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Symmetry, Volume 17, Issue 2 (February 2025) – 152 articles

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18 pages, 3447 KiB  
Article
A Geometric Berry Phase Angle Induced in Im-3m H3S at 200 GPa by Ultra-Fast Laser Pulses
by Genwei Hong, Xinjie Zhou, Huan He, Tianlv Xu, Herbert Früchtl, Tanja van Mourik, Yaxin Zhai, Steven R. Kirk and Samantha Jenkins
Symmetry 2025, 17(2), 299; https://doi.org/10.3390/sym17020299 (registering DOI) - 16 Feb 2025
Abstract
We investigated Im-3m H3S at 200 GPa, a pressure regime where crystalline H3S is widely considered to be a superconductor. Simulated circularly polarized 10 femtosecond (fs) laser pulses were applied and we quantified the effects on the electron dynamics [...] Read more.
We investigated Im-3m H3S at 200 GPa, a pressure regime where crystalline H3S is widely considered to be a superconductor. Simulated circularly polarized 10 femtosecond (fs) laser pulses were applied and we quantified the effects on the electron dynamics both during the application of the ultra-fast laser pulse and 5.0 fs after the pulse was switched off. In addition, the carrier-envelope phase (CEP) angle ϕ, which quantifies the relationship between the time-varying direction of electric (E)-field and the amplitude envelope, is employed to control the time evolution of the wavefunction ψ(r). This is undertaken for the first application of Next Generation Quantum Theory of Atoms in Molecules (NG-QTAIM) to the solid state. Ultra-fast phenomena related to superconductivity are discovered in the form of a geometric Berry phase angle associated with the H--H bonding in addition to very high values of the chirality–helicity function that correspond to values normally found in chiral molecules. Future applications are discussed, including chiral spin selective phenomena in addition to high-temperature superconductivity and organic superconductors where phonons do not play a significant role. Full article
(This article belongs to the Section Chemistry: Symmetry/Asymmetry)
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23 pages, 19012 KiB  
Article
Modeling and Research on Multi-Speed Heterogeneous Crowd Evacuation with Asymmetric Competitiveness
by Yuanchun Ding and Binwen Liu
Symmetry 2025, 17(2), 298; https://doi.org/10.3390/sym17020298 (registering DOI) - 16 Feb 2025
Abstract
In order to investigate the influence of factors such as pheromones and avoidance behavior on the evacuation of heterogeneous crowds, a multi-speed cellular automata evacuation model based on asymmetric competitiveness is proposed for the evacuation of the complex groups in a single-exit room. [...] Read more.
In order to investigate the influence of factors such as pheromones and avoidance behavior on the evacuation of heterogeneous crowds, a multi-speed cellular automata evacuation model based on asymmetric competitiveness is proposed for the evacuation of the complex groups in a single-exit room. By optimizing the crowd density and pedestrian speed equations, multi-speed heterogeneous crowds can be obtained in the model. In order to achieve the description of a multi-dimensional asymmetric competitiveness heterogeneous population, the evacuation competitiveness is considered in the pedestrians with different speed, age, gender, etc., and by considering the avoidance character existing among pedestrians, the avoidance behavior is also discussed in this model. It is well known that the information received by different pedestrians is different. In order to consider the asymmetry of information, the pheromones are introduced into the evacuation model to discuss the effect of information differences on evacuation. The evacuation results show that the asymmetry of information has a facilitating effect on the evacuation speed of pedestrians, and the best evacuation effect is obtained when the radius of the pheromone is about 3 m. Moreover, evacuation time is weakly correlated with pedestrians’ gender but strongly correlated with pedestrians’ age. The avoidance behavior plays a positive role in evacuation, and the evacuation time reaches the minimum value when the avoidance probability is about 0.5. The slope of the reduction in evacuation time is greatest when the avoidance threshold is 0.4 to 0.8. The findings can support evacuation capacity assessment, emergency planning, and decision making. Full article
(This article belongs to the Section Mathematics)
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25 pages, 3988 KiB  
Article
Symmetry-Inspired Prediction of Nitrous Oxide Emissions in Wastewater Treatment Using Deep Learning and Explainable Analysis
by Zhengze Huang, Yuqi Bai and Hengyu Liu
Symmetry 2025, 17(2), 297; https://doi.org/10.3390/sym17020297 (registering DOI) - 16 Feb 2025
Abstract
Nitrous oxide produced during wastewater treatment is a major greenhouse gas, and accurate prediction and control of N2O emissions are crucial for achieving carbon neutrality. In this study, aiming to address the complex issues of N2O emission prediction in [...] Read more.
Nitrous oxide produced during wastewater treatment is a major greenhouse gas, and accurate prediction and control of N2O emissions are crucial for achieving carbon neutrality. In this study, aiming to address the complex issues of N2O emission prediction in wastewater treatment, large-scale multidimensional data from the Altenrhein wastewater treatment plant was used to build a sample database. The role of symmetry in model architecture and data analysis was discussed, and six intelligent prediction models for N2O emissions were proposed based on deep learning technology. The results showed that the PLO-CNN-BiLSTM-Attention model achieved the best performance, with an R2 of 0.99 on the test set. Engineering validation using 48 subsequent datasets confirmed the model’s strong generalization ability and robustness. Feature importance analysis based on SHAP revealed that water temperature was the most critical factor influencing N2O emissions, while dissolved oxygen concentration and inlet flow rate also had impacts but showed a certain symmetrical change between summer and winter. This study provides efficient and reliable technical support for monitoring and predicting N2O emissions in urban wastewater treatment plants and offers a scientific basis for developing strategies to reduce greenhouse gas emissions. Full article
(This article belongs to the Section Computer)
16 pages, 4920 KiB  
Article
Molecular Dynamics Simulations of CeO2 Nano-Fuel: Thermodynamic and Kinetic Properties
by Rui Zhang, Jianbo Zhou, Yingjie Zhao, Zhen He, Wenxiong Xi and Weidong Zhao
Symmetry 2025, 17(2), 296; https://doi.org/10.3390/sym17020296 (registering DOI) - 16 Feb 2025
Abstract
This study explores the thermodynamic and kinetic properties of CeO2 nano-fuels, with a particular focus on the influence of nanoparticle additives on the diffusion and thermal conductivity of C14-based fuel systems. Using molecular dynamics simulations and the COMPASS force field, we model [...] Read more.
This study explores the thermodynamic and kinetic properties of CeO2 nano-fuels, with a particular focus on the influence of nanoparticle additives on the diffusion and thermal conductivity of C14-based fuel systems. Using molecular dynamics simulations and the COMPASS force field, we model the interactions between C14 molecules and CeO2 nanoparticles, varying nanoparticle size and concentration. Our results reveal that the inclusion of CeO2 nanoparticles leads to significant enhancements in both thermal conductivity (increasing by 9.8–23.6%) and diffusion coefficients (increasing by approximately 140%) within the 20 °C to 100 °C temperature range. These improvements are attributed to the interactions between nanoparticles and fuel molecules, which facilitate more efficient energy and mass transport. Notably, nanoparticles with smaller sizes (0.2 nm and 0.5 nm) exhibit more pronounced effects on both the thermodynamic and kinetic properties than larger nanoparticle analogs (20 nm and 50 nm). The study also highlights the temperature-dependent nature of these properties, demonstrating that nanoparticle additives enhance the fuel’s thermal stability and diffusion behavior, particularly at elevated temperatures. This work provides valuable insights into the optimization of nano-fuel systems, with potential applications in enhancing the performance and efficiency of diesel combustion and heat transfer processes. Full article
(This article belongs to the Special Issue Symmetry Studies in Heat and Mass Transfer)
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13 pages, 260 KiB  
Article
Initial Value Problem for Mixed Differential Equations of Variable Order with Finite Delay
by Souad Guedim, Amar Benkerrouche, Kanokwan Sitthithakerngkiet, Mohammed Said Souid and Abdelkader Amara
Symmetry 2025, 17(2), 295; https://doi.org/10.3390/sym17020295 (registering DOI) - 15 Feb 2025
Abstract
This study presents a fresh perspective on the existence, uniqueness, and stability of solutions for initial value problems involving variable-order differential equations with finite delay. Departing from conventional techniques that utilize generalized intervals and piecewise constant functions, we introduce a novel fractional operator [...] Read more.
This study presents a fresh perspective on the existence, uniqueness, and stability of solutions for initial value problems involving variable-order differential equations with finite delay. Departing from conventional techniques that utilize generalized intervals and piecewise constant functions, we introduce a novel fractional operator tailored for this specific problem. Our methodology integrates sophisticated mathematical analysis, including the Schauder fixed-point theorem and Banach’s contraction principle, with an examination of the Ulam–Hyers stability of the problem. The strength of our approach is in its simplicity, requiring fewer restrictive assumptions. We conclude with a practical application to illustrate our findings. These results are valuable for understanding complex dynamical systems with time delays, offering applications in diverse fields such as engineering, economics, and medicine, and enhancing numerical methods for solving delay equations. Full article
(This article belongs to the Section Mathematics)
25 pages, 1084 KiB  
Article
An Efficient Traceable and Revocable Access Control Scheme for Smart Grids
by Ye Lu, Hao Wang and Xiaomei Jin
Symmetry 2025, 17(2), 294; https://doi.org/10.3390/sym17020294 - 14 Feb 2025
Abstract
In smart grids, power monitoring equipment produces large volumes of data that are exchanged between microgrids and the main grid. This data exchange can potentially expose users’ private information, including their living habits and economic status. Therefore, implementing secure and effective data access [...] Read more.
In smart grids, power monitoring equipment produces large volumes of data that are exchanged between microgrids and the main grid. This data exchange can potentially expose users’ private information, including their living habits and economic status. Therefore, implementing secure and effective data access control mechanisms is crucial. Ciphertext-Policy Attribute-Based Encryption (CP-ABE) is a widely used encryption scheme in distributed systems, offering fine-grained access control. However, in CP-ABE systems, malicious users might leak decryption keys to third parties, creating a significant security threat. Thus, there is an urgent need for tracing mechanisms to identify and track these malicious users. Moreover, tracing and user revocation are complementary processes. Although using a binary tree for user revocation is efficient, it limits the number of users. This paper suggests an access control scheme that combines CP-ABE with blockchain to overcome these limitations, leveraging blockchain’s tamper-resistant features. This scheme enables user revocation, tracing, partial policy hiding, and ciphertext searchability, and it has been proven secure. Simulation results show that our approach reduces time overhead by 24% to 68%, compared to other solutions. While some solutions are similar in efficiency to ours, our approach offers more comprehensive functionality and better meets the security requirements of smart grids. Full article
(This article belongs to the Section Computer)
66 pages, 24939 KiB  
Review
Dynamic Point-to-Helical and Point-to-Axial Chirality Transmission and Induction of Optical Activity in Multichromophoric Systems: Basic Principles and Relevant Applications in Chirality Sensing
by Tomasz Mądry, Jadwiga Gajewy and Marcin Kwit
Symmetry 2025, 17(2), 293; https://doi.org/10.3390/sym17020293 - 14 Feb 2025
Abstract
The analysis of natural and artificial chiral compounds is vital wherever the nuances in the three-dimensional structure are decisive for the possibility of their further use, e.g., as pharmaceuticals or catalysts. The qualitative determination of the structure of a chiral entity requires either [...] Read more.
The analysis of natural and artificial chiral compounds is vital wherever the nuances in the three-dimensional structure are decisive for the possibility of their further use, e.g., as pharmaceuticals or catalysts. The qualitative determination of the structure of a chiral entity requires either an anomalous scattering of X-ray radiation or chiroptical techniques, of which electronic circular dichroism (ECD) is one of the most useful. Chiroptical sensing that uses stereodynamic probes remains one of the remedies for the problem of the lack of a suitable chromophore in the molecules of the chiral compound. A covalent or non-covalent binding of an ECD-silent chiral molecule (the inducer) to the UV-active chromophoric system (chiroptical probe) led to obtaining complex ECD active at a given spectral region. The transfer of structural information from a permanently chiral inducer molecule to the structurally labile chromophoric system of the probe results in adjusting the latter’s structure to the chiral environment. This contribution focuses on some fundamental aspects of chirality sensing using conformationally labile probes. It discusses the mechanism of action of arbitrarily chosen stereodynamic chirality sensors, with particular emphasis on probes based on di- and triarylmethyl derivatives and biphenyl and its congeners. Full article
(This article belongs to the Collection Feature Papers in Chemistry)
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18 pages, 320 KiB  
Article
Symmetric Spaces of Qubits and Gaussian Modes
by Antonio de Jesús Castillo Moctezuma, José Luis Lucio and Alan Josué Sierra-Torres
Symmetry 2025, 17(2), 292; https://doi.org/10.3390/sym17020292 - 14 Feb 2025
Abstract
The understanding of the properties of multipartite systems is a long-standing challenge in quantum theory that signals the need for new ideas and alternative frameworks that can shed light on the intricacies of quantum behavior. In this work, we argue that symmetric spaces [...] Read more.
The understanding of the properties of multipartite systems is a long-standing challenge in quantum theory that signals the need for new ideas and alternative frameworks that can shed light on the intricacies of quantum behavior. In this work, we argue that symmetric spaces provide a common language to describe two-qubit and two-mode Gaussian systems. Our approach relies on the use of equivalence classes that are defined by a subgroup of the maximal symmetry group of the system and involves an involution which enables the Cartan decomposition of the group elements. We work out the symmetric spaces of two qubits and two modes to identify classes which include an equal degree of mixing states, product states, and X states, among others. For three qubits and three modes, we point out how the framework can be generalized and report partial results about the physical interpretations of the symmetric spaces. Full article
(This article belongs to the Section Physics)
19 pages, 955 KiB  
Article
Resolving the Open Problem by Proving a Conjecture on the Inverse Mostar Index for c-Cyclic Graphs
by Liju Alex and Kinkar Chandra Das
Symmetry 2025, 17(2), 291; https://doi.org/10.3390/sym17020291 - 14 Feb 2025
Abstract
Inverse topological index problems involve determining whether a graph exists with a given integer as its topological index. One such index, the Mostar indexMo(G), is defined as [...] Read more.
Inverse topological index problems involve determining whether a graph exists with a given integer as its topological index. One such index, the Mostar indexMo(G), is defined as Mo(G)=uvE(G)|nu(e|G)nv(e|G)|, where nu(e|G) and nv(e|G) represent the number of vertices closer to vertex u than v and closer to v than u, respectively, for an edge e=uv. The inverse Mostar index problem has gained significant attention recently. In their work, Alizadeh et al. [Solving the Mostar index inverse problem, J. Math. Chem. 62 (5) (2024) 1079–1093] proposed the following open problem: “Which nonnegative integers can be realized as Mostar indices of c-cyclic graphs, for a given positive integer c?”. Subsequently, one of the present authors [On the inverse Mostar index problem for molecular graphs, Trans. Comb. 14 (1) (2024) 65–77] conjectured that, except for finitely many positive integers, all other positive integers can be realized as the Mostar index of a c-cyclic graph, where c3. In this paper, we address the inverse Mostar index problem for c-cyclic graphs. Specifically, we construct infinitely many families of symmetric c-cyclic structures, thereby demonstrating a solution to the inverse Mostar index problem using an infinite family of such symmetric structures. By providing a comprehensive proof of the conjecture, we fully resolve this longstanding open problem. Full article
(This article belongs to the Special Issue Symmetry and Graph Theory, 2nd Edition)
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20 pages, 37686 KiB  
Article
Multi-Source Training-Free Controllable Style Transfer via Diffusion Models
by Cuihong Yu, Cheng Han and Chao Zhang
Symmetry 2025, 17(2), 290; https://doi.org/10.3390/sym17020290 - 13 Feb 2025
Abstract
Diffusion models, as representative models in the field of artificial intelligence, have made significant progress in text-to-image synthesis. However, studies of style transfer using diffusion models typically require a large amount of text to describe semantic content or specific painting attributes, and the [...] Read more.
Diffusion models, as representative models in the field of artificial intelligence, have made significant progress in text-to-image synthesis. However, studies of style transfer using diffusion models typically require a large amount of text to describe semantic content or specific painting attributes, and the style and layout of semantic content in synthesized images are frequently uncertain. To accomplish high-quality fixed content style transfer, this paper adopts text-free guidance and proposes a multi-source, training-free and controllable style transfer method by using single image or video as content input and single or multiple style images as style guidance. To be specific, the proposed method firstly fuses the inversion noise of a content image with that of a single or multiple style images as the initial noise of stylized image sampling process. Then, the proposed method extracts the self-attention mechanism’s query, key, and value vectors from the DDIM inversion process of content and style images and injects them into the stylized image sampling process to improve the color, texture and semantics of stylized images. By setting the hyperparameters involved in the proposed method, the style transfer effect of symmetric style proportion and asymmetric style distribution can be achieved. By comparing with state-of-the-art baselines, the proposed method demonstrates high fidelity and excellent stylized performance, and can be applied to numerous image or video style transfer tasks. Full article
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22 pages, 7863 KiB  
Article
Enhancement of Thermomechanical Protocol for Automotive Brake Using the Symmetry of the Disc: Numerical Validation and Material Selection
by Mohammed Berrada Gouzi, Ali Hajjia, Ahmed El Khalfi, Bilal Harras, Sorin Vlase and Maria Luminita Scutaru
Symmetry 2025, 17(2), 289; https://doi.org/10.3390/sym17020289 - 13 Feb 2025
Abstract
In the context of the automotive industry, this paper proposes an enhancement of the numerical simulation using FEM and performing material choosing with the Ashby method for automotive brake discs, using the symmetric shape of the disc. Automotive braking involves the dissipation of [...] Read more.
In the context of the automotive industry, this paper proposes an enhancement of the numerical simulation using FEM and performing material choosing with the Ashby method for automotive brake discs, using the symmetric shape of the disc. Automotive braking involves the dissipation of kinetic energy through heat generation due to friction, a physical phenomenon that alters the mechanical properties of brake discs. This prompts automotive development engineers to investigate new materials capable of absorbing heat while maintaining their mechanical properties. A thermomechanical study of a ventilated front brake disc has successfully demonstrated a good performance of cast iron because the equivalent stress is significantly lower than the elastic limit, with a margin of approximately 73 MPa. Compared to validated results extracted from the state of the art, the adopted methodology gives more realistic results with minimum CPU requirements, where the total time of calculation is around 40 min. More than that, the results are suitable to be used for studying durability and other properties like mechanical impact and fatigue. Full article
(This article belongs to the Special Issue Symmetry and Asymmetry in Nonlinear Systems)
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15 pages, 298 KiB  
Article
Symmetry Properties and Their Application to Hilfer Fractional Systems
by Beata Sikora
Symmetry 2025, 17(2), 288; https://doi.org/10.3390/sym17020288 - 13 Feb 2025
Abstract
The paper investigates semilinear Hilfer fractional systems. A symmetric fractional derivative and its properties are discussed. A symmetrized model for these systems is proposed and examined. A bounded nonlinear function f is applied, depending on the time as well as on the state. [...] Read more.
The paper investigates semilinear Hilfer fractional systems. A symmetric fractional derivative and its properties are discussed. A symmetrized model for these systems is proposed and examined. A bounded nonlinear function f is applied, depending on the time as well as on the state. The Laplace transformation is used to derive the solution formula for the systems under consideration. The primary contribution of the paper is the formulation and proof of controllability criteria for symmetrized Hilfer systems. To deepen the understanding of the dynamics of such systems, the concept of reflection symmetries is introduced with a detailed analysis of their essential features, including projection functions and a reflection operator. Furthermore, a decomposition of the symmetric Hilfer fractional derivative is presented, utilizing the projection function and reflection operator. This decomposition not only provides a controllability condition for symmetrized Hilfer systems but also clarifies the relationship between the system’s trajectory across subintervals. Two illustrative examples are presented to demonstrate the computational and practical significance of the theoretical results. Full article
(This article belongs to the Special Issue Symmetry and Asymmetry in Nonlinear Systems)
17 pages, 5463 KiB  
Article
Asymmetric Finite-Range Persistence in Time Series Generated by the Modified Discrete Langevin Model
by Zbigniew Czechowski
Symmetry 2025, 17(2), 287; https://doi.org/10.3390/sym17020287 - 13 Feb 2025
Abstract
The concept of asymmetric persistence in time series was proposed and an appropriate stochastic Langevin-type model was presented. The influence of this particular form of memory on the behavior of the generated time series was examined. It has been shown that asymmetry causes [...] Read more.
The concept of asymmetric persistence in time series was proposed and an appropriate stochastic Langevin-type model was presented. The influence of this particular form of memory on the behavior of the generated time series was examined. It has been shown that asymmetry causes a significant distortion of the effect of drift forces and has a weaker impact on stochastic diffusion forces. Due to this, the current known methods for reconstructing the Langevin-type model fail. The results of this work may help in deriving a new reconstruction method. Full article
(This article belongs to the Section Physics)
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13 pages, 3483 KiB  
Article
Deep Learning-Based Exposure Asymmetry Multispectral Reconstruction from Digital RGB Images
by Jinxing Liang, Xin Hu, Wensen Zhou, Kaida Xiao and Zhaojing Wang
Symmetry 2025, 17(2), 286; https://doi.org/10.3390/sym17020286 - 13 Feb 2025
Abstract
Multispectral reconstruction is an important way to acquire spectral images with a high spatial resolution as snapshots. Current deep learning-based multispectral reconstruction models perform well under symmetric conditions, where the exposure of training and testing images is consistent. However, further research has shown [...] Read more.
Multispectral reconstruction is an important way to acquire spectral images with a high spatial resolution as snapshots. Current deep learning-based multispectral reconstruction models perform well under symmetric conditions, where the exposure of training and testing images is consistent. However, further research has shown that these models are sensitive to exposure changes. When the exposure symmetry is not maintained and testing images are input into the multispectral reconstruction model under different exposure conditions, the reconstructed multispectral images tend to deviate from the real ground truth to varying degrees. This limitation restricts the robustness and applicability of the model in practical scenarios. To address this challenge, we propose an exposure estimation multispectral reconstruction model of EFMST++ with data augmentation and optimized deep learning architecture, where Retinex decomposition and a wavelet transform are introduced into the proposed model. Based on the currently available dataset in this field, a comprehensive comparison is made between the proposed and existing models. The results show that after the current multispectral reconstruction models are retrained using the augmented datasets, the average MRAE and RMSE of the current most advanced model of MST++ are reduced from 0.570 and 0.064 to 0.236 and 0.040, respectively. The proposed method further reduces the average MRAE and RMSE to 0.229 and 0.037, with the average PSNR increasing from 27.94 to 31.43. The proposed model supports the use of multispectral reconstruction in open environments. Full article
(This article belongs to the Section Computer)
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20 pages, 1332 KiB  
Article
Time-Irreversible Quantum-Classical Dynamics of Molecular Models in the Brain
by Alessandro Sergi, Antonino Messina, Rosalba Saija, Gabriella Martino, Maria Teresa Caccamo, Min-Fang Kuo and Michael A. Nitsche
Symmetry 2025, 17(2), 285; https://doi.org/10.3390/sym17020285 - 13 Feb 2025
Abstract
This manuscript aims to illustrate a quantum-classical dissipative theory (suited to be converted to effective algorithms for numerical simulations) within the long-term project of studying molecular processes in the brain. Other approaches, briefly sketched in the text, have advocated the need to deal [...] Read more.
This manuscript aims to illustrate a quantum-classical dissipative theory (suited to be converted to effective algorithms for numerical simulations) within the long-term project of studying molecular processes in the brain. Other approaches, briefly sketched in the text, have advocated the need to deal with both quantum and classical dynamic variables when studying the brain. At variance with these other frameworks, the manuscript’s formalism allows us to explicitly treat the classical dynamical variables. The theory must be dissipative not because of formal requirements but because brain processes appear to be dissipative at the molecular, physiological, and high functional levels. We discuss theoretically that using Brownian dynamics or the Nosè-Hoover-Chain thermostat to perform computer simulations provides an effective way to introduce an arrow of time for open quantum systems in a classical environment. In the future, We plan to study classical models of neurons and astrocytes, as well as their networks, coupled to quantum dynamical variables describing, e.g., nuclear and electron spins, HOMO and LUMO orbitals of phenyl and indole rings, ion channels, and tunneling protons. Full article
(This article belongs to the Section Physics)
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24 pages, 1188 KiB  
Article
A Probabilistic Approach to Overestimation by an Imperfect Inspector Subject to Random Defective Rates
by Kyo-Chan Koo
Symmetry 2025, 17(2), 284; https://doi.org/10.3390/sym17020284 - 12 Feb 2025
Abstract
This study investigates overestimations in defect inspections performed by imperfect inspectors, particularly in scenarios involving random defective rates. Mathematical models are developed under two key assumptions: (1) inspection errors are either constant or uniformly distributed and (2) defective rates follow a random uniform [...] Read more.
This study investigates overestimations in defect inspections performed by imperfect inspectors, particularly in scenarios involving random defective rates. Mathematical models are developed under two key assumptions: (1) inspection errors are either constant or uniformly distributed and (2) defective rates follow a random uniform distribution. Four analytical models are used to evaluate the probability of overestimation (PO) and identify critical defect rate thresholds (CFBs). The findings reveal that the PO approaches 100% as defect rates approach zero, irrespective of inspection error characteristics. Sensitivity analysis demonstrates model robustness under varying error distributions and parameter changes. Addressing practical concerns, this research highlights the need to revise inspection schemes to mitigate biases, especially in industries with stringent quality control standards, such as electronics and pharmaceuticals. Recommendations include integrating probabilistic error models and adopting dynamic calibration systems to improve inspection accuracy. By providing a theoretical foundation for tackling overestimation, this study has significant implications for improving fairness and efficiency in global supply chains. Full article
(This article belongs to the Section Mathematics)
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21 pages, 30798 KiB  
Article
Symmetric Circle Configurations from Regular Skeletal Polyhedra
by Jieying Jin and Egon Schulte
Symmetry 2025, 17(2), 283; https://doi.org/10.3390/sym17020283 - 12 Feb 2025
Abstract
The paper studies finite and infinite periodic point-circle configurations in ordinary Euclidean 3-space associated with regular skeletal polyhedra or related structures. The configurations preserve all the symmetries of the underlying polyhedron and, in most cases, are point-circle transitive. Illustrations of many highly symmetric [...] Read more.
The paper studies finite and infinite periodic point-circle configurations in ordinary Euclidean 3-space associated with regular skeletal polyhedra or related structures. The configurations preserve all the symmetries of the underlying polyhedron and, in most cases, are point-circle transitive. Illustrations of many highly symmetric point-circle configurations are provided. Full article
(This article belongs to the Special Issue Symmetry in Discrete and Combinatorial Geometry)
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32 pages, 23122 KiB  
Article
Mathematical Modeling of Individual Behavior Based on Viewpoint Dynamics: Analyzing Group Cohesion Effects Induced by Individual Potential Power Differences
by Chenyang Li, Yonghui Yang and Xue-Bo Chen
Symmetry 2025, 17(2), 282; https://doi.org/10.3390/sym17020282 - 12 Feb 2025
Abstract
The group cohesion effect refers to individuals’ identification with the group’s viewpoint, resulting from behavioral and cognitive changes during interactions, and is crucial for group development. However, individual differences in intrinsic characteristics lead to varied group behaviors and cohesion. This paper uses a [...] Read more.
The group cohesion effect refers to individuals’ identification with the group’s viewpoint, resulting from behavioral and cognitive changes during interactions, and is crucial for group development. However, individual differences in intrinsic characteristics lead to varied group behaviors and cohesion. This paper uses a mathematical model based on viewpoint dynamics to explore how these differences shape group cohesion. The primary consideration is the potential power inherent in individual characteristics, which can be understood as symmetry-breaking concepts. In the model, individuals are classified into two types, each supporting one of two viewpoints. The potential power reflects the individuals’ degree of firmness regarding their viewpoint and their perceptual range. Differences in the potential power, both within and between types, drive shifts in viewpoints and behaviors, generating diverse cohesion effects. Additionally, the model also incorporates the influence of group size and external factors, such as individuals with no viewpoints and those holding public opinion viewpoints. The results indicate that group size has no significant effect on group cohesion, while individuals with no viewpoints contribute to stabilizing it, whereas individuals with public opinions weaken it. These findings highlight the complex relationship between individual differences in potential power and group cohesion, suggesting that symmetry-breaking dynamics can effectively explain group cohesion effects. Full article
(This article belongs to the Section Mathematics)
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20 pages, 1044 KiB  
Article
Reliable Transmission of Energy Harvesting Full-Duplex Relay Systems with Short-Packet Communications
by Chenxi Yang, Mingkang Yu, Jinshu Huang, Dechuan Chen, Jin Li and Pei Jiang
Symmetry 2025, 17(2), 281; https://doi.org/10.3390/sym17020281 - 12 Feb 2025
Abstract
Energy harvesting (EH) from radio frequency (RF) signals provides a promising approach for supplying sustainable and convenient energy to low-power Internet of Things (IoT) devices. In this work, we investigate short-packet communications in a full-duplex (FD) relay system, where RF signals from a [...] Read more.
Energy harvesting (EH) from radio frequency (RF) signals provides a promising approach for supplying sustainable and convenient energy to low-power Internet of Things (IoT) devices. In this work, we investigate short-packet communications in a full-duplex (FD) relay system, where RF signals from a source are utilized to power an energy-constrained relay through the time switching protocol. Specifically, hardware impairments in each node and residual self-interference caused by FD are jointly considered. To ensure reliable transmission, two antennas are symmetrically arranged according to the position of the relay station, both of which are used for energy harvesting. Furthermore, we explored two practical schemes based on symmetric channel correlation, i.e., an independent channel for energy harvesting and an identical channel for energy harvesting. For both scenarios, we derive closed-form approximations for the overall average block error rate (BLER) and effective throughput. The validity of our analysis is confirmed through computer simulations, demonstrating that the proposed scheme enhances the reliability and throughput of the system compared with the existing scheme in the literature at low transmission rates and transmit signal-to-noise-ratios (SNRs). Full article
(This article belongs to the Special Issue Symmetry/Asymmetry in Future Wireless Networks)
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19 pages, 906 KiB  
Article
HICA: A Hybrid Scientific Workflow Scheduling Algorithm for Symmetric Homogeneous Resource Cloud Environments
by Liang Hu, Xianwei Wu and Xilong Che
Symmetry 2025, 17(2), 280; https://doi.org/10.3390/sym17020280 - 12 Feb 2025
Abstract
With the increasing volume of scientific computation data and the advancement of computer performance, scientific computation is becoming more dependent on the powerful computing capabilities of cloud computing. On cloud platforms, tasks in scientific workflows are assigned to computational resources and executed according [...] Read more.
With the increasing volume of scientific computation data and the advancement of computer performance, scientific computation is becoming more dependent on the powerful computing capabilities of cloud computing. On cloud platforms, tasks in scientific workflows are assigned to computational resources and executed according to specific strategies. Therefore, workflow scheduling has become a key factor affecting efficiency. This paper proposes a hybrid scientific workflow scheduling algorithm, HICA, to address the scheduling problem of scientific workflows in symmetric homogeneous cloud environments with optimization goals of makespan and cost. HICA combines the Imperialist Competitive Algorithm (ICA) with the HEFT algorithm, integrating HEFT into the initial population of the ICA to accelerate the convergence of the ICA. Experimental results show that the proposed hybrid approach outperforms other algorithms in real-world workflow applications. Specifically, when the workflow scale is 100, the average improvements in makespan and cost are 133.89 and 273.33, respectively; when the workflow scale is 1000, the improvements are 371.62 and 9178.98. The scheduling results for the Earth System Model parameter tuning workflow show that compared to the scenario without using a scheduling algorithm, the makespan and cost were improved by 13% and 21%, respectively. Full article
(This article belongs to the Section Computer)
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14 pages, 276 KiB  
Article
Eigenvalues for the Generalized Laplace Operator of Slant Submanifolds in the Sasakian Space Forms Admitting Semi-Symmetric Metric Connection
by Ibrahim Al-Dayel, Meraj Ali Khan and Sudhakar Kumar Chaubey
Symmetry 2025, 17(2), 279; https://doi.org/10.3390/sym17020279 - 11 Feb 2025
Abstract
This study is focused on pioneering new upper bounds on mean curvature and constant sectional curvature relative to the first positive eigenvalue of the generalized Laplacian operator in the differentiable manifolds with a semi-symmetric metric connection. Multiple approaches are being explored to determine [...] Read more.
This study is focused on pioneering new upper bounds on mean curvature and constant sectional curvature relative to the first positive eigenvalue of the generalized Laplacian operator in the differentiable manifolds with a semi-symmetric metric connection. Multiple approaches are being explored to determine the principal eigenvalue for the generalized-Laplacian operator in closed oriented-slant submanifolds within a Sasakian space form (ssf) with a semi-symmetric metric (ssm) connection. By utilizing our findings on the Laplacian, we extend several Reilly-type inequalities to the generalized Laplacian on slant submanifolds within a unit sphere with a semi-symmetric metric (ssm) connection. The research is concluded with a detailed examination of specific scenarios. Full article
23 pages, 3143 KiB  
Article
A Flexible Unit Distribution Based on a Half-Logistic Map with Applications in Stochastic Data Modeling
by Vladica S. Stojanović, Hassan S. Bakouch, Gadir Alomair, Amira F. Daghestani and Željko Grujčić
Symmetry 2025, 17(2), 278; https://doi.org/10.3390/sym17020278 - 11 Feb 2025
Abstract
In this manuscript, a new two-parameter stochastic distribution is proposed and obtained by a continuous half-logistic transformation of the quasi-Lindley (QL) distribution to the unit interval. The resulting distribution, named the quasi-Lindley half-logistic unit (QHU) distribution, is examined in terms of its key [...] Read more.
In this manuscript, a new two-parameter stochastic distribution is proposed and obtained by a continuous half-logistic transformation of the quasi-Lindley (QL) distribution to the unit interval. The resulting distribution, named the quasi-Lindley half-logistic unit (QHU) distribution, is examined in terms of its key stochastic properties, such as asymmetry conditions, shape and modality, moments, etc. In addition, the stochastic dominance of the proposed distribution with respect to its parameters is considered, and it is shown that the QHU distribution, in contrast to the QL distribution that is always positively asymmetric, can have both asymmetric forms. The parameters of the QHU distribution are estimated by the maximum likelihood (ML) method, and the asymptotic properties of thusly obtained estimators are examined. Finally, an application of the proposed distribution in modeling some real-world phenomena is also presented. Full article
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17 pages, 3674 KiB  
Article
Intelligent Performance Degradation Prediction of Light-Duty Gas Turbine Engine Based on Limited Data
by Chunyan Hu, Keqiang Miao, Mingyang Zhou, Yafeng Shen and Jiaxian Sun
Symmetry 2025, 17(2), 277; https://doi.org/10.3390/sym17020277 - 11 Feb 2025
Abstract
The health monitoring system has been the main technological approach to extending the life of gas turbine engines and reducing maintenance costs resulting from performance degradation caused by asymmetric factors like carbon deposition, damage, or deformation. One of the most critical techniques within [...] Read more.
The health monitoring system has been the main technological approach to extending the life of gas turbine engines and reducing maintenance costs resulting from performance degradation caused by asymmetric factors like carbon deposition, damage, or deformation. One of the most critical techniques within the health monitoring system is performance degradation prediction. At present, most research on degradation prediction is carried out using NASA’s open dataset, C-MAPSS, without considering that monitoring measurements are not always available, as in the ideal dataset. This limitation makes fault diagnosis algorithms and remaining useful life prediction methods difficult to apply to real gas turbine engines. Therefore, to solve the problem of performance degradation prediction in light-duty gas turbine engines, a prediction diagram is proposed based on Long Short-Term Memory (LSTM). Various types of onboard signals are taken into consideration among the experimental data. Only accumulated usage time, total temperature and total pressure before the inlet, low-pressure rotor speed, high-pressure rotor speed, fuel flow rate, exhaust temperature, and thrust are used in the training process, which is indispensable for an aero-engine. A genetic algorithm (GA) is introduced into the training process to optimize the hyperparameters of LSTM. The performance degradation prediction modeled with the GA-LSTM method is validated using experimental data. The maximum prediction error of thrust is 70 daN, and the mean absolute percentage error (MAPE) is less than 0.04. This study provides a practical approach to implementing performance degradation prediction in health monitoring systems to improve gas turbine engine reliability, economy, and environmental performance. Full article
(This article belongs to the Section Engineering and Materials)
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22 pages, 3482 KiB  
Article
A Q-Learning Evolutionary Algorithm for Solving the Distributed Mixed No-Idle Permutation Flowshop Scheduling Problem
by Fangchi Zeng and Junjia Cui
Symmetry 2025, 17(2), 276; https://doi.org/10.3390/sym17020276 - 11 Feb 2025
Abstract
In this paper, a Distributed Mixed No-Idle Permutation Flowshop Scheduling Problem with Sequence-Dependent Setup Times (DMNIPFSP/SDST) is studied. Firstly, a multi-objective optimization model with completion time (makespan), Total Energy Consumption (TEC), and Total Tardiness (TT) as objectives is established. Based on problem characteristics [...] Read more.
In this paper, a Distributed Mixed No-Idle Permutation Flowshop Scheduling Problem with Sequence-Dependent Setup Times (DMNIPFSP/SDST) is studied. Firstly, a multi-objective optimization model with completion time (makespan), Total Energy Consumption (TEC), and Total Tardiness (TT) as objectives is established. Based on problem characteristics and multi-objective characteristics, a Q-Learning Evolutionary Algorithm (QLEA) is proposed. Secondly, in order to improve the quality and diversity of the initial solution, two improved initialization strategies are proposed. Based on the characteristics of the problem solved (In the distributed system, symmetry design is adopted to ensure that the load of each workstation is relatively balanced in different time periods, avoid resource waste or bottleneck, and achieve the goal of no idle.), a novel population updating mechanism is designed to balance the ability of global exploration and local development of the algorithm. At the same time, a variable neighborhood local search based on Q-Learning is used to refine the non-dominated solution, thus guiding the population evolution. Finally, the simulation results show that this method has good performance in solving the multi-objective DMNIPFSP/SDST and can provide good economic benefits for enterprises. Full article
(This article belongs to the Special Issue Meta-Heuristics for Manufacturing Systems Optimization Ⅱ)
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31 pages, 28841 KiB  
Article
Fuzzy-Probabilistic Time Series Forecasting Combining Bayesian Network and Fuzzy Time Series Model
by Bo Wang and Xiaodong Liu
Symmetry 2025, 17(2), 275; https://doi.org/10.3390/sym17020275 - 11 Feb 2025
Abstract
Despite many fuzzy time series forecasting (FTSF) models addressing complex temporal patterns and uncertainties in time series data, two limitations persist: they do not treat fuzzy and crisp time series as a unified whole for analyzing nonlinear relationships between different moments, and they [...] Read more.
Despite many fuzzy time series forecasting (FTSF) models addressing complex temporal patterns and uncertainties in time series data, two limitations persist: they do not treat fuzzy and crisp time series as a unified whole for analyzing nonlinear relationships between different moments, and they fail to effectively capture how uncertainty in temporal patterns affects predictions. In this paper, we propose an FTSF model integrating Bayesian networks to overcome the limitations. Bayesian network (BN) structure learning is employed to extract fuzzy–crisp dependencies between historical fuzzified data and predicted crisp data alongside temporal crisp dependencies within crisp data. Integrating fuzzy logical relationship groups (FLRGs) and the two BNs representing the fuzzy–crisp and crisp relationships identifies temporal patterns efficiently. BN parameter learning models the occurrence uncertainties of dependencies through conditional probability distributions in BNs, while fuzzy empirical conditional probabilities quantify the occurrence uncertainties of the elements in FLRGs. The defuzzification stage infers the crisp predicted value using the fuzzy-empirical-probability weighted FLRGs and the two BN. We validate the forecasting performance of the proposed model on sixteen diverse time series. Experimental results demonstrate the competitive forecasting performance of the proposed model compared to state-of-the-art methods. Full article
(This article belongs to the Section Mathematics)
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9 pages, 4323 KiB  
Article
Simultaneous Generation of Linear- and Circular-Polarization Vortex Based on Symmetrical Metallic Quasi-Metasurface
by Daoheng Zhu, Xiaokun Yang, Lingbo Han and Jian Yan
Symmetry 2025, 17(2), 274; https://doi.org/10.3390/sym17020274 - 10 Feb 2025
Abstract
Through comprehensive research on the working principles of the generalized Snell’s law, this paper presents a quasi-metasurface based on the theory of wavefront difference. The proposed structure successfully demonstrates the vortex manipulation of both linearly polarized waves and circularly polarized waves. The symmetrical [...] Read more.
Through comprehensive research on the working principles of the generalized Snell’s law, this paper presents a quasi-metasurface based on the theory of wavefront difference. The proposed structure successfully demonstrates the vortex manipulation of both linearly polarized waves and circularly polarized waves. The symmetrical metallic column design modulates the phase of one period at 18 GHz with a reflection loss of less than −0.5 dB. By decomposing circularly polarized waves into a set of mutually orthogonal linearly polarized waves with a phase difference of π/2, a simple synthesis method is proposed to convert existing linearly polarized waves into circularly polarized waves, thereby demonstrating vortex wave effects. The quasi-metasurface exhibits excellent performance, and the vortex characteristics of both linearly and circularly polarized waves are verified through simulations. Full article
(This article belongs to the Section Physics)
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112 pages, 965 KiB  
Review
Something Anomalies Can Tell About Standard Model and Gravity
by Loriano Bonora and Stefano Gregorio Giaccari
Symmetry 2025, 17(2), 273; https://doi.org/10.3390/sym17020273 - 10 Feb 2025
Abstract
This is a review/research paper on anomalies applied in a bottom–up approach to standard model and gravity. It is divided into two parts. The first consists of a proper review of anomalies in quantum field theories. Anomalies are analyzed according to three different [...] Read more.
This is a review/research paper on anomalies applied in a bottom–up approach to standard model and gravity. It is divided into two parts. The first consists of a proper review of anomalies in quantum field theories. Anomalies are analyzed according to three different methods: a perturbative one based on a Feynman diagram, a non-perturbative one relying on the Schwinger–DeWitt approach, and, third, one hinging on the Atiyah–Singer family’s index theorem. The three methods are applied both to chiral gauge anomalies and trace anomalies. The fundamental distinction, which our presentation leads to, is between obstructive (O) and non-obstructive (NO) anomalies. The former is tied to the non-existence of fermion propagators, which fatally maim the corresponding theory. In the second part, we apply this analysis to the SM and a variety of its extensions, which are immersed in a gravitational background, and we find that they are all plagued by a residual chiral trace anomaly. To completely eliminate all kinds of dangerous anomalies in SM-like theories, we propose a somewhat unconventional scheme and exemplify it by means of an explicit model. The latter is a left–right symmetric model. We embed it in a Weyl geometry to render it a conformal invariant. We then deal with some of its quantum aspects, particularly its even (NO) trace anomalies and the means to preserve its conformal invariance at the quantum level. We briefly review renormalization and unitarity in the framework of similar models discussed in the existing literature. Finally, we present a possible (conjectural) application of the model to describe the junction between cosmology and quantum field theory. Full article
(This article belongs to the Special Issue Generalized Symmetries and Fractons in Gauge Theories)
39 pages, 337 KiB  
Article
Optimization of Fresh Produce Supply Chain Resilience Capacity: An Extension Strategy Generation Method
by Qianlan Chen, Chaoling Li, Lin Lu, Youan Ke, Kai Kang, Siyi Mao and Zhangzheyi Liao
Symmetry 2025, 17(2), 272; https://doi.org/10.3390/sym17020272 - 10 Feb 2025
Abstract
Fresh produce, as a primary source of nutrition, plays a pivotal role in daily life. However, the unique characteristics of fresh produce—such as perishability, widespread production, short shelf life, long distribution cycles, and high volatility in both supply and demand—render the fresh produce [...] Read more.
Fresh produce, as a primary source of nutrition, plays a pivotal role in daily life. However, the unique characteristics of fresh produce—such as perishability, widespread production, short shelf life, long distribution cycles, and high volatility in both supply and demand—render the fresh produce supply chain particularly vulnerable to disruptions. These vulnerabilities not only impact daily consumption but also pose significant challenges to the operational efficiency of enterprises. Enhancing the fresh produce supply chain resilience is crucial for businesses to effectively mitigate risks, ensure consistent product quality, and maintain overall supply chain stability. Nevertheless, there remains a lack of clear, process-oriented guidance for developing resilience improvement strategies within the fresh agricultural product sector. Specifically, there is insufficient clarity regarding which elements should be prioritized for investment in resilience strategies, how these strategies should be formulated, and the absence of a theoretically sound framework to guide the strategic development of supply chain resilience improvements. To address the lack of scientific, quantitative, efficient, and specific processes for generating supply chain resilience improvement strategies in fresh agricultural product enterprises, this study adopts the framework of extensible primitive theory. Initially, an evaluation index system for the fresh produce supply chain is constructed, and the extendable evaluation method is employed to assess the resilience level of fresh agricultural product enterprises. This approach facilitates the identification of the key challenges that must be addressed to enhance supply chain resilience and helps generate strategies that reconcile previously incompatible issues. Next, the core objectives and conditions underlying the resilience incompatibilities in fresh agricultural product enterprises are quantitatively analyzed. Finally, the expansion transformation of both target and condition primitives is carried out to derive the optimal strategy for improving supply chain resilience. The study uses company M as a case example, where the evaluation results indicate that the company’s supply chain resilience is rated as “good”. However, several issues were identified, including inefficiencies in product supply, limited financing capacity, low enterprise visibility, and inadequate production and processing equipment. Based on these findings, the paper proposes a series of optimization strategies aimed at improving the fresh produce supply chain resilience through extension transformation. Full article
(This article belongs to the Section Mathematics)
16 pages, 279 KiB  
Article
The Neutrosophization of δ-Separation Axioms
by Ahu Açikgöz, Ferhat Esenbel, Abdulhamit Maman and Seher Zorlu
Symmetry 2025, 17(2), 271; https://doi.org/10.3390/sym17020271 - 10 Feb 2025
Abstract
Fuzzy topology has long been celebrated for its ability to address real-world challenges in areas such as information systems and decision making. However, with ongoing technological advancements and the increasing complexity of practical requirements, the focus has gradually shifted toward neutrosophic topology, a [...] Read more.
Fuzzy topology has long been celebrated for its ability to address real-world challenges in areas such as information systems and decision making. However, with ongoing technological advancements and the increasing complexity of practical requirements, the focus has gradually shifted toward neutrosophic topology, a broader and more inclusive framework than fuzzy topology. While neutrosophic topology is primarily rooted in neutrosophic open sets, other related families, including neutrosophic pre-open sets, neutrosophic semi-open sets, and neutrosophic beta-open sets, have also proven instrumental in driving progress in this field. This study introduces neutrosophic δ-open sets as a significant enhancement to the current theoretical framework. In addition, we propose a novel category of separation axioms, termed neutrosophic δ-separation axioms, which are derived from the concept of neutrosophic δ-open sets. Moreover, we explore the interplay between these separation properties and their characteristics within subspaces. Our findings confirm that neutrosophic δ-separation axioms are reliably upheld in neutrosophic regular open subspaces. Full article
24 pages, 579 KiB  
Article
Chiral Symmetry in Dense Matter with Meson Condensation
by Takumi Muto, Toshiki Maruyama and Toshitaka Tatsumi
Symmetry 2025, 17(2), 270; https://doi.org/10.3390/sym17020270 - 10 Feb 2025
Abstract
Kaon condensation in hyperon-mixed matter [(Y+K) phase], which may be realized in neutron stars, is discussed on the basis of chiral symmetry. With the use of the effective chiral Lagrangian for kaon–baryon and kaon–kaon interactions; coupled with the relativistic [...] Read more.
Kaon condensation in hyperon-mixed matter [(Y+K) phase], which may be realized in neutron stars, is discussed on the basis of chiral symmetry. With the use of the effective chiral Lagrangian for kaon–baryon and kaon–kaon interactions; coupled with the relativistic mean field theory and universal three-baryon repulsive interaction, we clarify the effects of the s-wave kaon–baryon scalar interaction simulated by the kaon–baryon sigma terms and vector interaction (Tomozawa–Weinberg term) on kaon properties in hyperon-mixed matter, the onset density of kaon condensation, and the equation of state with the (Y+K) phase. In particular, the quark condensates in the (Y+K) phase are obtained, and their relevance to chiral symmetry restoration is discussed. Full article
(This article belongs to the Special Issue Chiral Symmetry, and Restoration in Nuclear Dense Matter)
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