Pub Date : 2025-02-28DOI: 10.1016/j.physa.2025.130462
D.C.C. de Souza , P.D.S. de Lima , J.M. de Araújo , G. Corso
Time–frequency analysis methods are powerful for decoding signals with time-varying statistics and have applications in various scientific areas. By including the dominant frequency information in its convolution kernel, the W transform improves time–frequency resolution compared to the well-established Stockwell transform. However, the W transform is constructed from a Gaussian window function, which can limit its use for time series that are not concentrated in the harmonic domain. We generalize the W transform by introducing a finite-variance q-Gaussian distribution derived from the nonextensive statistical mechanics. The proposed q-Gaussian W transform has a free parameter to control the window function locality. We verify the time–frequency features of this new transform in two synthetic nonstationary signals and seismic field data as case points. We show that this non-Gaussian kernel with nonzero kurtosis improves the energy concentration of the time–frequency spectra.
{"title":"Time–frequency analysis with the q-Gaussian W transform","authors":"D.C.C. de Souza , P.D.S. de Lima , J.M. de Araújo , G. Corso","doi":"10.1016/j.physa.2025.130462","DOIUrl":"10.1016/j.physa.2025.130462","url":null,"abstract":"<div><div>Time–frequency analysis methods are powerful for decoding signals with time-varying statistics and have applications in various scientific areas. By including the dominant frequency information in its convolution kernel, the W transform improves time–frequency resolution compared to the well-established Stockwell transform. However, the W transform is constructed from a Gaussian window function, which can limit its use for time series that are not concentrated in the harmonic domain. We generalize the W transform by introducing a finite-variance <em>q</em>-Gaussian distribution derived from the nonextensive statistical mechanics. The proposed <em>q</em>-Gaussian W transform has a free parameter <span><math><mi>q</mi></math></span> to control the window function locality. We verify the time–frequency features of this new transform in two synthetic nonstationary signals and seismic field data as case points. We show that this non-Gaussian kernel with nonzero kurtosis improves the energy concentration of the time–frequency spectra.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"665 ","pages":"Article 130462"},"PeriodicalIF":2.8,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552959","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 : 2025-02-27DOI: 10.1016/j.physa.2025.130444
Yoshihiro Nishiyama
The two-dimensional (2D) quantum spin- model with the transverse-field , in-plane-anisotropy , and Dzyaloshinskii–Moriya (DM) interactions was investigated by means of the exact diagonalization method, which enables us to treat the -mediated complex-valued Hermitian matrix elements. According to the preceding real-space renormalization group analysis at , the -driven phase transition occurs generically for in contrast to the 1D model where both - and -induced phases are realized for and , respectively. In this paper, we evaluated the function , namely, the differential of with respect to the concerned energy scale, and from its behavior in proximity to , we observed an evidence of the -driven phase transition; additionally, ’s scaling dimension is estimated from ’s slope. It was also determined how the value of the DM interaction influences the order–disorder phase boundary around the multi-critical point, .
{"title":"Two-dimensional transverse-field XY model with the in-plane anisotropy and Dzyaloshinskii–Moriya interaction: Anisotropy-driven transition","authors":"Yoshihiro Nishiyama","doi":"10.1016/j.physa.2025.130444","DOIUrl":"10.1016/j.physa.2025.130444","url":null,"abstract":"<div><div>The two-dimensional (2D) quantum spin-<span><math><mrow><mi>S</mi><mo>=</mo><mn>1</mn><mo>/</mo><mn>2</mn></mrow></math></span> <span><math><mrow><mi>X</mi><mi>Y</mi></mrow></math></span> model with the transverse-field <span><math><mi>H</mi></math></span>, in-plane-anisotropy <span><math><mi>γ</mi></math></span>, and Dzyaloshinskii–Moriya (DM) <span><math><mi>D</mi></math></span> interactions was investigated by means of the exact diagonalization method, which enables us to treat the <span><math><mi>D</mi></math></span>-mediated complex-valued Hermitian matrix elements. According to the preceding real-space renormalization group analysis at <span><math><mrow><mi>H</mi><mo>=</mo><mn>0</mn></mrow></math></span>, the <span><math><mi>γ</mi></math></span>-driven phase transition occurs generically for <span><math><mrow><mi>D</mi><mo>≠</mo><mn>0</mn></mrow></math></span> in contrast to the 1D <span><math><mrow><mi>X</mi><mi>Y</mi></mrow></math></span> model where both <span><math><mi>γ</mi></math></span>- and <span><math><mi>D</mi></math></span>-induced phases are realized for <span><math><mrow><mi>γ</mi><mo>></mo><mi>D</mi></mrow></math></span> and <span><math><mrow><mi>γ</mi><mo><</mo><mi>D</mi></mrow></math></span>, respectively. In this paper, we evaluated the <span><math><mi>β</mi></math></span> function <span><math><mrow><mi>β</mi><mrow><mo>(</mo><mi>γ</mi><mo>)</mo></mrow></mrow></math></span>, namely, the differential of <span><math><mi>γ</mi></math></span> with respect to the concerned energy scale, and from its behavior in proximity to <span><math><mrow><mi>γ</mi><mo>=</mo><mn>0</mn></mrow></math></span>, we observed an evidence of the <span><math><mi>γ</mi></math></span>-driven phase transition; additionally, <span><math><mi>γ</mi></math></span>’s scaling dimension is estimated from <span><math><mrow><mi>β</mi><mrow><mo>(</mo><mi>γ</mi><mo>)</mo></mrow></mrow></math></span>’s slope. It was also determined how the value of the DM interaction influences the order–disorder phase boundary <span><math><mrow><msub><mrow><mi>H</mi></mrow><mrow><mi>c</mi></mrow></msub><mrow><mo>(</mo><mi>γ</mi><mo>)</mo></mrow></mrow></math></span> around the multi-critical point, <span><math><mrow><mi>γ</mi><mo>→</mo><mn>0</mn></mrow></math></span>.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"664 ","pages":"Article 130444"},"PeriodicalIF":2.8,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143527016","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 : 2025-02-26DOI: 10.1016/j.physa.2025.130488
Zuoan Hu , Shibo Wang , Yidong Wei , Jun Du , Tian Zeng
Rapid urbanization worldwide has led to a significant increase in the urban population, resulting in heightened pressure on urban pedestrian traffic systems. The recent Itaewon stampede, which occurred on a ramp, has drawn attention to the study of urban pedestrian transportation systems again. As a common mode of pedestrian traffic, there remains a lack of understanding regarding how crowd density and ramps impact pedestrian walking characteristics, specifically, the step length, step frequency, and step duration. To address this gap, we conducted a single-file pedestrian flow experiment with varying slope angles (0°, 3°, 5°, 7°, 9°, 12°, 17°,22°, 27°) to investigate the effects of slope angle and headway on stepping behaviors. Our main findings are as follows: The headway divides pedestrian stepping into free, weakly constrained, and strongly constrained regimes, with the headway thresholds for each regime being influenced by changes in slope angle. When walking under free conditions, whether uphill or downhill, pedestrians tend to increase their step length and decrease their step frequency on gentle slope angles (less than 5°). Additionally, for each slope angle, the step length and duration of uphill walking are greater than those of downhill walking; however, the step frequency during downhill walking is greater than that during uphill walking. Based on these findings, we have incorporated stepping behaviors into the social force model, allowing for the simultaneous reproduction of the primary dynamics and stepping characteristics of pedestrian flow. The model has been validated in a single-file flow scenario, demonstrating that the time-space diagram, fundamental diagram, step length-headway relation, and step frequency-headway relation of the simulation results closely align with experimental findings.
{"title":"Influence of slope angle and headway on the stepping behavior of single-file pedestrians: An experimental and modeling study","authors":"Zuoan Hu , Shibo Wang , Yidong Wei , Jun Du , Tian Zeng","doi":"10.1016/j.physa.2025.130488","DOIUrl":"10.1016/j.physa.2025.130488","url":null,"abstract":"<div><div>Rapid urbanization worldwide has led to a significant increase in the urban population, resulting in heightened pressure on urban pedestrian traffic systems. The recent Itaewon stampede, which occurred on a ramp, has drawn attention to the study of urban pedestrian transportation systems again. As a common mode of pedestrian traffic, there remains a lack of understanding regarding how crowd density and ramps impact pedestrian walking characteristics, specifically, the step length, step frequency, and step duration. To address this gap, we conducted a single-file pedestrian flow experiment with varying slope angles (0°, 3°, 5°, 7°, 9°, 12°, 17°,22°, 27°) to investigate the effects of slope angle and headway on stepping behaviors. Our main findings are as follows: The headway divides pedestrian stepping into free, weakly constrained, and strongly constrained regimes, with the headway thresholds for each regime being influenced by changes in slope angle. When walking under free conditions, whether uphill or downhill, pedestrians tend to increase their step length and decrease their step frequency on gentle slope angles (less than 5°). Additionally, for each slope angle, the step length and duration of uphill walking are greater than those of downhill walking; however, the step frequency during downhill walking is greater than that during uphill walking. Based on these findings, we have incorporated stepping behaviors into the social force model, allowing for the simultaneous reproduction of the primary dynamics and stepping characteristics of pedestrian flow. The model has been validated in a single-file flow scenario, demonstrating that the time-space diagram, fundamental diagram, step length-headway relation, and step frequency-headway relation of the simulation results closely align with experimental findings.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"665 ","pages":"Article 130488"},"PeriodicalIF":2.8,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552962","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 : 2025-02-26DOI: 10.1016/j.physa.2025.130489
Lin Li, Jingyu Lv, Jing Ruan, Lili Ma
In collective life, individuals find it difficult to avoid being influenced by their environment. In the spatial evolutionary game, the surrounding peers constitute the local environment of individuals. The difference in strategy from peers can make individuals feel pressure, which affects the evolution of cooperation by altering individuals’ behavioural decision-making. However, previous studies on the effects of peer pressure on cooperation have primarily focused on oversimplified network structures and assumed constant pressure sensitivity among all players, which has limited our understanding of the impact of peer pressure on the evolution of cooperation in more complex environments. This paper presents an evolutionary game model in which individual’s sensitivity to pressure is different from each other and dynamically adjusted with the change of strategies among the surroundings, capturing a more realistic portrayal of social influence and psychological factors. We examine how the dynamic sensitivities and the intensity of peer pressure affect the evolutionary dynamics by conducting the simulations on both Watts-Strogatz (WS) network and Barabási-Albert (BA) network. Our findings reveal that peer pressure with dynamic sensitivity exhibits completely different effects on cooperation for the WS and BA network, that is, it can greatly enhance cooperation on the WS network while inhibiting cooperation on the BA network. Besides, a lower level of pressure intensity can be more conductive to the evolution of cooperation, whether in WS network or BA network.
{"title":"The effects of dynamic peer pressure on the evolution of cooperation in complex networks","authors":"Lin Li, Jingyu Lv, Jing Ruan, Lili Ma","doi":"10.1016/j.physa.2025.130489","DOIUrl":"10.1016/j.physa.2025.130489","url":null,"abstract":"<div><div>In collective life, individuals find it difficult to avoid being influenced by their environment. In the spatial evolutionary game, the surrounding peers constitute the local environment of individuals. The difference in strategy from peers can make individuals feel pressure, which affects the evolution of cooperation by altering individuals’ behavioural decision-making. However, previous studies on the effects of peer pressure on cooperation have primarily focused on oversimplified network structures and assumed constant pressure sensitivity among all players, which has limited our understanding of the impact of peer pressure on the evolution of cooperation in more complex environments. This paper presents an evolutionary game model in which individual’s sensitivity to pressure is different from each other and dynamically adjusted with the change of strategies among the surroundings, capturing a more realistic portrayal of social influence and psychological factors. We examine how the dynamic sensitivities and the intensity of peer pressure affect the evolutionary dynamics by conducting the simulations on both Watts-Strogatz (WS) network and Barabási-Albert (BA) network. Our findings reveal that peer pressure with dynamic sensitivity exhibits completely different effects on cooperation for the WS and BA network, that is, it can greatly enhance cooperation on the WS network while inhibiting cooperation on the BA network. Besides, a lower level of pressure intensity can be more conductive to the evolution of cooperation, whether in WS network or BA network.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"665 ","pages":"Article 130489"},"PeriodicalIF":2.8,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552958","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 : 2025-02-25DOI: 10.1016/j.physa.2025.130427
Leonardo H.S. Fernandes , José R.A. Figueirôa , Caleb M.F. Martins , Adriel M.F. Martins
This research applies the Martins, Fernandes, and Nascimento (MFN) method for estimating statistical confidence intervals in information theory, focusing on two key quantifiers: Permutation entropy and Fisher information measure . Our study focuses on the daily closing price time series of five major cryptocurrencies — Bitcoin (BTC), Ethereum (ETH), BNB, Solana (SOL), and XRP — alongside two stock market indexes (S&P 500 and NYSE Composite), one commodity (Gold), and one exchange rate (EUR/USD). Based on the values of and , we construct the Shannon–Fisher Causality Plane (SFCP), which allows us to quantify disorder and evaluate randomness in the daily closing prices of various financial assets. Also, we provide novel insights related to the SFCP with density contours. Our findings reveal that XRP, BNB, and BTC are positioned close to the random ideal position on the SFCP, which suggests they exhibit higher disorder, lower predictability, greater informational efficiency, and reduced informational asymmetry and speculative activity. In contrast, the S&P 500, NYA, and Gold are positioned further from this ideal point, indicating increased market inefficiencies and speculation. Also, cryptocurrencies demonstrate less dense density contours with high and low , while traditional financial assets show denser contours with low and high . XRP, BNB, and BTC have less dense contours than other assets. The densest contours are observed for Gold, NYA, and S&P 500. Principal Component Analysis (PCA) supports these findings by confirming that cryptocurrencies, S&P 500 and Gold, function as safe-haven assets. Overall, the study highlights the potential of cryptocurrencies to provide more reliable investment signals, thereby mitigating risks associated with information asymmetry and speculative trading.
{"title":"The battle of informational efficiency: Cryptocurrencies vs. classical assets","authors":"Leonardo H.S. Fernandes , José R.A. Figueirôa , Caleb M.F. Martins , Adriel M.F. Martins","doi":"10.1016/j.physa.2025.130427","DOIUrl":"10.1016/j.physa.2025.130427","url":null,"abstract":"<div><div>This research applies the Martins, Fernandes, and Nascimento (MFN) method for estimating statistical confidence intervals in information theory, focusing on two key quantifiers: Permutation entropy <span><math><mrow><mo>(</mo><msub><mrow><mi>H</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>)</mo></mrow></math></span> and Fisher information measure <span><math><mrow><mo>(</mo><msub><mrow><mi>F</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>)</mo></mrow></math></span>. Our study focuses on the daily closing price time series of five major cryptocurrencies — Bitcoin (BTC), Ethereum (ETH), BNB, Solana (SOL), and XRP — alongside two stock market indexes (S&P 500 and NYSE Composite), one commodity (Gold), and one exchange rate (EUR/USD). Based on the values of <span><math><msub><mrow><mi>H</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>s</mi></mrow></msub></math></span>, we construct the Shannon–Fisher Causality Plane (SFCP), which allows us to quantify disorder and evaluate randomness in the daily closing prices of various financial assets. Also, we provide novel insights related to the SFCP with density contours. Our findings reveal that XRP, BNB, and BTC are positioned close to the random ideal position <span><math><mfenced><mrow><msub><mrow><mi>H</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>=</mo><mn>1</mn><mo>,</mo><msub><mrow><mi>F</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>=</mo><mn>0</mn></mrow></mfenced></math></span> on the SFCP, which suggests they exhibit higher disorder, lower predictability, greater informational efficiency, and reduced informational asymmetry and speculative activity. In contrast, the S&P 500, NYA, and Gold are positioned further from this ideal point, indicating increased market inefficiencies and speculation. Also, cryptocurrencies demonstrate less dense density contours with high <span><math><mrow><mo>(</mo><msub><mrow><mi>H</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>)</mo></mrow></math></span> and low <span><math><mrow><mo>(</mo><msub><mrow><mi>F</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>)</mo></mrow></math></span>, while traditional financial assets show denser contours with low <span><math><mrow><mo>(</mo><msub><mrow><mi>H</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>)</mo></mrow></math></span> and high <span><math><mrow><mo>(</mo><msub><mrow><mi>F</mi></mrow><mrow><mi>s</mi></mrow></msub><mo>)</mo></mrow></math></span>. XRP, BNB, and BTC have less dense contours than other assets. The densest contours are observed for Gold, NYA, and S&P 500. Principal Component Analysis (PCA) supports these findings by confirming that cryptocurrencies, S&P 500 and Gold, function as safe-haven assets. Overall, the study highlights the potential of cryptocurrencies to provide more reliable investment signals, thereby mitigating risks associated with information asymmetry and speculative trading.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"664 ","pages":"Article 130427"},"PeriodicalIF":2.8,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511074","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 : 2025-02-25DOI: 10.1016/j.physa.2025.130479
Kang Du , Ruguo Fan , Dongxue Wang , Xiao Xie , Xiaoxia Xu , Jinchai Lin
With the widespread use of social media in modern society, the impact of rumor propagation on public opinion and social stability has become increasingly prominent. Investigating the dynamics of rumor propagation is crucial for developing effective rumor control strategies and mitigating the harmful effects of rumors. However, existing studies primarily focus on the effects of individual or media debunking mechanisms within a single-layer network framework, often assuming uniform time lag effects across different propagating entities and processes. To address these gaps, this paper aims to comprehensively examine both debunking mechanisms, along with different types of time lag effects arising from information collection, transmission, and clarification processes, to investigate how rumors and counter-rumors interact and spread within two-layer networks. We first develop a new rumor spreading model, the XYZ-SIDR model, which consists of seven states: susceptible, debunking, and removed media, as well as susceptible, infected, debunking, and removed individuals. We then calculate the basic reproduction number and establish the local and global asymptotic stability of the model’s equilibrium points. Similarly, we construct and analyze an SIDR spreading system without the media debunking mechanism, which serves as a comparison to understand the impact of the media debunking mechanism on rumor propagation. Additionally, we examine the XYZ-SIDR spreading system with different time lags, allowing us to explore the influence of time lags on rumor propagation. Finally, the stability of the XYZ-SIDR model is verified using numerical simulations, key factors influencing rumor propagation are explored, and a comparative analysis of the XYZ-SIDR model with the SIDR and SIR models is conducted.
{"title":"Competitive information spreading model in two-layer networks considering dual debunking mechanisms and time lag effects","authors":"Kang Du , Ruguo Fan , Dongxue Wang , Xiao Xie , Xiaoxia Xu , Jinchai Lin","doi":"10.1016/j.physa.2025.130479","DOIUrl":"10.1016/j.physa.2025.130479","url":null,"abstract":"<div><div>With the widespread use of social media in modern society, the impact of rumor propagation on public opinion and social stability has become increasingly prominent. Investigating the dynamics of rumor propagation is crucial for developing effective rumor control strategies and mitigating the harmful effects of rumors. However, existing studies primarily focus on the effects of individual or media debunking mechanisms within a single-layer network framework, often assuming uniform time lag effects across different propagating entities and processes. To address these gaps, this paper aims to comprehensively examine both debunking mechanisms, along with different types of time lag effects arising from information collection, transmission, and clarification processes, to investigate how rumors and counter-rumors interact and spread within two-layer networks. We first develop a new rumor spreading model, the XYZ-SIDR model, which consists of seven states: susceptible, debunking, and removed media, as well as susceptible, infected, debunking, and removed individuals. We then calculate the basic reproduction number and establish the local and global asymptotic stability of the model’s equilibrium points. Similarly, we construct and analyze an SIDR spreading system without the media debunking mechanism, which serves as a comparison to understand the impact of the media debunking mechanism on rumor propagation. Additionally, we examine the XYZ-SIDR spreading system with different time lags, allowing us to explore the influence of time lags on rumor propagation. Finally, the stability of the XYZ-SIDR model is verified using numerical simulations, key factors influencing rumor propagation are explored, and a comparative analysis of the XYZ-SIDR model with the SIDR and SIR models is conducted.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"665 ","pages":"Article 130479"},"PeriodicalIF":2.8,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143552963","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 : 2025-02-24DOI: 10.1016/j.physa.2025.130463
Wen-Rui Sun, Xu Qiu, Ai-Yuan Hu
<div><div>We investigate the magnetic properties of the compound MnF <span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> by means of the double-time Green<span><math><msup><mrow></mrow><mrow><mo>′</mo></mrow></msup></math></span>s function method. Using the Tyablikov decoupling approximation, we derive analytical expressions for the system<span><math><msup><mrow></mrow><mrow><mo>′</mo></mrow></msup></math></span>s phase transition temperature <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub></math></span>, the magnetic susceptibility at the phase transition point <span><math><mrow><mi>χ</mi><mrow><mo>(</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span> under zero field, and the Curie–Weiss temperature <span><math><mi>θ</mi></math></span>. In principle, any two of them can be used to determine the nearest-neighbor <span><math><msub><mrow><mi>J</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> and next-nearest-neighbor <span><math><msub><mrow><mi>J</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> in terms of the experimentally measured <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub></math></span>, <span><math><mrow><mi>χ</mi><mrow><mo>(</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span> and <span><math><mi>θ</mi></math></span>. All three possible combinations are tested: using <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub></math></span> and <span><math><mrow><mi>χ</mi><mrow><mo>(</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span> are named as scenario I, <span><math><mrow><mi>χ</mi><mrow><mo>(</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span> and <span><math><mi>θ</mi></math></span> named as scenario II, and <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub></math></span> and <span><math><mi>θ</mi></math></span> named as scenario III. Fitting experimental data shows that the results of scenario I are in good agreement with the experiment, indicating that it is reasonable to use <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub></math></span> and <span><math><mrow><mi>χ</mi><mrow><mo>(</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span> to determine the values of <span><math><msub><mrow><mi>J</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>J</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>. At the same time, the rationality of these three physical quantities in determining the values of <span><math><msub><mrow><mi>J</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>J</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> is demonstrated, and the conclusion is that: wh
{"title":"Calculating the exchange interaction parameters between spins in MnF2 compound by Green’s function method","authors":"Wen-Rui Sun, Xu Qiu, Ai-Yuan Hu","doi":"10.1016/j.physa.2025.130463","DOIUrl":"10.1016/j.physa.2025.130463","url":null,"abstract":"<div><div>We investigate the magnetic properties of the compound MnF <span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> by means of the double-time Green<span><math><msup><mrow></mrow><mrow><mo>′</mo></mrow></msup></math></span>s function method. Using the Tyablikov decoupling approximation, we derive analytical expressions for the system<span><math><msup><mrow></mrow><mrow><mo>′</mo></mrow></msup></math></span>s phase transition temperature <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub></math></span>, the magnetic susceptibility at the phase transition point <span><math><mrow><mi>χ</mi><mrow><mo>(</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span> under zero field, and the Curie–Weiss temperature <span><math><mi>θ</mi></math></span>. In principle, any two of them can be used to determine the nearest-neighbor <span><math><msub><mrow><mi>J</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> and next-nearest-neighbor <span><math><msub><mrow><mi>J</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> in terms of the experimentally measured <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub></math></span>, <span><math><mrow><mi>χ</mi><mrow><mo>(</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span> and <span><math><mi>θ</mi></math></span>. All three possible combinations are tested: using <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub></math></span> and <span><math><mrow><mi>χ</mi><mrow><mo>(</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span> are named as scenario I, <span><math><mrow><mi>χ</mi><mrow><mo>(</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span> and <span><math><mi>θ</mi></math></span> named as scenario II, and <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub></math></span> and <span><math><mi>θ</mi></math></span> named as scenario III. Fitting experimental data shows that the results of scenario I are in good agreement with the experiment, indicating that it is reasonable to use <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub></math></span> and <span><math><mrow><mi>χ</mi><mrow><mo>(</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>N</mi></mrow></msub><mo>)</mo></mrow></mrow></math></span> to determine the values of <span><math><msub><mrow><mi>J</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>J</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>. At the same time, the rationality of these three physical quantities in determining the values of <span><math><msub><mrow><mi>J</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>J</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> is demonstrated, and the conclusion is that: wh","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"664 ","pages":"Article 130463"},"PeriodicalIF":2.8,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511077","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 : 2025-02-24DOI: 10.1016/j.physa.2025.130470
Guozhu Cheng, Fengwei Meng, Jiale Lv, Yongsheng Chen, Cong Xi
Urban expressways are critical components of transportation networks, playing a key role in improving traffic flow and mitigating congestion. This study investigates traffic flow simulations in urban expressway merging areas to ensure efficient, safe, and seamless driving for connected and autonomous vehicles (CAVs). The merging area is systematically divided into zones, with tailored car-following and lane-changing rules developed for CAVs and human-driven vehicles (HDVs) to capture their distinct behavioral characteristics. A CAV-oriented cellular automata (CA) model, integrating dynamic safety spacing and interconnectivity, is proposed to evaluate the effects of CAV penetration rates on traffic efficiency and safety. The results demonstrate that higher CAV penetration rates significantly enhance outflow volumes, particularly under medium to high traffic conditions. Analysis using the Average Travel Time (ATT) metric underscores substantial efficiency improvements facilitated by CAVs, while the Lane Change Time to Collision (LCTTC) metric highlights their contribution to improved safety in congested scenarios. Furthermore, increased CAV penetration rates effectively mitigate traffic flow disruptions caused by stochastic slowing behavior, enhancing overall system stability. The proposed model provides a comprehensive framework for analyzing lane-changing dynamics and operational risks in merging areas, offering valuable insights for traffic management and the strategic deployment of CAV technologies.
{"title":"Dynamic zonal modeling and connectivity: Enhancing safety and efficiency in merging zones","authors":"Guozhu Cheng, Fengwei Meng, Jiale Lv, Yongsheng Chen, Cong Xi","doi":"10.1016/j.physa.2025.130470","DOIUrl":"10.1016/j.physa.2025.130470","url":null,"abstract":"<div><div>Urban expressways are critical components of transportation networks, playing a key role in improving traffic flow and mitigating congestion. This study investigates traffic flow simulations in urban expressway merging areas to ensure efficient, safe, and seamless driving for connected and autonomous vehicles (CAVs). The merging area is systematically divided into zones, with tailored car-following and lane-changing rules developed for CAVs and human-driven vehicles (HDVs) to capture their distinct behavioral characteristics. A CAV-oriented cellular automata (CA) model, integrating dynamic safety spacing and interconnectivity, is proposed to evaluate the effects of CAV penetration rates on traffic efficiency and safety. The results demonstrate that higher CAV penetration rates significantly enhance outflow volumes, particularly under medium to high traffic conditions. Analysis using the Average Travel Time (ATT) metric underscores substantial efficiency improvements facilitated by CAVs, while the Lane Change Time to Collision (LCTTC) metric highlights their contribution to improved safety in congested scenarios. Furthermore, increased CAV penetration rates effectively mitigate traffic flow disruptions caused by stochastic slowing behavior, enhancing overall system stability. The proposed model provides a comprehensive framework for analyzing lane-changing dynamics and operational risks in merging areas, offering valuable insights for traffic management and the strategic deployment of CAV technologies.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"664 ","pages":"Article 130470"},"PeriodicalIF":2.8,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143518894","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 : 2025-02-24DOI: 10.1016/j.physa.2025.130464
H. Vargová , J. Strečka
The genuine tetrapartite entanglement of a quantum mixed spin-(1/2,1) Heisenberg tetramer is quantified according to the three different approaches incorporated all seven global bisections existing within the tetrapartite system. The degree of an entanglement of each bisection is evaluated through the bipartite negativity at zero- and non-zero temperature taking into account ferromagnetic as well as antiferromagnetic type of intra- () and inter-dimer () exchange coupling inside the square plaquette. Three utilized quantification methods based on the generalization of (i) a genuine tripartite negativity, (ii) a Coffman, Kundu and Wootters monogamy relation and (iii) a geometric average of complete trisections, result to the qualitatively and almost quantitatively identical behavior of a genuine tetrapartite negativity. It is shown that the genuine tetrapartite negativity exclusively arises from the antiferromagnetic-inter dimer coupling, whereas the character of with respect to ( or ) determines its zero-temperature magnitude as well as its thermal stability with respect to the magnetic field and temperature. As is demonstrated for the genuine tetrapartite negativity is dramatically reduced due to the preference of magnetic arrangement involving two separable mixed spin-(1/2,1) dimers. In an opposite limit the genuine tetrapartite negativity is significantly stable with a threshold temperature proportional to the strength of an inter-dimer coupling . It is found, that all three quantification procedures are insufficient to correctly describe the genuine tetrapartite negativity in a specific part of the parameter space with absence of relevant dimer separable states. Finally, the thermal stability of a genuine tetrapartite negativity is discussed in detail for selected geometries motivated by the real tetranuclear bimetallic complexes with a CuNi magnetic core.
{"title":"The quantification of a genuine tetrapartite entanglement in a mixed spin-(1/2,1) Heisenberg tetramer","authors":"H. Vargová , J. Strečka","doi":"10.1016/j.physa.2025.130464","DOIUrl":"10.1016/j.physa.2025.130464","url":null,"abstract":"<div><div>The genuine tetrapartite entanglement of a quantum mixed spin-(1/2,1) Heisenberg tetramer is quantified according to the three different approaches incorporated all seven global bisections existing within the tetrapartite system. The degree of an entanglement of each bisection is evaluated through the bipartite negativity at zero- and non-zero temperature taking into account ferromagnetic as well as antiferromagnetic type of intra- (<span><math><mi>J</mi></math></span>) and inter-dimer (<span><math><msub><mrow><mi>J</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span>) exchange coupling inside the square plaquette. Three utilized quantification methods based on the generalization of (i) a genuine tripartite negativity, (ii) a Coffman, Kundu and Wootters monogamy relation and (iii) a geometric average of complete trisections, result to the qualitatively and almost quantitatively identical behavior of a genuine tetrapartite negativity. It is shown that the genuine tetrapartite negativity exclusively arises from the antiferromagnetic-inter dimer <span><math><mrow><msub><mrow><mi>J</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>></mo><mn>0</mn></mrow></math></span> coupling, whereas the character of with respect to <span><math><mi>J</mi></math></span> (<span><math><mrow><mi>J</mi><mo>></mo><mn>0</mn></mrow></math></span> or <span><math><mrow><mi>J</mi><mo><</mo><mn>0</mn></mrow></math></span>) determines its zero-temperature magnitude as well as its thermal stability with respect to the magnetic field and temperature. As is demonstrated for <span><math><mrow><mn>0</mn><mo><</mo><msub><mrow><mi>J</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>/</mo><mi>J</mi><mo><</mo><mn>1</mn></mrow></math></span> the genuine tetrapartite negativity is dramatically reduced due to the preference of magnetic arrangement involving two separable mixed spin-(1/2,1) dimers. In an opposite limit the genuine tetrapartite negativity is significantly stable with a threshold temperature proportional to the strength of an inter-dimer coupling <span><math><msub><mrow><mi>J</mi></mrow><mrow><mn>1</mn></mrow></msub></math></span>. It is found, that all three quantification procedures are insufficient to correctly describe the genuine tetrapartite negativity in a specific part of the parameter space with absence of relevant dimer separable states. Finally, the thermal stability of a genuine tetrapartite negativity is discussed in detail for selected geometries motivated by the real tetranuclear bimetallic complexes with a Cu<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Ni<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> magnetic core.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"664 ","pages":"Article 130464"},"PeriodicalIF":2.8,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143529416","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}
With the emergence and development of connected and autonomous driving technologies, managing the behavior of connected autonomous vehicles (CAVs) within mixed traffic flow can mitigate traffic oscillation and enhance overall traffic performance. In recent years, the congestion absorption strategy known as jam-absorption driving (JAD) has been proposed, demonstrating efficacy in absorbing motion waves. Based on this premise, the paper addresses congestion phenomena on roadways by utilizing the real-time control system for JAD within a localized mixed traffic environment of CAVs. This system detects and locates the formation of mobile motion waves, estimates their starting and ending points, selects appropriate CAVs to serve as absorbing vehicles, and issues commands to activate them while choosing suitable control modes to facilitate the absorption of motion waves. Finally, simulations employing a stochastic car-following model are conducted to replicate experimental traffic phenomena and outcomes, testing the real-time absorption effects of varying absorption speeds on motion waves. The results indicate that the JAD system effectively eliminates both single and double motion waves observed during the experiments. In the analysis of individual motion wave, the application of the JAD system resulted in reductions in average speed, speed standard deviation, and speed variability, with speed variability decreasing by as much as 16.22 %. In terms of vehicle collision risk, compared to before the implementation of the JAD system, the platoon's TET and TIT values decreased by 15.45 % and 15.77 % respectively. Regarding energy consumption, the maximum reduction was 6.51 % at a speed of 12.5 m/s. As for emission, CO2 emission decreased by up to 25.05 %, NOx emission by 30.30 %, VOCx emission by 1.63 g/km, and PM emission by 31.53 %.These findings validate that the JAD system effectively mitigates motion waves and reduces traffic oscillations by experimental data, thereby enhancing the efficiency of mixed traffic flow and improving roadway safety.
{"title":"The elimination and absorption mechanism of oscillatory motion wave based on jam-absorption driving for mixed traffic flow in intelligent connected environment","authors":"Jin Shen , Jiandong Zhao , Zhixin Yu , Shiteng Zheng , Rui Jiang","doi":"10.1016/j.physa.2025.130485","DOIUrl":"10.1016/j.physa.2025.130485","url":null,"abstract":"<div><div>With the emergence and development of connected and autonomous driving technologies, managing the behavior of connected autonomous vehicles (CAVs) within mixed traffic flow can mitigate traffic oscillation and enhance overall traffic performance. In recent years, the congestion absorption strategy known as jam-absorption driving (JAD) has been proposed, demonstrating efficacy in absorbing motion waves. Based on this premise, the paper addresses congestion phenomena on roadways by utilizing the real-time control system for JAD within a localized mixed traffic environment of CAVs. This system detects and locates the formation of mobile motion waves, estimates their starting and ending points, selects appropriate CAVs to serve as absorbing vehicles, and issues commands to activate them while choosing suitable control modes to facilitate the absorption of motion waves. Finally, simulations employing a stochastic car-following model are conducted to replicate experimental traffic phenomena and outcomes, testing the real-time absorption effects of varying absorption speeds on motion waves. The results indicate that the JAD system effectively eliminates both single and double motion waves observed during the experiments. In the analysis of individual motion wave, the application of the JAD system resulted in reductions in average speed, speed standard deviation, and speed variability, with speed variability decreasing by as much as 16.22 %. In terms of vehicle collision risk, compared to before the implementation of the JAD system, the platoon's TET and TIT values decreased by 15.45 % and 15.77 % respectively. Regarding energy consumption, the maximum reduction was 6.51 % at a speed of 12.5 m/s. As for emission, CO<sub>2</sub> emission decreased by up to 25.05 %, NO<sub>x</sub> emission by 30.30 %, VOC<sub>x</sub> emission by 1.63 g/km, and PM emission by 31.53 %.These findings validate that the JAD system effectively mitigates motion waves and reduces traffic oscillations by experimental data, thereby enhancing the efficiency of mixed traffic flow and improving roadway safety.</div></div>","PeriodicalId":20152,"journal":{"name":"Physica A: Statistical Mechanics and its Applications","volume":"664 ","pages":"Article 130485"},"PeriodicalIF":2.8,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143529413","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}
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