in radiative transfer simulations. Rather than predicting the exact final morphology of individual crystals, our approach aims to assess the likelihood that, at a given time and under specified thermodynamic conditions, a crystal will most closely correspond to one of these canonical shapes used in cirrus modeling. In this study, we establish the theoretical foundations of this new approach by employing a non-Abelian gauge theory within a field-theoretical framework. Specifically, we impose an SU(2)U(1) symmetry on the fields associated with the probability of habit growth. This symmetry leads to a modified system of coupled Fokker–Planck equations, which capture the stochastic dynamics of ice crystal growth while incorporating phenomenological interactions among different habits. Our framework thus outlines a novel theoretical direction for integrating symmetry principles and field-theoretical tools into the modeling of habit dynamics in ice clouds. At this stage, numerical solutions of the proposed equations have not yet been implemented; developing and validating these with experimental data represents the next step of this research.
{"title":"Gauge theory approach to describe ice crystals habit evolution for ice clouds radiative transfer modeling","authors":"Gianluca Di Natale , Francesco Pio De Cosmo , Leandro Cieri","doi":"10.1016/j.physa.2026.131312","DOIUrl":"10.1016/j.physa.2026.131312","url":null,"abstract":"<div><div>Ice clouds, particularly cirrus, play a crucial role in Earth’s radiative balance, yet remain poorly represented in current climate models. A major source of uncertainty stems from the variability of their microphysical properties, especially the shape of ice crystals. In this paper, we propose a heuristic framework to describe the evolution of four main crystal habits — droxtals, plates, columns, and rosettes — commonly identified in situ observations and widely adopted in radiative transfer simulations. Rather than predicting the exact final morphology of individual crystals, our approach aims to assess the likelihood that, at a given time and under specified thermodynamic conditions, a crystal will most closely correspond to one of these canonical shapes used in cirrus modeling. In this study, we establish the theoretical foundations of this new approach by employing a non-Abelian gauge theory within a field-theoretical framework. Specifically, we impose an SU(2)<span><math><mo>⊗</mo></math></span>U(1) symmetry on the fields associated with the probability of habit growth. This symmetry leads to a modified system of coupled Fokker–Planck equations, which capture the stochastic dynamics of ice crystal growth while incorporating phenomenological interactions among different habits. Our framework thus outlines a novel theoretical direction for integrating symmetry principles and field-theoretical tools into the modeling of habit dynamics in ice clouds. At this stage, numerical solutions of the proposed equations have not yet been implemented; developing and validating these with experimental data represents the next step of this research.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"685 ","pages":"Article 131312"},"PeriodicalIF":3.1,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024809","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 : 2026-01-22DOI: 10.1016/j.physa.2026.131314
Henrique Santos Lima , Constantino Tsallis , Deniz Eroglu , Ugur Tirnakli
<div><div>Fourier’s law, which linearly relates heat flux to the negative gradient of temperature, is a fundamental principle in thermal physics and widely applied across materials science and engineering. However, its validity in low-dimensional systems with long-range interactions remains only partially understood. We investigate here the thermal transport along a one-dimensional chain of classical planar rotators with algebraically decaying interactions <span><math><mrow><mn>1</mn><mo>/</mo><msup><mrow><mi>r</mi></mrow><mrow><mi>α</mi></mrow></msup></mrow></math></span> with distance <span><math><mi>r</mi></math></span> (<span><math><mrow><mi>α</mi><mo>≥</mo><mn>0</mn></mrow></math></span>), known as the inertial <span><math><mi>α</mi></math></span>-XY model. Using nonequilibrium simulations with thermal reservoirs at the boundaries, we numerically study the thermal conductance <span><math><mi>σ</mi></math></span> as a function of system size <span><math><mi>L</mi></math></span>, temperature <span><math><mi>T</mi></math></span>, and <span><math><mi>α</mi></math></span>. We find that the results obey a universal scaling law characterized by a stretched <span><math><mi>q</mi></math></span>-exponential function with <span><math><mi>α</mi></math></span>-dependent parameters. Notably, a threshold at <span><math><mrow><msub><mrow><mi>α</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>≈</mo><mn>2</mn></mrow></math></span> separates two regimes: for <span><math><mrow><mi>α</mi><mo>≥</mo><msub><mrow><mi>α</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span>, Fourier’s law holds with size-independent conductivity <span><math><mrow><mi>κ</mi><mo>≡</mo><mi>L</mi><mi>σ</mi></mrow></math></span>, while for <span><math><mrow><mi>α</mi><mo><</mo><msub><mrow><mi>α</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span>, anomalous transport is observed, corroborating (with higher precision) the results reported in <span><span>Phys. Rev. E 94, 042117 (2016)</span><svg><path></path></svg></span>. These findings provide a quantitative framework for understanding the breakdown of Fourier’s law in systems with long-range interactions. The simulation is carried out by assuming the equations of motion, which include Langevin heat baths applied to the first and last particles, and are integrated using the Velocity Verlet algorithm. The conductance is calculated from the connection between Lagrangian heat flux and heat equation for typical values of <span><math><mrow><mo>(</mo><mi>α</mi><mo>,</mo><mi>T</mi><mo>,</mo><mi>L</mi><mo>)</mo></mrow></math></span>. For large <span><math><mi>L</mi></math></span>, the results can be collapsed into an universal <span><math><mi>q</mi></math></span>-stretched exponential form, namely <span><math><mrow><msup><mrow><mi>L</mi></mrow><mrow><msub><mrow><mi>δ</mi></mrow><mrow><mi>α</mi></mrow></msub></mrow></msup><mi>σ</mi><mo>∝</mo><msubsup><mrow><mi>e</mi></mrow><mrow><msub><mrow><mi>q</mi></mrow><mrow><mi>α</mi></mrow>
傅里叶定律将热通量与温度负梯度线性联系起来，是热物理中的一个基本原理，广泛应用于材料科学和工程领域。然而，它在具有远程相互作用的低维系统中的有效性仍然只是部分了解。本文研究了具有1/rα代数衰减相互作用且距离为r （α≥0）的经典平面旋转体一维链的热输运，称为惯性α- xy模型。利用边界处有热储层的非平衡模拟，我们数值研究了热导率σ作为系统尺寸L、温度T和α的函数。我们发现结果符合一个普遍的标度定律，其特征是具有α依赖参数的伸缩q指数函数。值得注意的是，αc≈2处的阈值分离了两种状态：对于α≥αc，傅里叶定律适用于与尺寸无关的电导率κ≡Lσ，而对于α<；αc，观察到异常输运，证实了（以更高的精度）在物理学中报道的结果。Rev. E 94,042117（2016）。这些发现为理解傅立叶定律在具有远程相互作用的系统中的分解提供了一个定量框架。模拟是通过假设运动方程进行的，其中包括应用于第一粒子和最后粒子的朗热浴，并使用Velocity Verlet算法进行积分。根据拉格朗日热流密度与典型值（α，T，L）的热方程之间的联系计算电导。对于大的L，结果可以坍缩成普遍的q-拉伸指数形式，即Lδασ∝eqα−Bα(Lγα t)ηα，其中eqz≡[1+(1−q)z]1/(1−q)。参数（γα、δα、Bα、ηα）均与α相关，qα为q-拉伸指数的指数。这种形式是可以实现的，因为ηα/(qα−1)之比相对于晶格尺寸l几乎是恒定的。这些发现为研究具有远程相互作用的系统的热传导机制提供了重要的见解。
{"title":"Fourier’s law breakdown for the planar-rotor chain with long-range interactions","authors":"Henrique Santos Lima , Constantino Tsallis , Deniz Eroglu , Ugur Tirnakli","doi":"10.1016/j.physa.2026.131314","DOIUrl":"10.1016/j.physa.2026.131314","url":null,"abstract":"<div><div>Fourier’s law, which linearly relates heat flux to the negative gradient of temperature, is a fundamental principle in thermal physics and widely applied across materials science and engineering. However, its validity in low-dimensional systems with long-range interactions remains only partially understood. We investigate here the thermal transport along a one-dimensional chain of classical planar rotators with algebraically decaying interactions <span><math><mrow><mn>1</mn><mo>/</mo><msup><mrow><mi>r</mi></mrow><mrow><mi>α</mi></mrow></msup></mrow></math></span> with distance <span><math><mi>r</mi></math></span> (<span><math><mrow><mi>α</mi><mo>≥</mo><mn>0</mn></mrow></math></span>), known as the inertial <span><math><mi>α</mi></math></span>-XY model. Using nonequilibrium simulations with thermal reservoirs at the boundaries, we numerically study the thermal conductance <span><math><mi>σ</mi></math></span> as a function of system size <span><math><mi>L</mi></math></span>, temperature <span><math><mi>T</mi></math></span>, and <span><math><mi>α</mi></math></span>. We find that the results obey a universal scaling law characterized by a stretched <span><math><mi>q</mi></math></span>-exponential function with <span><math><mi>α</mi></math></span>-dependent parameters. Notably, a threshold at <span><math><mrow><msub><mrow><mi>α</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>≈</mo><mn>2</mn></mrow></math></span> separates two regimes: for <span><math><mrow><mi>α</mi><mo>≥</mo><msub><mrow><mi>α</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span>, Fourier’s law holds with size-independent conductivity <span><math><mrow><mi>κ</mi><mo>≡</mo><mi>L</mi><mi>σ</mi></mrow></math></span>, while for <span><math><mrow><mi>α</mi><mo><</mo><msub><mrow><mi>α</mi></mrow><mrow><mi>c</mi></mrow></msub></mrow></math></span>, anomalous transport is observed, corroborating (with higher precision) the results reported in <span><span>Phys. Rev. E 94, 042117 (2016)</span><svg><path></path></svg></span>. These findings provide a quantitative framework for understanding the breakdown of Fourier’s law in systems with long-range interactions. The simulation is carried out by assuming the equations of motion, which include Langevin heat baths applied to the first and last particles, and are integrated using the Velocity Verlet algorithm. The conductance is calculated from the connection between Lagrangian heat flux and heat equation for typical values of <span><math><mrow><mo>(</mo><mi>α</mi><mo>,</mo><mi>T</mi><mo>,</mo><mi>L</mi><mo>)</mo></mrow></math></span>. For large <span><math><mi>L</mi></math></span>, the results can be collapsed into an universal <span><math><mi>q</mi></math></span>-stretched exponential form, namely <span><math><mrow><msup><mrow><mi>L</mi></mrow><mrow><msub><mrow><mi>δ</mi></mrow><mrow><mi>α</mi></mrow></msub></mrow></msup><mi>σ</mi><mo>∝</mo><msubsup><mrow><mi>e</mi></mrow><mrow><msub><mrow><mi>q</mi></mrow><mrow><mi>α</mi></mrow>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"685 ","pages":"Article 131314"},"PeriodicalIF":3.1,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024360","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 : 2026-01-22DOI: 10.1016/j.physa.2026.131320
Ronit D. Gross , Yanir Harel , Ido Kanter
The translation of written language has been known since the 3rd century BC; however, its necessity has become increasingly common in the information age. Today, many translators exist, based on encoder-decoder deep architectures, nevertheless, no quantitative objective methods are available to assess their performance, likely because the entropy of even a single language remains unknown. This study presents a quantitative method for estimating translation entropy, with the following key finding. Given a translator, several sentences that differ by only one selected token of a given pivot sentence yield identical translations. Analyzing the statistics of this phenomenon across an ensemble of such sentences, consisting each of a pivot selected token, yields the probabilities of replacing this specific token with others while preserving the translation. These probabilities constitute the entropy of the selected token, and the average across all selected pivot tokens provides an estimate of the translator’s overall translation entropy, which is decreased along the decoder blocks. This entropic measure allows for the quantitative ranking of several publicly available translators and reveals whether mutual translation entropy is symmetric. Extending the proposed method to include the replacement of two tokens in a given pivot sentence demonstrates a multiplicative effect, where translation degeneracy is proportional to the product of the degeneracies of the two tokens. These findings establish translation entropy as a measurable property and objective benchmarking of artificial translators. Results are based on MarianMT, T5-Base and NLLB-200 translators.
{"title":"Translation entropy: A statistical framework for evaluating translation systems","authors":"Ronit D. Gross , Yanir Harel , Ido Kanter","doi":"10.1016/j.physa.2026.131320","DOIUrl":"10.1016/j.physa.2026.131320","url":null,"abstract":"<div><div>The translation of written language has been known since the 3rd century BC; however, its necessity has become increasingly common in the information age. Today, many translators exist, based on encoder-decoder deep architectures, nevertheless, no quantitative objective methods are available to assess their performance, likely because the entropy of even a single language remains unknown. This study presents a quantitative method for estimating translation entropy, with the following key finding. Given a translator, several sentences that differ by only one selected token of a given pivot sentence yield identical translations. Analyzing the statistics of this phenomenon across an ensemble of such sentences, consisting each of a pivot selected token, yields the probabilities of replacing this specific token with others while preserving the translation. These probabilities constitute the entropy of the selected token, and the average across all selected pivot tokens provides an estimate of the translator’s overall translation entropy, which is decreased along the decoder blocks. This entropic measure allows for the quantitative ranking of several publicly available translators and reveals whether mutual translation entropy is symmetric. Extending the proposed method to include the replacement of two tokens in a given pivot sentence demonstrates a multiplicative effect, where translation degeneracy is proportional to the product of the degeneracies of the two tokens. These findings establish translation entropy as a measurable property and objective benchmarking of artificial translators. Results are based on MarianMT, T5-Base and NLLB-200 translators.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"686 ","pages":"Article 131320"},"PeriodicalIF":3.1,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081892","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 : 2026-01-21DOI: 10.1016/j.physa.2026.131315
Xuebing Gong
Spin orbit coupling (SOC) of the exciton induces the exciton fine structure, which holding significant potential in nanotechnology and optoelectronics. This paper theoretically examines exciton fine structure driven by SOC. The two bright excitons, interacting with photons, support three bound states: upper polariton (UP), middle polariton (MP), and lower polariton (LP), leading to Rabi oscillations and Schrödinger cat states between MP and LP. Moreover, the Kosterlitz-Thouless (KT) transition temperature of polaritons is enhanced by two difference bright excitons interaction. And the interactions between bright and dark excitons further recombine the MP, LP, and dark states into three energy branches. These findings advance understanding in quantum foundations, many-body physics, and quantum information.
{"title":"Fine structure of exciton: Schrödinger’s cat and superfluidity","authors":"Xuebing Gong","doi":"10.1016/j.physa.2026.131315","DOIUrl":"10.1016/j.physa.2026.131315","url":null,"abstract":"<div><div>Spin orbit coupling (SOC) of the exciton induces the exciton fine structure, which holding significant potential in nanotechnology and optoelectronics. This paper theoretically examines exciton fine structure driven by SOC. The two bright excitons, interacting with photons, support three bound states: upper polariton (UP), middle polariton (MP), and lower polariton (LP), leading to Rabi oscillations and Schrödinger cat states between MP and LP. Moreover, the Kosterlitz-Thouless (KT) transition temperature of polaritons is enhanced by two difference bright excitons interaction. And the interactions between bright and dark excitons further recombine the MP, LP, and dark states into three energy branches. These findings advance understanding in quantum foundations, many-body physics, and quantum information.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"686 ","pages":"Article 131315"},"PeriodicalIF":3.1,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081891","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 : 2026-01-21DOI: 10.1016/j.physa.2026.131311
Chunhua Hu, Wei Sheng
The kinetic theory is applied to investigate the impact mechanism of population mobility and urban resources on the evolution of city size distribution. The formation and transformation of city size are not the result of a single factor, but are influenced by multiple variables such as population mobility, resource endowments, and living environments. To systematically analyze the dynamic evolution law of city size distribution, we construct a Boltzmann model that integrates Markov transition probability and value function. This model not only incorporates the probability characteristics of population transfer between different cities (characterizing the randomness and directionality of population mobility), but also describes various factors that affect population migration by using a suitable value function, thus more accurately capturing the impact path of population migration behavior on city size. With the help of this Boltzmann model, we simulate and analyze the evolution process of city size distribution, ultimately revealing how population migration patterns and urban resource allocation interact to promote the specific evolution trend of city size distribution.
{"title":"Impact of population mobility and urban resource allocation on the size distribution of cities","authors":"Chunhua Hu, Wei Sheng","doi":"10.1016/j.physa.2026.131311","DOIUrl":"10.1016/j.physa.2026.131311","url":null,"abstract":"<div><div>The kinetic theory is applied to investigate the impact mechanism of population mobility and urban resources on the evolution of city size distribution. The formation and transformation of city size are not the result of a single factor, but are influenced by multiple variables such as population mobility, resource endowments, and living environments. To systematically analyze the dynamic evolution law of city size distribution, we construct a Boltzmann model that integrates Markov transition probability and value function. This model not only incorporates the probability characteristics of population transfer between different cities (characterizing the randomness and directionality of population mobility), but also describes various factors that affect population migration by using a suitable value function, thus more accurately capturing the impact path of population migration behavior on city size. With the help of this Boltzmann model, we simulate and analyze the evolution process of city size distribution, ultimately revealing how population migration patterns and urban resource allocation interact to promote the specific evolution trend of city size distribution.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"685 ","pages":"Article 131311"},"PeriodicalIF":3.1,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024363","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 : 2026-01-21DOI: 10.1016/j.physa.2026.131317
Leilei Shi, Cheng Zhang, Da-jun Zhang
The Nijhoff–Quispel–Capel (NQC) equation is a general lattice quadrilateral equation presented in terms of a function where and serve as extra parameters. It can be viewed as the counterpart of Q3 equation which is the second top equation in the Adler–Bobenko–Suris list. In this paper, we review some known formulations of the NQC variable , such as the Cauchy matrix approach and the eigenfunction approach via a spectral Wronskian. We also present a new perspective to formulate from the eigenfunctions of a Lax pair of the lattice (non-potential) modified Korteweg–de Vries equation. A new Dbar problem is introduced and employed in the derivation.
{"title":"On the formulation of the NQC variable","authors":"Leilei Shi, Cheng Zhang, Da-jun Zhang","doi":"10.1016/j.physa.2026.131317","DOIUrl":"10.1016/j.physa.2026.131317","url":null,"abstract":"<div><div>The Nijhoff–Quispel–Capel (NQC) equation is a general lattice quadrilateral equation presented in terms of a function <span><math><mrow><mi>S</mi><mrow><mo>(</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>)</mo></mrow></mrow></math></span> where <span><math><mi>a</mi></math></span> and <span><math><mi>b</mi></math></span> serve as extra parameters. It can be viewed as the counterpart of Q3 equation which is the second top equation in the Adler–Bobenko–Suris list. In this paper, we review some known formulations of the NQC variable <span><math><mrow><mi>S</mi><mrow><mo>(</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>)</mo></mrow></mrow></math></span>, such as the Cauchy matrix approach and the eigenfunction approach via a spectral Wronskian. We also present a new perspective to formulate <span><math><mrow><mi>S</mi><mrow><mo>(</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>)</mo></mrow></mrow></math></span> from the eigenfunctions of a Lax pair of the lattice (non-potential) modified Korteweg–de Vries equation. A new Dbar problem is introduced and employed in the derivation.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"685 ","pages":"Article 131317"},"PeriodicalIF":3.1,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024362","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 : 2026-01-20DOI: 10.1016/j.physa.2026.131275
Jinfeng Hu, Weiguo Song, Hang Yu, Xintong Li, Jinyao Ren, Jun Zhang
Building exits are critical bottlenecks during evacuation. In this study, the effects of obstacle number and placement near exits on pedestrian flow are studied. Evacuation experiments are conducted, and obstacle number and layout, as well as competitiveness level, are considered in different scenarios. Pedestrian trajectory data along with pressure measurements at the exit are analyzed to assess evacuation efficiency, collective movement patterns, and force distribution. The results indicate that the impact of obstacles depends on their number, placement, and the level of competitiveness. Under high-competition conditions, appropriately placed obstacles increase evacuation efficiency by up to 29.6 %, reduce collective lateral rushes by 49.9 %, and improve the global alignment parameter by 26 %. Pressure measurements further indicate that the forces exerted on the exit wall are reduced when obstacles are used at an appropriate position. Based on experimental and theoretical analysis, the mechanisms by which obstacles influence evacuation dynamics are elucidated. The study may provide empirical evidence for understanding crowd behavior and offer practical guidance for crowd management in high-density environments.
{"title":"Effects of obstacle number and layout on evacuation of high-density crowd at exits","authors":"Jinfeng Hu, Weiguo Song, Hang Yu, Xintong Li, Jinyao Ren, Jun Zhang","doi":"10.1016/j.physa.2026.131275","DOIUrl":"10.1016/j.physa.2026.131275","url":null,"abstract":"<div><div>Building exits are critical bottlenecks during evacuation. In this study, the effects of obstacle number and placement near exits on pedestrian flow are studied. Evacuation experiments are conducted, and obstacle number and layout, as well as competitiveness level, are considered in different scenarios. Pedestrian trajectory data along with pressure measurements at the exit are analyzed to assess evacuation efficiency, collective movement patterns, and force distribution. The results indicate that the impact of obstacles depends on their number, placement, and the level of competitiveness. Under high-competition conditions, appropriately placed obstacles increase evacuation efficiency by up to 29.6 %, reduce collective lateral rushes by 49.9 %, and improve the global alignment parameter by 26 %. Pressure measurements further indicate that the forces exerted on the exit wall are reduced when obstacles are used at an appropriate position. Based on experimental and theoretical analysis, the mechanisms by which obstacles influence evacuation dynamics are elucidated. The study may provide empirical evidence for understanding crowd behavior and offer practical guidance for crowd management in high-density environments.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"685 ","pages":"Article 131275"},"PeriodicalIF":3.1,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024808","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 : 2026-01-20DOI: 10.1016/j.physa.2026.131313
Yongjun Xiao , Aimei Liu , Li-Cai Zhao
The quantum thermodynamic performance of a Stirling cycle employing a three-spin Lipkin-Meshkov-Glick (LMG) model is investigated under varying magnetic interaction anisotropies and control parameters. The model operates in the anisotropic XY regime (), the Ising limit (), and the mixed ferromagnetic regime (), with key thermodynamic quantities evaluated across a range of temperature ratios, magnetic field strengths, and coupling asymmetries. The mean energy landscape reveals a strong dependence on the anisotropy parameter, highlighting quantum coherence effects and spin alignment. The operational phase space is mapped, showing distinct transitions between heat engine, refrigerator, and heater modes, with exhibiting the broadest mode diversity and yielding robust engine-like behavior. Thermodynamic quantities such as heat exchange and work output are analyzed, showing mode transitions driven by magnetic field tuning. Efficiency, refrigeration performance (ε), and the refined performance coefficient (Π) are presented, revealing intricate dependencies on system parameters. Anisotropic spin coupling is shown to enhance thermodynamic responsiveness, while strong magnetic fields induce saturation and performance decline due to level polarization. The results demonstrated that quantum many-body interactions, when properly tuned, could be harnessed to optimize the design of nanoscale heat engines, refrigerators, and other quantum thermal devices.
{"title":"Quantum stirling heat engines with a three-spin LMG model: Performance and thermodynamic modes under anisotropic coupling","authors":"Yongjun Xiao , Aimei Liu , Li-Cai Zhao","doi":"10.1016/j.physa.2026.131313","DOIUrl":"10.1016/j.physa.2026.131313","url":null,"abstract":"<div><div>The quantum thermodynamic performance of a Stirling cycle employing a three-spin Lipkin-Meshkov-Glick (LMG) model is investigated under varying magnetic interaction anisotropies and control parameters. The model operates in the anisotropic XY regime (<span><math><mrow><mi>γ</mi><mo>=</mo><mo>+</mo><mn>1</mn></mrow></math></span>), the Ising limit (<span><math><mrow><mi>γ</mi><mo>=</mo><mn>0</mn></mrow></math></span>), and the mixed ferromagnetic regime (<span><math><mrow><mi>γ</mi><mo>=</mo><mo>−</mo><mn>1</mn></mrow></math></span>), with key thermodynamic quantities evaluated across a range of temperature ratios, magnetic field strengths, and coupling asymmetries. The mean energy landscape reveals a strong dependence on the anisotropy parameter, highlighting quantum coherence effects and spin alignment. The operational phase space is mapped, showing distinct transitions between heat engine, refrigerator, and heater modes, with <span><math><mrow><mi>γ</mi><mo>=</mo><mo>+</mo><mn>1</mn></mrow></math></span> exhibiting the broadest mode diversity and <span><math><mrow><mi>γ</mi><mo>=</mo><mo>−</mo><mn>1</mn></mrow></math></span> yielding robust engine-like behavior. Thermodynamic quantities such as heat exchange and work output are analyzed, showing mode transitions driven by magnetic field tuning. Efficiency, refrigeration performance (ε), and the refined performance coefficient (Π) are presented, revealing intricate dependencies on system parameters. Anisotropic spin coupling is shown to enhance thermodynamic responsiveness, while strong magnetic fields induce saturation and performance decline due to level polarization. The results demonstrated that quantum many-body interactions, when properly tuned, could be harnessed to optimize the design of nanoscale heat engines, refrigerators, and other quantum thermal devices.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"686 ","pages":"Article 131313"},"PeriodicalIF":3.1,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081888","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 : 2026-01-19DOI: 10.1016/j.physa.2026.131310
M. Abdellaoui , S. Gaidi , A. Slaoui , R. Ahl Laamara
In this paper, we introduce a reliable method that uses linear entropy to analyze non-classical correlations in any qubit–qudit quantum state. This approach avoids the complex maximization of classical correlations required when using von Neumann entropy to calculate quantum discord. We then explore the dynamics of this quantum discord measure, as well as entanglement quantified via logarithmic negativity and measurement-induced disturbance, in qubit–qutrit systems under the influence of a non-Markovian dephasing channel with colored noise. Our results reveal how system parameters and noise properties influence the degradation of quantum correlations. Notably, we demonstrate the robustness of certain correlation measures under non-Markovian noise and emphasize the role of system dimensionality in maintaining quantum coherence. These findings offer valuable insights into the resilience of quantum correlations in noisy environments and open avenues for future research, such as extending the analysis to higher-dimensional systems or exploring other types of noise channels, thus contributing to the broader understanding of quantum systems in real-world applications.
{"title":"Linear quantum discord and entanglement in qubit–qutrit systems under Non-Markovian colored noise dephasing","authors":"M. Abdellaoui , S. Gaidi , A. Slaoui , R. Ahl Laamara","doi":"10.1016/j.physa.2026.131310","DOIUrl":"10.1016/j.physa.2026.131310","url":null,"abstract":"<div><div>In this paper, we introduce a reliable method that uses linear entropy to analyze non-classical correlations in any qubit–qudit quantum state. This approach avoids the complex maximization of classical correlations required when using von Neumann entropy to calculate quantum discord. We then explore the dynamics of this quantum discord measure, as well as entanglement quantified via logarithmic negativity and measurement-induced disturbance, in qubit–qutrit systems under the influence of a non-Markovian dephasing channel with colored noise. Our results reveal how system parameters and noise properties influence the degradation of quantum correlations. Notably, we demonstrate the robustness of certain correlation measures under non-Markovian noise and emphasize the role of system dimensionality in maintaining quantum coherence. These findings offer valuable insights into the resilience of quantum correlations in noisy environments and open avenues for future research, such as extending the analysis to higher-dimensional systems or exploring other types of noise channels, thus contributing to the broader understanding of quantum systems in real-world applications.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"685 ","pages":"Article 131310"},"PeriodicalIF":3.1,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024806","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 : 2026-01-19DOI: 10.1016/j.physa.2026.131309
Yihang Qin, Hao Chen, Lin Wang
Cooperation is a fundamental organizing principle in biological and social systems. However, under resource constraints, cooperative behavior often collapses as defectors always gain resources unilaterally in interactions. To address this, we propose a Forced Loner Mechanism (FLM) integrated into the Spatial Prisoner’s Dilemma with resource dynamics (SPDL), where bankrupt agents are forced to withdraw and receive a guaranteed subsidy. This mechanism models realistic social subsidies or industrial safety nets. Simulation results indicate that the forced loner mechanism restores cooperation under high temptation to defect. This mechanism significantly improves the overall performance of the game system by enhancing efficiency, sustainability, and fairness. These properties are quantified by three macroscopic indicators: net output, average cumulative resources, and the Gini coefficient, respectively. Moreover, a sensitivity analysis reveals that the mechanism is robust against variations in the Loner payoff. These findings provide a quantitative understanding of how social exit and protection mechanisms can be interventions to stabilize cooperation in resource-limited systems.
{"title":"Recovering cooperation in Spatial Prisoner’s Dilemma via a forced Loner mechanism","authors":"Yihang Qin, Hao Chen, Lin Wang","doi":"10.1016/j.physa.2026.131309","DOIUrl":"10.1016/j.physa.2026.131309","url":null,"abstract":"<div><div>Cooperation is a fundamental organizing principle in biological and social systems. However, under resource constraints, cooperative behavior often collapses as defectors always gain resources unilaterally in interactions. To address this, we propose a Forced Loner Mechanism (FLM) integrated into the Spatial Prisoner’s Dilemma with resource dynamics (SPDL), where bankrupt agents are forced to withdraw and receive a guaranteed subsidy. This mechanism models realistic social subsidies or industrial safety nets. Simulation results indicate that the forced loner mechanism restores cooperation under high temptation to defect. This mechanism significantly improves the overall performance of the game system by enhancing efficiency, sustainability, and fairness. These properties are quantified by three macroscopic indicators: net output, average cumulative resources, and the Gini coefficient, respectively. Moreover, a sensitivity analysis reveals that the mechanism is robust against variations in the Loner payoff. These findings provide a quantitative understanding of how social exit and protection mechanisms can be interventions to stabilize cooperation in resource-limited systems.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"685 ","pages":"Article 131309"},"PeriodicalIF":3.1,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146024364","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