Temporal logics are often adopted as basic tools to specifying mental states such as belief and goal of agents. Although there are works on non-monotonic extension of linear temporal logic (LTL) and branching time tem...Temporal logics are often adopted as basic tools to specifying mental states such as belief and goal of agents. Although there are works on non-monotonic extension of linear temporal logic (LTL) and branching time temporal logic (CTL),the non-monotonic extension of alternating-time temporal logic (ATL) which is an important kind of multi-agent cooperation logics has not been discussed yet in literature. To solve this problem,this paper proposed non-monotonic alternating-time temporal logic with belief and goal,namely N-ATL-BG,to facilitate the non-monotonic reasoning of mental states of agents. The semantic model,syntax and semantics of this new logic are developed. A model checking algorithm which can be finished in polynomial time is proposed for this new logic. Examples are given to show its usage.展开更多
The strong connection between braids and knots provides valuable insights into studying the topological state and phase classification of various physical systems.The phenomenon of non-Hermitian(NH)two-and three-band ...The strong connection between braids and knots provides valuable insights into studying the topological state and phase classification of various physical systems.The phenomenon of non-Hermitian(NH)two-and three-band braiding has received widespread attention.However,a systematic exploration and visualization of non-Abelian braiding and the associated knot transformations in four-band systems remains unexplored.Here,we propose a theoretical model of NH four-band braiding,provide its phase diagram,and establish its trivial,Abelian,and non-Abelian braiding rules.Additionally,we report on special knots,such as the Hopf and Solomon links in braided knots,and reveal that their transformations are accompanied by and mediated through exceptional points.Our work provides a detailed case for studying NH multiband braiding and knot structures in four-band systems,which could offer insights for topological photonics and analog information processing applications.展开更多
Realizing efficient and controlled state transfers is necessary for implementing a wide range of classical and quantum information protocols.Recent studies have demonstrated that both asymmetric and symmetric state tr...Realizing efficient and controlled state transfers is necessary for implementing a wide range of classical and quantum information protocols.Recent studies have demonstrated that both asymmetric and symmetric state transfers can be achieved by encircling an exceptional point(EP)in non-Hermitian(NH)systems.However,the application of this phenomenon has been restricted to scenarios where an EP exists in single-qubit systems and is associated with a specific type of dissipation.In this work,we demonstrate efficient and controlled symmetric and asymmetric Bell-state transfers by modulating system parameters within a Jaynes-Cummings model while accounting for atomic spontaneous emission and cavity decay.The effective suppression of nonadiabatic transitions enables a symmetric exchange of Bell states irrespective of the encircling direction.Furthermore,we report a counterintuitive finding:the presence of an EP is not indispensable for implementing asymmetric state transfers in NH systems.We achieve perfect asymmetric Bell-state transfers even in the absence of an EP by dynamically orbiting around an approximate EP.Our work presents an approach to effectively and reliably manipulate entangled states with both symmetric and asymmetric characteristics,through dissipation engineering in NH systems.展开更多
The integration of acoustic vortices with chiral exceptional points (CEPs) in ring cavities enables the controlled unidirectional coupling and manipulation of orbital angular momentum (OAM) modes. However, realizing m...The integration of acoustic vortices with chiral exceptional points (CEPs) in ring cavities enables the controlled unidirectional coupling and manipulation of orbital angular momentum (OAM) modes. However, realizing multiple vortex orders within a single cavity remains challenging because non-Hermitian modulations must be tailored for different OAM modes simultaneously. We propose a simple approach for constructing multiple CEPs by arranging resistive and reactive impedance-boundary modulations with specific azimuthal patterns along the inner wall of an acoustic ring cavity. This design allows for independent engineering of multiple OAM eigenmodes and their simultaneous excitation using a single monopole source. As a representative example, we demonstrate first-, second-, and third-order OAM generation in both an exact PT-symmetric cavity with balanced gain and loss and a loss-biased passive counterpart that offers additional chirality control through the chirality-reversal effect. This study provides a flexible and compact framework for generating and manipulating multi-order acoustic OAM modes on non-Hermitian platforms.展开更多
General rules of English can get you a long way, but both the beauty and the bane (本义:毒药;祸害) of English is that there are exceptions to everything. Pluralizing(使成为复数)words isn’t always a simple matter of a...General rules of English can get you a long way, but both the beauty and the bane (本义:毒药;祸害) of English is that there are exceptions to everything. Pluralizing(使成为复数)words isn’t always a simple matter of adding an s on the end, and switching(转换)a word from masculine(阳性的)form to feminine(阴性的)form isn’t always a matter of adding ess.展开更多
Despite the availability of garbage collectors, programmers must manually manage non-memory finite system resources such as file descriptors. Resource leaks can gradually consume all available resources and cause prog...Despite the availability of garbage collectors, programmers must manually manage non-memory finite system resources such as file descriptors. Resource leaks can gradually consume all available resources and cause programs to raise resource exhaustion exceptions. However, programmers commonly provide no effective recovery approach for resource exhaustion exceptions, which often causes programs to halt without completing their tasks. In this paper, we propose to automatically recover programs from resource exhaustion exceptions caused by resource leaks. We transform programs to catch resource exhaustion exceptions, collect leaked resources, and then retry the failure code. A resource collector is designed to identify leaked resources and safely release them. We implement our approach for Java programs. Experimental results show that our approach can successfully handle resource exhaustion exceptions caused by reported resource leaks and allow programs to complete their tasks with an average execution time increase of 2.52% and negligible bytecode size increase.展开更多
This paper presents a declarative semantics of compositional inheritancein an object-oriented logic programming' framework wit h explicit exceptions,based on the iterated least Aspoint semantics to normal logic pr...This paper presents a declarative semantics of compositional inheritancein an object-oriented logic programming' framework wit h explicit exceptions,based on the iterated least Aspoint semantics to normal logic programs. Tak-ing logic objects with exceptions as a ldnd of nonmonotonic theory, the nonmonotonicity of inheritance is achieved, which is of importance for modelingincomplete knowledge and requirement specffications in both artificial intelli-gence and softwa-re engineering.展开更多
As an important result of the development of digital science and technology,artificial intelligence(AI)technology has penetrated all aspects of preschool education,bringing unprecedented changes to children’s learnin...As an important result of the development of digital science and technology,artificial intelligence(AI)technology has penetrated all aspects of preschool education,bringing unprecedented changes to children’s learning and development.Based on the current situation of preschool education,the article analyzes the characteristics of the application of AI equipment in children’s preschool education,and points out that the value of its application is mainly manifested in enriching the form of play in preschool education,improving the acceptance of students,enhancing the pertinence of preschool education based on big data prediction,and enriching the means of education for special children.Under the background of the rapid development of AI technology,the article puts forward countermeasures for the development of children’s education in the era of AI,adheres to the bottom-line principle of protecting children,and forms a good AI application scenario based on children’s needs.To further cultivate children’s AI literacy and strengthen the depth of AI application in preschool education,this article helps the users of preschool education to apply AI more effectively and achieve quality improvement of preschool education.展开更多
Introduction In September 2020,President Xi Jinping announced China's goals of carbon peak and carbon neutrality.Compared to Europe and the United States,China faces a tighter timeline and a larger scale in achiev...Introduction In September 2020,President Xi Jinping announced China's goals of carbon peak and carbon neutrality.Compared to Europe and the United States,China faces a tighter timeline and a larger scale in achieving its dual carbon goals,making the task exceptionally demanding.展开更多
Topological phases featuring non-Abelian charges have garnered significant attention in recent years.In parallel,the study of multiband exceptional topology in non-Hermitian systems has emerged as a prominent research...Topological phases featuring non-Abelian charges have garnered significant attention in recent years.In parallel,the study of multiband exceptional topology in non-Hermitian systems has emerged as a prominent research direction.In this study,we investigate a parity-time(PT)symmetric Hamiltonian,which hosts both conventional non-Abelian topological phases(NATPs)and hybrid phases.We propose an experimental scheme using spin-1 atoms with spin-orbit coupling trapped in two-dimensional(2D)lattices.Before adding a non-Hermitian term,we find the emergence of distinct topological phases mixed by two NATPs and establish their connection with NATPs theory.When a non-Hermitian term that preserves PT symmetry protection was introduced,stable second-order exceptional rings and third-order exceptional points emerge and they drive the edge states to manifest as discontinuous Fermi arcs in the surface Brillouin zone.However,with the variation of the non-Hermitian term,it is rather intriguing that two types of exceptional rings here transition from being internally tangent to externally tangent,transforming into a new topological phase equivalent to the Hermitian case.This research provides deeper insights into the nature of NATPs and the topological implications of exceptional structures,contributing to the field of topological physics.展开更多
The perpetually snow-capped mountain ranges,adorned with white clouds and coexisting with the swiftly descending Yigong Tsangpo River at their bases,perfectly encapsulate Nyiwo Township in Lhari County of Nagqu City,f...The perpetually snow-capped mountain ranges,adorned with white clouds and coexisting with the swiftly descending Yigong Tsangpo River at their bases,perfectly encapsulate Nyiwo Township in Lhari County of Nagqu City,forming a picturesque landscape.Nyiwo Township is cherished and particularly nurtured by nature,allowing the entire township to enjoy exceptionally favourable seasons.展开更多
Osteoarthritis(OA)is a widespread joint disorder that has emerged as a significant global healthcare challenge.Over the past decade,advancements in material science and medicine have transformed the development of fun...Osteoarthritis(OA)is a widespread joint disorder that has emerged as a significant global healthcare challenge.Over the past decade,advancements in material science and medicine have transformed the development of functional materials aimed at addressing the complex issues associated with the diagnosis and treatment of OA.This review synthesizes the latest advancements in various types of intelligent micro-structured materials and their design principles.By examining the exceptional structural characteristics of materials with unique properties such as tailored attributes,controllability,biocompatibility,and bioactivity,we emphasize the design of composite materials for precise and early intervention in OA.This is achieved through advanced imaging techniques and machine learning-based analysis,alongside the customization of micro-structured material properties to align with the biological and mechanical requirements of specific joint tissues.This review offers an in-depth analysis of the transformative potential of advanced technologies and artificial intelligence(AI)in the development of innovative solutions for OA diagnosis and therapy.It aims to inform future research and inspire the creation of next-generation smart materials with unprecedented performance,thereby enhancing our capabilities in the prevention and treatment of OA.展开更多
We explore the parity-time(PT)-symmetry breaking transition in a dimer circuit composed of two RLC resonators that are weakly coupled via an inductor.The energy behavior of this dimer circuit is reflected in the split...We explore the parity-time(PT)-symmetry breaking transition in a dimer circuit composed of two RLC resonators that are weakly coupled via an inductor.The energy behavior of this dimer circuit is reflected in the splitting or degeneracy of the systems eigenfrequencies as the gain–loss strength varies.Its dynamical properties can be described by a non-Hermitian Hamiltonian.The eigenfrequency spectrum of the system is divided by two critical points into three distinct regions:the symmetric region,the oscillatory growth region,and the fully exponential growth region.Building upon previous work on implementing the exceptional point(EP)in circuit systems,our study focuses on further exploring the variation patterns of circuit eigenfrequencies near the EP under weak coupling conditions.In addition,we construct a corresponding Dirac point(DP)circuit system for comparison.By leveraging the unique physical properties near both the EP and the DP,we further propose potential practical applications.Using perturbation theory and system simulations,we demonstrate that the square-root eigenfrequency splitting near the EP significantly enhances the sensitivity to small external perturbations,compared to the linear splitting behavior near the DP.This study presents promising prospects for next-generation sensing technologies.展开更多
With an average elevation of over 4,500 meters and spanning 2.5 million square km,the Qinghai-Xizang Plateau is the highest and largest plateau on Earth,earning it the title the"roof of the world".Un surpris...With an average elevation of over 4,500 meters and spanning 2.5 million square km,the Qinghai-Xizang Plateau is the highest and largest plateau on Earth,earning it the title the"roof of the world".Un surprisingly,the plateau is home to exceptional biodiversity,making it one of the most biologically rich geographical regions in the world.展开更多
In this paper, we investigate the effect of exceptional points(EPs) on the violation of Leggett–Garg inequality(LGI) and no-signaling-in-time(NSIT) conditions and compare the different effects between the Hamiltonian...In this paper, we investigate the effect of exceptional points(EPs) on the violation of Leggett–Garg inequality(LGI) and no-signaling-in-time(NSIT) conditions and compare the different effects between the Hamiltonian EP(HEP) and Liouvillian EP(LEP) on those violations. We consider an open system consisting of two coupled qubits and each qubit is contacted with a thermal bath at a different temperature. In the case of omitting quantum jumps, we find that the system exhibits a second-order HEP, which separates the parameter space into an overdamped regime and an underdamped regime. In this situation, the LGI and NSIT conditions can be violated in both regimes and not violated at the HEP. In the case of without omitting quantum jumps, we find that the system exhibits a third-order LEP, which also separates the parameter space into an overdamped regime and an underdamped regime. In this situation, the LGI can only be violated in the underdamped regime with large coupling strength between the qubits.Conversely, the NSIT conditions can be violated in both regimes, as well as at the LEP, except in the overdamped regime with small coupling strength between the qubits. Comparing the violations of the LGI and NSIT conditions with HEP and LEP, we find that the quantum jumps would reduce the generation of coherence, enhance the decoherence, and lead to narrower parameter regimes that the LGI and NSIT conditions can be violated. Furthermore, in both cases,the NSIT conditions can be violated in a wider parameter regime than the LGI.展开更多
The Dicke model,which describes the collective interaction between an ensemble of atoms and a single-mode photon field,serves as a fundamental framework for studying light-matter interactions and quantum electrodynami...The Dicke model,which describes the collective interaction between an ensemble of atoms and a single-mode photon field,serves as a fundamental framework for studying light-matter interactions and quantum electrodynamic phenomena.In this work,we investigate the manifestation of non-Hermitian effects in a generalized Dicke model,where two dissipative atom ensembles interact with a single-mode photon field.We explore the system in the semiclassical limit as a non-Hermitian Dicke model,revealing rich exceptional points(EPs)and diabolic points.Furthermore,we explore the quantum signature of EPs in the Hilbert space,relying on discrete photon numbers.The transition of photons from antibunching to bunching at steady state is unravelled.Our findings deepen the understanding of non-Hermitian physics in light-matter interaction,which is instructive for the design of advanced photonic devices.展开更多
While machine learning holds remarkable potential for designing high-quality(Q)photonic crystal(PC)cavities,its effectiveness heavily relies on the availability of thousands of data samples.This requirement necessitat...While machine learning holds remarkable potential for designing high-quality(Q)photonic crystal(PC)cavities,its effectiveness heavily relies on the availability of thousands of data samples.This requirement necessitates substantial simulation resources and considerable time.To tackle the challenge of data scarcity in high-Q microcavity designs,we propose an innovative intelligent model for efficient data augmentation that entails merely a few hundred original samples.Notably,our novel structural reshaping strategy,involving the groundbreaking Euler-bend air-hole structure,significantly enhances the fabrication robustness,addressing the consistency difficulty associated with large-scale manufacturing of high-Q PC microcavity arrays.Silicon PC nanobeam cavities are experimentally demonstrated,featuring record-breaking loaded Q factors,large tolerance for the Euler-bend holes and extremely compact sizes of 6μm^(2).Importantly,to emphasize the on-chip high-resolution signal processing,the cavity-based microwave photonic filters(MPFs)offer unprecedented capabilities,including ultra-narrow bandwidths,an unlimited frequency tuning range and ultra-high rejection ratios using a micrometer-scale cavity.This breakthrough truly transcends the traditional limitations between the filter size,frequency resolution and tuning range.These exceptional characteristics position our MPFs with a cavity-based recordbreaking Q_(MPF)/S ratio(S:device size).展开更多
Developing chemically complex intermetallic alloys(CCIMAs)is considered an effective strategy for overcoming the serious brittleness of conventional intermetallic alloys,especially under a high stress level.However,mo...Developing chemically complex intermetallic alloys(CCIMAs)is considered an effective strategy for overcoming the serious brittleness of conventional intermetallic alloys,especially under a high stress level.However,most CCIMAs still struggle to achieve yield strengths exceeding gigapascals,limiting their use as reliable structural materials in many engineering fields.展开更多
The unique wave-manipulation capabilities of zero-index metamaterials(ZIMs)offer a new opportunity for realizing bound states in the continuum(BICs).However,the relationship between anomalous scattering and BICs remai...The unique wave-manipulation capabilities of zero-index metamaterials(ZIMs)offer a new opportunity for realizing bound states in the continuum(BICs).However,the relationship between anomalous scattering and BICs remains underexplored when parity–time(PT)symmetry is introduced.In this work,we demonstrate that a BIC splits into a pair of lasing modes carrying opposite topological charges by introducing PT symmetry through gain-loss cylinders embedded in ZIM layers.Theoretical analysis and numerical simulations reveal that lasing and unidirectional transparency phenomena result from the singularities and exceptional points of the scattering matrix.Moreover,exceptional points can be tuned via propagation phase modulation in the air gap,and their coalescence produces quasi-BICs with symmetric responses.This work provides a framework for manipulating BICs and topological lasing modes in non-Hermitian systems,offering new insights for designing non-Hermitian photonic devices.展开更多
基金Natural Science Foundation of Fujian Province of China ( No.2006J0316)College Scientific and Technological Project of Office of Education of Fujian Province of China ( No.JB09302)Scientific Research Foundation for Young Teachers ofFujian Agriculture and Forestry University, China (No.08B21)
文摘Temporal logics are often adopted as basic tools to specifying mental states such as belief and goal of agents. Although there are works on non-monotonic extension of linear temporal logic (LTL) and branching time temporal logic (CTL),the non-monotonic extension of alternating-time temporal logic (ATL) which is an important kind of multi-agent cooperation logics has not been discussed yet in literature. To solve this problem,this paper proposed non-monotonic alternating-time temporal logic with belief and goal,namely N-ATL-BG,to facilitate the non-monotonic reasoning of mental states of agents. The semantic model,syntax and semantics of this new logic are developed. A model checking algorithm which can be finished in polynomial time is proposed for this new logic. Examples are given to show its usage.
基金supported by the National Natural Science Foundation of China(Grant Nos.62575099,62075059,61405058)Guangdong Basic and Applied Basic Research Foundation(Grant No.2024A1515011353)+2 种基金Open Project of the State Key Laboratory of Advanced Optical Communication Systems and Networks of China(Grant No.2024GZKF20)the Natural Science Foundation of Hunan Province(Grant Nos.2020JJ4161 and 2017JJ2048)Scientific Research Foundation of Hunan Provincial Education Department(Grant No.21A0013)。
文摘The strong connection between braids and knots provides valuable insights into studying the topological state and phase classification of various physical systems.The phenomenon of non-Hermitian(NH)two-and three-band braiding has received widespread attention.However,a systematic exploration and visualization of non-Abelian braiding and the associated knot transformations in four-band systems remains unexplored.Here,we propose a theoretical model of NH four-band braiding,provide its phase diagram,and establish its trivial,Abelian,and non-Abelian braiding rules.Additionally,we report on special knots,such as the Hopf and Solomon links in braided knots,and reveal that their transformations are accompanied by and mediated through exceptional points.Our work provides a detailed case for studying NH multiband braiding and knot structures in four-band systems,which could offer insights for topological photonics and analog information processing applications.
基金supported by the National Key Research and Development Program of China(Grant No.2024YFA1408900)the National Natural Science Foundation of China(Grant Nos.12264040,12374333,and U21A20436)+2 种基金the Jiangxi Natural Science Foundation(Grant Nos.20232BCJ23022 and 20252BAC240119)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0301705)the Jiangxi Province Key Laboratory of Applied Optical Technology(Grant No.2024SSY03051)。
文摘Realizing efficient and controlled state transfers is necessary for implementing a wide range of classical and quantum information protocols.Recent studies have demonstrated that both asymmetric and symmetric state transfers can be achieved by encircling an exceptional point(EP)in non-Hermitian(NH)systems.However,the application of this phenomenon has been restricted to scenarios where an EP exists in single-qubit systems and is associated with a specific type of dissipation.In this work,we demonstrate efficient and controlled symmetric and asymmetric Bell-state transfers by modulating system parameters within a Jaynes-Cummings model while accounting for atomic spontaneous emission and cavity decay.The effective suppression of nonadiabatic transitions enables a symmetric exchange of Bell states irrespective of the encircling direction.Furthermore,we report a counterintuitive finding:the presence of an EP is not indispensable for implementing asymmetric state transfers in NH systems.We achieve perfect asymmetric Bell-state transfers even in the absence of an EP by dynamically orbiting around an approximate EP.Our work presents an approach to effectively and reliably manipulate entangled states with both symmetric and asymmetric characteristics,through dissipation engineering in NH systems.
基金supported by the National Natural Science Foundation of China (Grant Nos.92263208,12104383,12304494,and 12404534)the National Key R&D Program of China (Grant No.2022YFA1404400)+1 种基金the Basic and Frontier Exploration Project Independently Deployed by the Institute of Acoustics,Chinese Academy of Sciences (Grant No.JCQY202403)Fundamental Research Funds for the Central Universities。
文摘The integration of acoustic vortices with chiral exceptional points (CEPs) in ring cavities enables the controlled unidirectional coupling and manipulation of orbital angular momentum (OAM) modes. However, realizing multiple vortex orders within a single cavity remains challenging because non-Hermitian modulations must be tailored for different OAM modes simultaneously. We propose a simple approach for constructing multiple CEPs by arranging resistive and reactive impedance-boundary modulations with specific azimuthal patterns along the inner wall of an acoustic ring cavity. This design allows for independent engineering of multiple OAM eigenmodes and their simultaneous excitation using a single monopole source. As a representative example, we demonstrate first-, second-, and third-order OAM generation in both an exact PT-symmetric cavity with balanced gain and loss and a loss-biased passive counterpart that offers additional chirality control through the chirality-reversal effect. This study provides a flexible and compact framework for generating and manipulating multi-order acoustic OAM modes on non-Hermitian platforms.
文摘General rules of English can get you a long way, but both the beauty and the bane (本义:毒药;祸害) of English is that there are exceptions to everything. Pluralizing(使成为复数)words isn’t always a simple matter of adding an s on the end, and switching(转换)a word from masculine(阳性的)form to feminine(阴性的)form isn’t always a matter of adding ess.
基金supported by the National Natural Science Foundation of China(Nos.61379054 and 91318301)the National High-Tech R&D Program(863)of China(No.2012AA011201)
文摘Despite the availability of garbage collectors, programmers must manually manage non-memory finite system resources such as file descriptors. Resource leaks can gradually consume all available resources and cause programs to raise resource exhaustion exceptions. However, programmers commonly provide no effective recovery approach for resource exhaustion exceptions, which often causes programs to halt without completing their tasks. In this paper, we propose to automatically recover programs from resource exhaustion exceptions caused by resource leaks. We transform programs to catch resource exhaustion exceptions, collect leaked resources, and then retry the failure code. A resource collector is designed to identify leaked resources and safely release them. We implement our approach for Java programs. Experimental results show that our approach can successfully handle resource exhaustion exceptions caused by reported resource leaks and allow programs to complete their tasks with an average execution time increase of 2.52% and negligible bytecode size increase.
文摘This paper presents a declarative semantics of compositional inheritancein an object-oriented logic programming' framework wit h explicit exceptions,based on the iterated least Aspoint semantics to normal logic programs. Tak-ing logic objects with exceptions as a ldnd of nonmonotonic theory, the nonmonotonicity of inheritance is achieved, which is of importance for modelingincomplete knowledge and requirement specffications in both artificial intelli-gence and softwa-re engineering.
文摘As an important result of the development of digital science and technology,artificial intelligence(AI)technology has penetrated all aspects of preschool education,bringing unprecedented changes to children’s learning and development.Based on the current situation of preschool education,the article analyzes the characteristics of the application of AI equipment in children’s preschool education,and points out that the value of its application is mainly manifested in enriching the form of play in preschool education,improving the acceptance of students,enhancing the pertinence of preschool education based on big data prediction,and enriching the means of education for special children.Under the background of the rapid development of AI technology,the article puts forward countermeasures for the development of children’s education in the era of AI,adheres to the bottom-line principle of protecting children,and forms a good AI application scenario based on children’s needs.To further cultivate children’s AI literacy and strengthen the depth of AI application in preschool education,this article helps the users of preschool education to apply AI more effectively and achieve quality improvement of preschool education.
文摘Introduction In September 2020,President Xi Jinping announced China's goals of carbon peak and carbon neutrality.Compared to Europe and the United States,China faces a tighter timeline and a larger scale in achieving its dual carbon goals,making the task exceptionally demanding.
基金supported by the National Natural Science Foundation of China(Grant Nos.12274473 and 12135018).
文摘Topological phases featuring non-Abelian charges have garnered significant attention in recent years.In parallel,the study of multiband exceptional topology in non-Hermitian systems has emerged as a prominent research direction.In this study,we investigate a parity-time(PT)symmetric Hamiltonian,which hosts both conventional non-Abelian topological phases(NATPs)and hybrid phases.We propose an experimental scheme using spin-1 atoms with spin-orbit coupling trapped in two-dimensional(2D)lattices.Before adding a non-Hermitian term,we find the emergence of distinct topological phases mixed by two NATPs and establish their connection with NATPs theory.When a non-Hermitian term that preserves PT symmetry protection was introduced,stable second-order exceptional rings and third-order exceptional points emerge and they drive the edge states to manifest as discontinuous Fermi arcs in the surface Brillouin zone.However,with the variation of the non-Hermitian term,it is rather intriguing that two types of exceptional rings here transition from being internally tangent to externally tangent,transforming into a new topological phase equivalent to the Hermitian case.This research provides deeper insights into the nature of NATPs and the topological implications of exceptional structures,contributing to the field of topological physics.
文摘The perpetually snow-capped mountain ranges,adorned with white clouds and coexisting with the swiftly descending Yigong Tsangpo River at their bases,perfectly encapsulate Nyiwo Township in Lhari County of Nagqu City,forming a picturesque landscape.Nyiwo Township is cherished and particularly nurtured by nature,allowing the entire township to enjoy exceptionally favourable seasons.
基金supported by the National Key Research and Development Program of China(No.2023YFC2509200)the National Natural Science Foundation of China(Nos.82470998,82270995,81970956)+1 种基金Zhejiang Science Foundation for Distinguished Young Scholars(LR24H140001)The Science and Technology Department of the State Administration of Traditional Chinese Medicine and the Zhejiang Provincial Administration of Traditional Chinese Medicine jointly established the Science and Technology Plan(GZY-ZJ-KJ-24086)。
文摘Osteoarthritis(OA)is a widespread joint disorder that has emerged as a significant global healthcare challenge.Over the past decade,advancements in material science and medicine have transformed the development of functional materials aimed at addressing the complex issues associated with the diagnosis and treatment of OA.This review synthesizes the latest advancements in various types of intelligent micro-structured materials and their design principles.By examining the exceptional structural characteristics of materials with unique properties such as tailored attributes,controllability,biocompatibility,and bioactivity,we emphasize the design of composite materials for precise and early intervention in OA.This is achieved through advanced imaging techniques and machine learning-based analysis,alongside the customization of micro-structured material properties to align with the biological and mechanical requirements of specific joint tissues.This review offers an in-depth analysis of the transformative potential of advanced technologies and artificial intelligence(AI)in the development of innovative solutions for OA diagnosis and therapy.It aims to inform future research and inspire the creation of next-generation smart materials with unprecedented performance,thereby enhancing our capabilities in the prevention and treatment of OA.
基金the financial support of the Natural Science Foundation of Jiangsu Province(Grant No.BK20231320)。
文摘We explore the parity-time(PT)-symmetry breaking transition in a dimer circuit composed of two RLC resonators that are weakly coupled via an inductor.The energy behavior of this dimer circuit is reflected in the splitting or degeneracy of the systems eigenfrequencies as the gain–loss strength varies.Its dynamical properties can be described by a non-Hermitian Hamiltonian.The eigenfrequency spectrum of the system is divided by two critical points into three distinct regions:the symmetric region,the oscillatory growth region,and the fully exponential growth region.Building upon previous work on implementing the exceptional point(EP)in circuit systems,our study focuses on further exploring the variation patterns of circuit eigenfrequencies near the EP under weak coupling conditions.In addition,we construct a corresponding Dirac point(DP)circuit system for comparison.By leveraging the unique physical properties near both the EP and the DP,we further propose potential practical applications.Using perturbation theory and system simulations,we demonstrate that the square-root eigenfrequency splitting near the EP significantly enhances the sensitivity to small external perturbations,compared to the linear splitting behavior near the DP.This study presents promising prospects for next-generation sensing technologies.
文摘With an average elevation of over 4,500 meters and spanning 2.5 million square km,the Qinghai-Xizang Plateau is the highest and largest plateau on Earth,earning it the title the"roof of the world".Un surprisingly,the plateau is home to exceptional biodiversity,making it one of the most biologically rich geographical regions in the world.
基金financially supported by the National Natural Science Foundation of China (Grants Nos. 11775019 and 11875086)。
文摘In this paper, we investigate the effect of exceptional points(EPs) on the violation of Leggett–Garg inequality(LGI) and no-signaling-in-time(NSIT) conditions and compare the different effects between the Hamiltonian EP(HEP) and Liouvillian EP(LEP) on those violations. We consider an open system consisting of two coupled qubits and each qubit is contacted with a thermal bath at a different temperature. In the case of omitting quantum jumps, we find that the system exhibits a second-order HEP, which separates the parameter space into an overdamped regime and an underdamped regime. In this situation, the LGI and NSIT conditions can be violated in both regimes and not violated at the HEP. In the case of without omitting quantum jumps, we find that the system exhibits a third-order LEP, which also separates the parameter space into an overdamped regime and an underdamped regime. In this situation, the LGI can only be violated in the underdamped regime with large coupling strength between the qubits.Conversely, the NSIT conditions can be violated in both regimes, as well as at the LEP, except in the overdamped regime with small coupling strength between the qubits. Comparing the violations of the LGI and NSIT conditions with HEP and LEP, we find that the quantum jumps would reduce the generation of coherence, enhance the decoherence, and lead to narrower parameter regimes that the LGI and NSIT conditions can be violated. Furthermore, in both cases,the NSIT conditions can be violated in a wider parameter regime than the LGI.
基金supported by the National Key R&D Program of China(Grant No.2022YFA1404400)the National Natural Science Foundation of China(Grant Nos.12125504 and 12305050)+3 种基金Zhejiang Provincial Natural Science Foundation(Grant No.LZ25A050001)the Doctoral Support Program for Young Talents of the China Association for Science and Technologythe Hundred Talents Program of the Chinese Academy of Sciencesthe Natural Science Foundation of Jiangsu Higher Education Institutions of China(Grant No.23KJB140017)。
文摘The Dicke model,which describes the collective interaction between an ensemble of atoms and a single-mode photon field,serves as a fundamental framework for studying light-matter interactions and quantum electrodynamic phenomena.In this work,we investigate the manifestation of non-Hermitian effects in a generalized Dicke model,where two dissipative atom ensembles interact with a single-mode photon field.We explore the system in the semiclassical limit as a non-Hermitian Dicke model,revealing rich exceptional points(EPs)and diabolic points.Furthermore,we explore the quantum signature of EPs in the Hilbert space,relying on discrete photon numbers.The transition of photons from antibunching to bunching at steady state is unravelled.Our findings deepen the understanding of non-Hermitian physics in light-matter interaction,which is instructive for the design of advanced photonic devices.
基金supported by the National Natural Science Foundation of China(Grant No.62175220)Open Research Fund of State Key Laboratory of Materials for Integrated Circuits(Grant No.SKLJC-K2025-07)the Fundamental Research Funds for the Central Universities(Grant No.G1323525012).
文摘While machine learning holds remarkable potential for designing high-quality(Q)photonic crystal(PC)cavities,its effectiveness heavily relies on the availability of thousands of data samples.This requirement necessitates substantial simulation resources and considerable time.To tackle the challenge of data scarcity in high-Q microcavity designs,we propose an innovative intelligent model for efficient data augmentation that entails merely a few hundred original samples.Notably,our novel structural reshaping strategy,involving the groundbreaking Euler-bend air-hole structure,significantly enhances the fabrication robustness,addressing the consistency difficulty associated with large-scale manufacturing of high-Q PC microcavity arrays.Silicon PC nanobeam cavities are experimentally demonstrated,featuring record-breaking loaded Q factors,large tolerance for the Euler-bend holes and extremely compact sizes of 6μm^(2).Importantly,to emphasize the on-chip high-resolution signal processing,the cavity-based microwave photonic filters(MPFs)offer unprecedented capabilities,including ultra-narrow bandwidths,an unlimited frequency tuning range and ultra-high rejection ratios using a micrometer-scale cavity.This breakthrough truly transcends the traditional limitations between the filter size,frequency resolution and tuning range.These exceptional characteristics position our MPFs with a cavity-based recordbreaking Q_(MPF)/S ratio(S:device size).
基金financially supported by the National Natural Science Foundation of China(Nos.52222112,52101151 and 52101135)Hong Kong Research Grant Council(RGC)(No.C1020-21G)+1 种基金Shenzhen Science and Technology Program(No.RCBS20210609103202012)APT research was conducted at the Inter-University 3D APT Unit of City University of Hong Kong(CityU),which is supported by the CityU grant 9360161
文摘Developing chemically complex intermetallic alloys(CCIMAs)is considered an effective strategy for overcoming the serious brittleness of conventional intermetallic alloys,especially under a high stress level.However,most CCIMAs still struggle to achieve yield strengths exceeding gigapascals,limiting their use as reliable structural materials in many engineering fields.
基金supported by the National Natural Science Foundation of China(Grant Nos.12504361,12274313,and 62465005)the Natural Science Foundation of Guangxi(Grant No.2025GXNSFBA069179)the Guangxi Colleges and Universities Young and Middle-aged Teachers’Basic Scientific Research Ability Enhancement Project(Grant No.2025KY0093)。
文摘The unique wave-manipulation capabilities of zero-index metamaterials(ZIMs)offer a new opportunity for realizing bound states in the continuum(BICs).However,the relationship between anomalous scattering and BICs remains underexplored when parity–time(PT)symmetry is introduced.In this work,we demonstrate that a BIC splits into a pair of lasing modes carrying opposite topological charges by introducing PT symmetry through gain-loss cylinders embedded in ZIM layers.Theoretical analysis and numerical simulations reveal that lasing and unidirectional transparency phenomena result from the singularities and exceptional points of the scattering matrix.Moreover,exceptional points can be tuned via propagation phase modulation in the air gap,and their coalescence produces quasi-BICs with symmetric responses.This work provides a framework for manipulating BICs and topological lasing modes in non-Hermitian systems,offering new insights for designing non-Hermitian photonic devices.
