Pub Date : 2024-06-03DOI: 10.3389/fphy.2024.1408078
Pavel Dvořák, Martina Mrkvičková, Jan Kratzer
The problems of laser-induced fluorescence (LIF) measurements in a partially saturated regime with spatially dependent laser intensity in the sample (caused by absorption) are analyzed. The obtained equations are tested by means of LIF of free tellurium atoms in a plasma of an atmospheric pressure dielectric barrier discharge (DBD) by comparing fluorescence and absorption measurements. The results show a high reliability of LIF measurements.
{"title":"Frontiers | LIF measurement in a partially saturated and partially absorbed regime","authors":"Pavel Dvořák, Martina Mrkvičková, Jan Kratzer","doi":"10.3389/fphy.2024.1408078","DOIUrl":"https://doi.org/10.3389/fphy.2024.1408078","url":null,"abstract":"The problems of laser-induced fluorescence (LIF) measurements in a partially saturated regime with spatially dependent laser intensity in the sample (caused by absorption) are analyzed. The obtained equations are tested by means of LIF of free tellurium atoms in a plasma of an atmospheric pressure dielectric barrier discharge (DBD) by comparing fluorescence and absorption measurements. The results show a high reliability of LIF measurements.","PeriodicalId":12507,"journal":{"name":"Frontiers in Physics","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141569500","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 : 2024-05-31DOI: 10.3389/fphy.2024.1402002
Huibo Liu, Yu Yu, Kai Li, Hengzhe Yu, Di Wu, Yulei Wang, Zhiwei Lu
Stimulated Brillouin scattering (SBS) is a significant nonlinear optical phenomenon utilized across various fields. Its applications span optical sensing, microwave photonics, and all-optical signal processing. In the current information-driven era, the laser industry is imposing increasingly stringent demands on laser technologies, thus propelling integrable on-chip SBS devices into a pivotal research trajectory. Simultaneously, the quest for materials manifesting heightened SBS effects has emerged as a primary focal point in optical fiber transmission endeavors. Lithium niobate (LN) stands out as a promising nonlinear optical material endowed with numerous exemplary attributes. These encompass a high refractive index, fostering potent photon-phonon interactions, low loss characteristics, and high integration potential. Consequently, employing LN as a material for Brillouin lasers promises to enhance certain aspects of laser performance and enable more comprehensive research into Brillouin lasers. In this paper, a micro-ring waveguide structure with LN as the main material is constructed, and the forward gain of stimulated Brillouin scattering, the distribution of electric field in multiple modes and the maximum tunable range are further analyzed. The simulation results exhibit that the tunable forward SBS effect can be achieved in the LN optical waveguides, the maximum forward Brillouin gain can reach 1.34W−1m−1. Additionally, the tunable phonon frequency can range from 1 GHz to 31 GHz, effectively doubling that of silicon ring waveguides and thus extending the range of phonon tunability. Therefore, the LN micro-ring waveguide structure provides a new reference direction for the construction of a new tunable laser and a new idea for the generation of lasers to find a Brillouin medium with high SBS effect.
受激布里渊散射（SBS）是一种重要的非线性光学现象，广泛应用于各个领域。其应用领域包括光学传感、微波光子学和全光学信号处理。在当今信息驱动的时代，激光产业对激光技术提出了越来越严格的要求，从而将可集成的片上 SBS 器件推向了关键的研究轨道。与此同时，在光纤传输领域，对具有更强 SBS 效应的材料的探索也成为一个主要焦点。铌酸锂（LN）是一种前景广阔的非线性光学材料，具有众多典范特性。这些特性包括高折射率、促进有效的光子-声子相互作用、低损耗特性和高集成度潜力。因此，将 LN 用作布里渊激光器的材料有望提高激光器某些方面的性能，并促进对布里渊激光器进行更全面的研究。本文构建了以 LN 为主材料的微环波导结构，并进一步分析了受激布里渊散射的正向增益、多模电场分布和最大可调谐范围。仿真结果表明，在 LN 光波导中可以实现可调谐的正向 SBS 效应，最大正向布里渊增益可达 1.34W-1 m-1。此外，可调谐声子频率范围从 1 GHz 到 31 GHz，实际上是硅环波导的两倍，从而扩大了声子可调谐范围。因此，LN 微环波导结构为构建新型可调谐激光器提供了新的参考方向，也为寻找具有高 SBS 效应的布里渊介质的激光器生成提供了新思路。
{"title":"High-gain lithium niobate brillouin laser with tunable phonon frequency of 1∼31 GHz","authors":"Huibo Liu, Yu Yu, Kai Li, Hengzhe Yu, Di Wu, Yulei Wang, Zhiwei Lu","doi":"10.3389/fphy.2024.1402002","DOIUrl":"https://doi.org/10.3389/fphy.2024.1402002","url":null,"abstract":"Stimulated Brillouin scattering (SBS) is a significant nonlinear optical phenomenon utilized across various fields. Its applications span optical sensing, microwave photonics, and all-optical signal processing. In the current information-driven era, the laser industry is imposing increasingly stringent demands on laser technologies, thus propelling integrable on-chip SBS devices into a pivotal research trajectory. Simultaneously, the quest for materials manifesting heightened SBS effects has emerged as a primary focal point in optical fiber transmission endeavors. Lithium niobate (LN) stands out as a promising nonlinear optical material endowed with numerous exemplary attributes. These encompass a high refractive index, fostering potent photon-phonon interactions, low loss characteristics, and high integration potential. Consequently, employing LN as a material for Brillouin lasers promises to enhance certain aspects of laser performance and enable more comprehensive research into Brillouin lasers. In this paper, a micro-ring waveguide structure with LN as the main material is constructed, and the forward gain of stimulated Brillouin scattering, the distribution of electric field in multiple modes and the maximum tunable range are further analyzed. The simulation results exhibit that the tunable forward SBS effect can be achieved in the LN optical waveguides, the maximum forward Brillouin gain can reach <jats:inline-formula><mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"><mml:mrow><mml:mn>1.34</mml:mn><mml:msup><mml:mi>W</mml:mi><mml:mrow><mml:mo>−</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msup><mml:msup><mml:mrow><mml:mtext> </mml:mtext><mml:mi>m</mml:mi></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math></jats:inline-formula>. Additionally, the tunable phonon frequency can range from 1 GHz to 31 GHz, effectively doubling that of silicon ring waveguides and thus extending the range of phonon tunability. Therefore, the LN micro-ring waveguide structure provides a new reference direction for the construction of a new tunable laser and a new idea for the generation of lasers to find a Brillouin medium with high SBS effect.","PeriodicalId":12507,"journal":{"name":"Frontiers in Physics","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141197708","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 : 2024-05-31DOI: 10.3389/fphy.2024.1411559
Shuai Zhang, Minghong Xie
The semantic segmentation of RGB-D images involves understanding objects appearances and spatial relationships within a scene, which necessitates careful consideration of multiple factors. In indoor scenes, the presence of diverse and disorderly objects, coupled with illumination variations and the influence of adjacent objects, can easily result in misclassifications of pixels, consequently affecting the outcome of semantic segmentation. We propose a Multi-modal Interaction and Pooling Attention Network (MIPANet) in response to these challenges. This network is designed to exploit the interactive synergy between RGB and depth modalities, aiming to enhance the utilization of complementary information and improve segmentation accuracy. Specifically, we incorporate a Multi-modal Interaction Module (MIM) into the deepest layers of the network. This module is engineered to facilitate the fusion of RGB and depth information, allowing for mutual enhancement and correction. Moreover, we introduce a Pooling Attention Module (PAM) at various stages of the encoder to enhance the features extracted by the network. The outputs of the PAMs at different stages are selectively integrated into the decoder through a refinement module to improve semantic segmentation performance. Experimental results demonstrate that MIPANet outperforms existing methods on two indoor scene datasets, NYU-Depth V2 and SUN-RGBD, by optimizing the insufficient information interaction between different modalities in RGB-D semantic segmentation. The source codes are available at https://github.com/2295104718/MIPANet.
{"title":"MIPANet: optimizing RGB-D semantic segmentation through multi-modal interaction and pooling attention","authors":"Shuai Zhang, Minghong Xie","doi":"10.3389/fphy.2024.1411559","DOIUrl":"https://doi.org/10.3389/fphy.2024.1411559","url":null,"abstract":"The semantic segmentation of RGB-D images involves understanding objects appearances and spatial relationships within a scene, which necessitates careful consideration of multiple factors. In indoor scenes, the presence of diverse and disorderly objects, coupled with illumination variations and the influence of adjacent objects, can easily result in misclassifications of pixels, consequently affecting the outcome of semantic segmentation. We propose a Multi-modal Interaction and Pooling Attention Network (MIPANet) in response to these challenges. This network is designed to exploit the interactive synergy between RGB and depth modalities, aiming to enhance the utilization of complementary information and improve segmentation accuracy. Specifically, we incorporate a Multi-modal Interaction Module (MIM) into the deepest layers of the network. This module is engineered to facilitate the fusion of RGB and depth information, allowing for mutual enhancement and correction. Moreover, we introduce a Pooling Attention Module (PAM) at various stages of the encoder to enhance the features extracted by the network. The outputs of the PAMs at different stages are selectively integrated into the decoder through a refinement module to improve semantic segmentation performance. Experimental results demonstrate that MIPANet outperforms existing methods on two indoor scene datasets, NYU-Depth V2 and SUN-RGBD, by optimizing the insufficient information interaction between different modalities in RGB-D semantic segmentation. The source codes are available at <jats:ext-link>https://github.com/2295104718/MIPANet</jats:ext-link>.","PeriodicalId":12507,"journal":{"name":"Frontiers in Physics","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141197709","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 : 2024-05-30DOI: 10.3389/fphy.2024.1370841
Hui Li, Siwen Cui, Yi Huang, Yongsheng Zhao, Pinwen Zhu, Shuailing Ma
The temperature-dependent magnetic susceptibility combined with first-principle calculations was conducted to unravel the magnetic structure and the magnetic interaction of the laminar structure of manganese diboride (MnB2). MnB2 showed weak ferromagnetic, antiferromagnetic, and paramagnetic behavior with increased temperature. Its weak ferromagnetic property below 135.6 K Curie temperature (TC) originated from the spin canting antiferromagnetic magnetic structure. The exotic kink of temperature-dependent magnetic susceptibility at 330 K Néel temperature (TN) correlated with the transition from antiferromagnetic to paramagnetic structure. First-principle calculation show that the antiferromagnetic ordering show lower energy, and suggest a canting anti-ferromagnetic ordering for its ferromagnetic behavior. The peculiar magnetic behavior of MnB2 may be due to the insertion of the honeycomb boron layers into the host matrix of manganese atoms. The honeycomb boron layers played a key role in the exchange between two manganese layers. This study resolved the longstanding puzzle of the magnetic structure of MnB2 and provided a typical laminar magnetic structure prototype.
研究人员结合第一原理计算，研究了随温度变化的磁感应强度，从而揭示了二硼化锰（MnB2）层状结构的磁结构和磁相互作用。随着温度的升高，MnB2 表现出弱铁磁性、反铁磁性和顺磁性。其在 135.6 K 居里温度（TC）以下的弱铁磁特性源于自旋悬臂反铁磁磁性结构。在 330 K 奈尔温度（TN）时，随温度变化的磁感应强度出现奇异的扭结，这与反铁磁结构向顺磁结构的转变有关。第一原理计算表明，反铁磁排序显示出较低的能量，并建议其铁磁行为采用悬臂反铁磁排序。MnB2 的特殊磁性行为可能是由于蜂窝硼层插入到锰原子的主基体中。蜂窝硼层在两个锰层之间的交换中起到了关键作用。这项研究解决了 MnB2 磁性结构的长期难题，并提供了典型的层状磁性结构原型。
{"title":"Investigating the exotic magnetic properties in manganese diboride, a borophene intercalation compound","authors":"Hui Li, Siwen Cui, Yi Huang, Yongsheng Zhao, Pinwen Zhu, Shuailing Ma","doi":"10.3389/fphy.2024.1370841","DOIUrl":"https://doi.org/10.3389/fphy.2024.1370841","url":null,"abstract":"The temperature-dependent magnetic susceptibility combined with first-principle calculations was conducted to unravel the magnetic structure and the magnetic interaction of the laminar structure of manganese diboride (MnB<jats:sub>2</jats:sub>). MnB<jats:sub>2</jats:sub> showed weak ferromagnetic, antiferromagnetic, and paramagnetic behavior with increased temperature. Its weak ferromagnetic property below 135.6 K Curie temperature (T<jats:sub>C</jats:sub>) originated from the spin canting antiferromagnetic magnetic structure. The exotic kink of temperature-dependent magnetic susceptibility at 330 K Néel temperature (T<jats:sub>N</jats:sub>) correlated with the transition from antiferromagnetic to paramagnetic structure. First-principle calculation show that the antiferromagnetic ordering show lower energy, and suggest a canting anti-ferromagnetic ordering for its ferromagnetic behavior. The peculiar magnetic behavior of MnB<jats:sub>2</jats:sub> may be due to the insertion of the honeycomb boron layers into the host matrix of manganese atoms. The honeycomb boron layers played a key role in the exchange between two manganese layers. This study resolved the longstanding puzzle of the magnetic structure of MnB<jats:sub>2</jats:sub> and provided a typical laminar magnetic structure prototype.","PeriodicalId":12507,"journal":{"name":"Frontiers in Physics","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141197659","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 : 2024-05-30DOI: 10.3389/fphy.2024.1399287
Brendan Shanahan
A review of recent advances in simulations of turbulent filaments with relevance to stellarators is presented. Progress in performing global edge turbulence simulations is discussed as well as results from seeded filament simulations with applications to the unique environment of a stellarator island divertor–including abrupt changes in connection length and highly-nonuniform curvature drive. It is determined that the motion of filaments generally follows the average curvature, but strong nonuniform perturbations can shear a filament and reduce the overall transport. The coherence of filament transport is also determined to be influenced by the collisionality and electron plasma beta. By simplifying the simulation geometries, large parameter scans can be performed which accurately reflect the macroscopic transport of filaments observed in Wendelstein 7-X. Comparisons to experiments are discussed, and a the develeopment of a synthetic diagnostic has been able to inform experimental measurements by quantifying potential sources of error in filament propagation measurements. A discussion of the necessary extension to more complex multifluid models, and the scope for near-term filament simulations in stellarators, is provided.
{"title":"Filament simulations for stellarators; a review of recent progress","authors":"Brendan Shanahan","doi":"10.3389/fphy.2024.1399287","DOIUrl":"https://doi.org/10.3389/fphy.2024.1399287","url":null,"abstract":"A review of recent advances in simulations of turbulent filaments with relevance to stellarators is presented. Progress in performing global edge turbulence simulations is discussed as well as results from seeded filament simulations with applications to the unique environment of a stellarator island divertor–including abrupt changes in connection length and highly-nonuniform curvature drive. It is determined that the motion of filaments generally follows the average curvature, but strong nonuniform perturbations can shear a filament and reduce the overall transport. The coherence of filament transport is also determined to be influenced by the collisionality and electron plasma beta. By simplifying the simulation geometries, large parameter scans can be performed which accurately reflect the macroscopic transport of filaments observed in Wendelstein 7-X. Comparisons to experiments are discussed, and a the develeopment of a synthetic diagnostic has been able to inform experimental measurements by quantifying potential sources of error in filament propagation measurements. A discussion of the necessary extension to more complex multifluid models, and the scope for near-term filament simulations in stellarators, is provided.","PeriodicalId":12507,"journal":{"name":"Frontiers in Physics","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141197528","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 : 2024-05-30DOI: 10.3389/fphy.2024.1400919
G. Martini, E. Tentori, M. Mirigliano, D. E. Galli, P. Milani, F. Mambretti
Amid efforts to address energy consumption in modern computing systems, one promising approach takes advantage of random networks of non-linear nanoscale junctions formed by nanoparticles as substrates for neuromorphic computing. These networks exhibit emergent complexity and collective behaviors akin to biological neural networks, characterized by self-organization, redundancy, and non-linearity. Based on this foundation, a generalization of n-inputs devices has been proposed, where the associated weights depend on all the input values. This model, called receptron, has demonstrated its capability to generate Boolean functions as output, representing a significant breakthrough in unconventional computing methods. In this work, we characterize and present two actual implementations of this paradigm. One approach leverages the nanoscale properties of cluster-assembled Au films, while the other utilizes the recently introduced Stochastic Resistor Network (SRN) model. We first provide a concise overview of the electrical properties of these systems, emphasizing the insights gained from the SRN regarding the physical processes within real nanostructured gold films at a coarse-grained scale. Furthermore, we present evidence indicating the minimum complexity level required by the SRN model to achieve a stochastic dynamics adequate to effectively model a novel component for logic systems. To support our argument that these systems are preferable to conventional random search algorithms, we discuss quantitative criteria based on Information-theoretic tools. This suggests a practical means to steer the stochastic dynamics of the system in a controlled way, thus focusing its random exploration where it is most useful.
{"title":"Efficiency and controllability of stochastic boolean function generation by a random network of non-linear nanoparticle junctions","authors":"G. Martini, E. Tentori, M. Mirigliano, D. E. Galli, P. Milani, F. Mambretti","doi":"10.3389/fphy.2024.1400919","DOIUrl":"https://doi.org/10.3389/fphy.2024.1400919","url":null,"abstract":"Amid efforts to address energy consumption in modern computing systems, one promising approach takes advantage of random networks of non-linear nanoscale junctions formed by nanoparticles as substrates for neuromorphic computing. These networks exhibit emergent complexity and collective behaviors akin to biological neural networks, characterized by self-organization, redundancy, and non-linearity. Based on this foundation, a generalization of <jats:italic>n</jats:italic>-inputs devices has been proposed, where the associated weights depend on all the input values. This model, called <jats:italic>receptron</jats:italic>, has demonstrated its capability to generate Boolean functions as output, representing a significant breakthrough in unconventional computing methods. In this work, we characterize and present two actual implementations of this paradigm. One approach leverages the nanoscale properties of cluster-assembled Au films, while the other utilizes the recently introduced Stochastic Resistor Network (SRN) model. We first provide a concise overview of the electrical properties of these systems, emphasizing the insights gained from the SRN regarding the physical processes within real nanostructured gold films at a coarse-grained scale. Furthermore, we present evidence indicating the minimum complexity level required by the SRN model to achieve a stochastic dynamics adequate to effectively model a novel component for logic systems. To support our argument that these systems are preferable to conventional random search algorithms, we discuss quantitative criteria based on Information-theoretic tools. This suggests a practical means to steer the stochastic dynamics of the system in a controlled way, thus focusing its random exploration where it is most useful.","PeriodicalId":12507,"journal":{"name":"Frontiers in Physics","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141197529","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 : 2024-05-29DOI: 10.3389/fphy.2024.1410472
Xinyi Wang, Yuexia Zhang, Siyu Zhang
By caching popular content on edge servers closer to users to respond to users’ content requests in 6G networks, the transmission load of backhaul links can be reduced. However, the time-varying characteristics of content prevalence leads to the issue that the cache content may not match the user’s needs, resulting in a decrease in cache success ratio. To solve these issues, we proposed a cache distribution strategy based on epidemic dynamics (CDSED) for 6G edge network. First, a 6G edge caching content model (6G ECCM) is constructed to establish the process of cache content propagation among users as an infectious disease propagation process, analyze the distribution of users’ interest in cache content and obtain the cache content state probability prediction equation, and use the cache content state probability prediction equation to predict the cache content prevalence. Second, based on the predicted prevalence results, a prevalence predictive genetic-annealing cache content algorithm (PGAC) is proposed with the optimization objective of maximizing the cache success ratio. The algorithm designs the selection function of the traditional genetic algorithm as a simulated annealing selection function based on the cache content success ratio, which avoids the defect of the genetic algorithm that converges to the locally optimum cache strategy too early and enhances the cache success ratio. Finally, the optimum cache content decision is solved by iterative alternation. Simulation results demonstrate that CDSED strategy can enhance cache success ratio than the LRU strategy, the LFU strategy, and the MPC strategy.
{"title":"Frontiers | Epidemic dynamics edge caching strategy for 6G networks","authors":"Xinyi Wang, Yuexia Zhang, Siyu Zhang","doi":"10.3389/fphy.2024.1410472","DOIUrl":"https://doi.org/10.3389/fphy.2024.1410472","url":null,"abstract":"By caching popular content on edge servers closer to users to respond to users’ content requests in 6G networks, the transmission load of backhaul links can be reduced. However, the time-varying characteristics of content prevalence leads to the issue that the cache content may not match the user’s needs, resulting in a decrease in cache success ratio. To solve these issues, we proposed a cache distribution strategy based on epidemic dynamics (CDSED) for 6G edge network. First, a 6G edge caching content model (6G ECCM) is constructed to establish the process of cache content propagation among users as an infectious disease propagation process, analyze the distribution of users’ interest in cache content and obtain the cache content state probability prediction equation, and use the cache content state probability prediction equation to predict the cache content prevalence. Second, based on the predicted prevalence results, a prevalence predictive genetic-annealing cache content algorithm (PGAC) is proposed with the optimization objective of maximizing the cache success ratio. The algorithm designs the selection function of the traditional genetic algorithm as a simulated annealing selection function based on the cache content success ratio, which avoids the defect of the genetic algorithm that converges to the locally optimum cache strategy too early and enhances the cache success ratio. Finally, the optimum cache content decision is solved by iterative alternation. Simulation results demonstrate that CDSED strategy can enhance cache success ratio than the LRU strategy, the LFU strategy, and the MPC strategy.","PeriodicalId":12507,"journal":{"name":"Frontiers in Physics","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141511146","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}
Introduction: Rydberg atoms are ideal for measuring electric fields due to their unique physical properties. However, low-frequency electric fields below MHz can be challenging due to the accumulation of ionized free electrons on the atomic vapor cell’s surface, acting as a shield.Method: This paper proposes a Cavity-enhanced three-photon system (CETPS) measurement scheme, which uses a long-wavelength laser to excite the Rydberg state, reducing atomic ionization and enhancing detection spectrum resolution. A theoretical model is proposed to explain the quantum coherence effect of the light field, measured electric field, and the atomic system.Result: The results show that the proposed scheme significantly increases the electromagnetically induced transparency (EIT) spectral peak and narrows the spectral width, resulting in the maximum slope increasing by more than an order of magnitude.Discussion: The paper also discusses the impact of the Rabi frequency of the two laser fields and the coupling coefficient of the optical cavity on the transmission spectrum amplitude and linewidth, along with the optimal configuration of these parameters in the CEPTS scheme.
{"title":"Frontiers | Low-frequency weak electric field measurement based on Rydberg atoms using cavity-enhanced three photon system","authors":"Dongping Xiao, Zhuxin Shi, Lin Chen, Sheng Yan, Lanxin Xu, Huaiqing Zhang","doi":"10.3389/fphy.2024.1405149","DOIUrl":"https://doi.org/10.3389/fphy.2024.1405149","url":null,"abstract":"Introduction: Rydberg atoms are ideal for measuring electric fields due to their unique physical properties. However, low-frequency electric fields below MHz can be challenging due to the accumulation of ionized free electrons on the atomic vapor cell’s surface, acting as a shield.Method: This paper proposes a Cavity-enhanced three-photon system (CETPS) measurement scheme, which uses a long-wavelength laser to excite the Rydberg state, reducing atomic ionization and enhancing detection spectrum resolution. A theoretical model is proposed to explain the quantum coherence effect of the light field, measured electric field, and the atomic system.Result: The results show that the proposed scheme significantly increases the electromagnetically induced transparency (EIT) spectral peak and narrows the spectral width, resulting in the maximum slope increasing by more than an order of magnitude.Discussion: The paper also discusses the impact of the Rabi frequency of the two laser fields and the coupling coefficient of the optical cavity on the transmission spectrum amplitude and linewidth, along with the optimal configuration of these parameters in the CEPTS scheme.","PeriodicalId":12507,"journal":{"name":"Frontiers in Physics","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141530141","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 : 2024-05-28DOI: 10.3389/fphy.2024.1409427
Fang Wang, Kaixuan Su, Bo Liang, Jian Yao, Wei Bai
In the railway system environment, the interconnection of a vast array of intelligent sensing devices has brought about revolutionary changes in the management and monitoring of railway transportation. However, this also poses challenges to the communication service quality within the railway Internet of Things (IoT). Through collective intelligence and collaboration, the nodes within the railway IoT can not only share data and information but also work synergistically to enhance the overall intelligence level and improve decision-making quality of the network. Therefore, this paper proposes a reconnection mechanism based on the computation of node game-theoretic benefits and optimizes this process with the concept of swarm intelligence collaboration. Initially, the game-theoretic benefit values of the nodes in the railway IoT network are calculated. Subsequently, based on the weight priority of the edges, the two edges with the larger weights are selected, and connections are established between nodes with similar game-theoretic benefit values to enhance the network’s robustness. This approach enables rapid networking and efficient communication transmission within the railway IoT, providing robust assurance for the safe and stable operation of the railway.
{"title":"Research on multi-layer network topology optimization strategy for railway internet of things based on game theory benefits","authors":"Fang Wang, Kaixuan Su, Bo Liang, Jian Yao, Wei Bai","doi":"10.3389/fphy.2024.1409427","DOIUrl":"https://doi.org/10.3389/fphy.2024.1409427","url":null,"abstract":"In the railway system environment, the interconnection of a vast array of intelligent sensing devices has brought about revolutionary changes in the management and monitoring of railway transportation. However, this also poses challenges to the communication service quality within the railway Internet of Things (IoT). Through collective intelligence and collaboration, the nodes within the railway IoT can not only share data and information but also work synergistically to enhance the overall intelligence level and improve decision-making quality of the network. Therefore, this paper proposes a reconnection mechanism based on the computation of node game-theoretic benefits and optimizes this process with the concept of swarm intelligence collaboration. Initially, the game-theoretic benefit values of the nodes in the railway IoT network are calculated. Subsequently, based on the weight priority of the edges, the two edges with the larger weights are selected, and connections are established between nodes with similar game-theoretic benefit values to enhance the network’s robustness. This approach enables rapid networking and efficient communication transmission within the railway IoT, providing robust assurance for the safe and stable operation of the railway.","PeriodicalId":12507,"journal":{"name":"Frontiers in Physics","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141168849","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 : 2024-05-28DOI: 10.3389/fphy.2024.1428875
Yanming Xu, Sen Yang
For the purpose of modeling the acoustic fluid-structure interaction using direct differentiation method and conducting a structural-acoustic sensitivity analysis, a coupling approach based on the finite element method and the fast multipole boundary element method is suggested. Non-uniform rational B-splines isogeometric analysis bypasses the difficult volume parameterization procedure in the isogeometric finite element method and the time-consuming meshing process in classical finite element/boundary element method, allowing numerical analysis on computer-aided design models to be completed directly. The finite element/fast multipole boundary element method based on non-uniform rational B-splines isogeometric analysis enables the numerical prediction of the effects of arbitrarily formed vibrating structures on the sound field. Several numerical examples are shown to demonstrate the usefulness and efficiency of the proposed method.
{"title":"Frontiers | Sensitivity analysis of non-uniform rational B-splines–based finite element/boundary element coupling in structural-acoustic design","authors":"Yanming Xu, Sen Yang","doi":"10.3389/fphy.2024.1428875","DOIUrl":"https://doi.org/10.3389/fphy.2024.1428875","url":null,"abstract":"For the purpose of modeling the acoustic fluid-structure interaction using direct differentiation method and conducting a structural-acoustic sensitivity analysis, a coupling approach based on the finite element method and the fast multipole boundary element method is suggested. Non-uniform rational B-splines isogeometric analysis bypasses the difficult volume parameterization procedure in the isogeometric finite element method and the time-consuming meshing process in classical finite element/boundary element method, allowing numerical analysis on computer-aided design models to be completed directly. The finite element/fast multipole boundary element method based on non-uniform rational B-splines isogeometric analysis enables the numerical prediction of the effects of arbitrarily formed vibrating structures on the sound field. Several numerical examples are shown to demonstrate the usefulness and efficiency of the proposed method.","PeriodicalId":12507,"journal":{"name":"Frontiers in Physics","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141511149","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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