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Topological Corner States due to Boundary Defects
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作者 Yiqi Zhang Yuwei Hu +1 位作者 Yongdong Li Ce Shang 《Chinese Physics Letters》 2026年第1期44-48,共5页
In conventional higher-order topological insulators(HOTIs),the emergence of topological states can be explained by using the nonzero bulk polarization index.However,corner states emerge in HOTIs with incomplete bounda... In conventional higher-order topological insulators(HOTIs),the emergence of topological states can be explained by using the nonzero bulk polarization index.However,corner states emerge in HOTIs with incomplete boundary unit cells(i.e.,boundary defects)even though the bulk polarization is zero,which challenges the conventional understanding of HOTIs.Here,based on a Kekul´e-distorted honeycomb lattice with incomplete unit cells,we reveal that incomplete unit cells exhibit fractional charges through the analysis of Wannier centers by developing a compensation method and creating the concept of Wannier center domain(WCD)which is the smallest region that one Wannier center occupies.This method compensates for the missing parts of these boundary incomplete unit cells with additional WCDs to make them complete.The compensated WCDs automatically carry the corresponding charge,and this charge together with that of the incomplete unit cell constitutes the total charge of the complete unit cell after compensation.We conclude that the emergence of corner states is attributed to the filling anomaly,which is a fundamental mechanism.Our results refresh the understanding of HOTIs,especially those with structural discontinuities,and provide a novel design for topological states which have application value in producing optical functional devices. 展开更多
关键词 unit cellswe higher order topological insulators topological corner states boundary unit cells ieboundary incomplete unit cells bulk polarization index fractional charges emergence topological states
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Emotion regulation habits and emotional states of college students during lockdown:A cross-sectional survey
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作者 Shu-Xin Zhao Tao Han +7 位作者 Wei-Zhi Bi Le-Le Fei Lu-Luan Han Yu-Lin Wang Zhi-Guang Ping Chong-Jian Wang Chang-Fu Hao Yong-Juan Xin 《World Journal of Psychiatry》 2026年第1期244-255,共12页
BACKGROUND The prevalence of negative emotional states,such as anxiety and depression,has increased annually.Although personal habits are known to influence emotional regulation,the precise mechanisms underlying this ... BACKGROUND The prevalence of negative emotional states,such as anxiety and depression,has increased annually.Although personal habits are known to influence emotional regulation,the precise mechanisms underlying this relationship remain unclear.AIM To investigate emotion regulation habits impact on students negative emotions during lockdown,using the coronavirus disease 2019 pandemic as a case example.METHODS During the coronavirus disease 2019 lockdown,an online cross-sectional survey was conducted at a Chinese university.Emotional states were assessed using the Depression,Anxiety,and Stress Scale-21(DASS-21),while demographic data and emotion regulation habits were collected concurrently.Data analysis was performed using SPSS version 27.0 and includedχ^(2)-tests for intergroup comparisons,Spearman’s rank-order correlation coefficient analysis to examine associations,and stepwise linear regression modeling to explore the relationships between emotion regulation habits and emotional states.Statistical significance was set atα=0.05.RESULTS Among the 494 valid questionnaires analyzed,the prevalence rates of negative emotional states were as follows:Depression(65.0%),anxiety(69.4%),and stress(50.8%).DASS-21 scores(mean±SD)demonstrated significant symptomatology:Total(48.77±34.88),depression(16.21±12.18),anxiety(14.90±11.91),and stress(17.64±12.07).Significant positive intercorrelations were observed among all DASS-21 subscales(P<0.01).Regression analysis identified key predictors of negative emotions(P<0.05):Risk factors included late-night frequency and academic pressure,while protective factors were the frequency of parental contact and the number of same-gender friends.Additionally,compensatory spending and binge eating positively predicted all negative emotion scores(β>0,P<0.01),whereas appropriate recreational activities negatively predicted these scores(β<0,P<0.01).CONCLUSION High negative emotion prevalence occurred among confined students.Recreational activities were protective,while compensatory spending and binge eating were risk factors,necessitating guided emotion regulation. 展开更多
关键词 Emotional states Emotion regulation habits College students Coronavirus disease 2019 Lockdown PREVALENCE
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Coexistence of near-E_(F) Van Hove Singularity and in-Gap Topological Dirac Surface States in Superconducting Electrides
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作者 Yin Yang Peihan Sun +9 位作者 Ye Shen Zhijun Tu Pengcheng Ma Hongrun Zhen Tianqi Wang Longli Tian Tian Cui Hechang Lei Kai Liu Zhonghao Liu 《Chinese Physics Letters》 2026年第1期213-217,共5页
Superconducting elect rides have attracted growing attention for their potential to achieve high superconducting transition temperatures(T_(C))under pressure.However,many known elect rides are chemically reactive and ... Superconducting elect rides have attracted growing attention for their potential to achieve high superconducting transition temperatures(T_(C))under pressure.However,many known elect rides are chemically reactive and unstable,making high-quality single-crystal growth,characterization,and measurements difficult,and most do not exhibit superconductivity at ambient pressure.In contrast,La_(3) In stands out for its ambient-pressure superconductivity(T_(C)∼9.4 K)and the availability of high-quality single crystals.Here,we investigate its low-energy electronic structure using angle-resolved photoemission spectroscopy and first-principles calculations.The bands near the Fermi energy(E_(F))are mainly derived from La 5d and In 5p orbitals.A saddle point is directly observed at the Brillouin zone(BZ)boundary,while a three-dimensional Van Hove singularity crosses E_(F) at the BZ corner.First-principles calculations further reveal topological Dirac surface states within the bulk energy gap above E_(F).The coexistence of a high density of states and in-gap topological surface states near𝐸F suggests that La3In offers a promising platform for tuning superconductivity and exploring possible topological superconducting phases through doping or external pressure. 展开更多
关键词 ambient pressure superconductivity superconducting elect rides gap topological Dirac surface states La superconducting electrides near e f Van Hove singularity angle resolved photoemission spectroscopy elect rides
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Hybridization Gap and Edge States in Strained-Layer InAs/In_(0.5)Ga_(0.5)Sb Quantum Spin Hall Insulator
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作者 Wenfeng Zhang Peizhe Jia +4 位作者 Wen-kai Lou Xinghao Wang Shaokui Su Kai Chang Rui-Rui Du 《Chinese Physics Letters》 2026年第1期179-183,共5页
The hybridization gap in strained-layer InAs/In_(x)Ga_(1−x) Sb quantum spin Hall insulators(QSHIs)is significantly enhanced compared to binary InAs/GaSb QSHI structures,where the typical indium composition,x,ranges be... The hybridization gap in strained-layer InAs/In_(x)Ga_(1−x) Sb quantum spin Hall insulators(QSHIs)is significantly enhanced compared to binary InAs/GaSb QSHI structures,where the typical indium composition,x,ranges between 0.2 and 0.4.This enhancement prompts a critical question:to what extent can quantum wells(QWs)be strained while still preserving the fundamental QSHI phase?In this study,we demonstrate the controlled molecular beam epitaxial growth of highly strained-layer QWs with an indium composition of x=0.5.These structures possess a substantial compressive strain within the In_(0.5)Ga_(0.5)Sb QW.Detailed crystal structure analyses confirm the exceptional quality of the resulting epitaxial films,indicating coherent lattice structures and the absence of visible dislocations.Transport measurements further reveal that the QSHI phase in InAs/In_(0.5)Ga_(0.5)Sb QWs is robust and protected by time-reversal symmetry.Notably,the edge states in these systems exhibit giant magnetoresistance when subjected to a modest perpendicular magnetic field.This behavior is in agreement with the𝑍2 topological property predicted by the Bernevig–Hughes–Zhang model,confirming the preservation of topologically protected edge transport in the presence of enhanced bulk strain. 展开更多
关键词 strained layer quantum spin hall insulators qshis InAs Ga Sb edge states quantum wells qws be controlled molecular beam epitaxial growth hybridization gap quantum spin Hall insulator
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Interpretation of the Pathological Mechanism of Blood Stasis in Traditional Chinese Medicine in Light of Understanding of Hypercoagulable States in Modern Medicine 被引量:3
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作者 Yong Chen Yujie Zhang 《Chinese Medicine and Natural Products》 2025年第1期30-34,共5页
In both Traditional Chinese Medicine(TCM)and modern medicine,they agree that the integrity and healthy structure of the vascular endothelium are essential for normal hemodynamics.Damage to the vascular endothelium can... In both Traditional Chinese Medicine(TCM)and modern medicine,they agree that the integrity and healthy structure of the vascular endothelium are essential for normal hemodynamics.Damage to the vascular endothelium can quickly activate the extrinsic coagulation pathway by triggering the tissue factor(TF)and lead to coagulation.This damage,along with a loss of anticoagulant properties through antithrombinⅢ(ATⅢ),TF pathway inhibitors,and the protein C system,can result in a hypercoagulable state and even thrombosis.Hypercoagulability is not only a common feature of many cancers but also an important factor promoting tumor development and metastasis,which corresponds to the TCM theory of“blood stasis leading to tumors.”The pharmacological effects of heparin and aspirin have similarities with TCM's“activating blood circulation and removing blood stasis”theory in improving blood circulation,treating related diseases,and their anti-inflammatory effects. 展开更多
关键词 blood stasis hypercoagulable state THROMBOSIS HEPARIN aspirin Traditional Chinese Medicine modern medicine
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Effects of plasma screening on the^(1)P^(o)(n=3,n=4)resonance states of H-and He using the stabilization method
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作者 仲子鑫 吕柄宽 +2 位作者 姜子实 KAR Sabyasachi HO Yew Kam 《黑龙江大学自然科学学报》 2025年第4期469-487,共19页
The effects of plasma screening on the ^(1)P^(o) resonance states of H-and He below the n=3 and n=4 thresholds of the respective subsystemsare investigated using the stabilization method and correlated exponential wav... The effects of plasma screening on the ^(1)P^(o) resonance states of H-and He below the n=3 and n=4 thresholds of the respective subsystemsare investigated using the stabilization method and correlated exponential wave functions.Two plasma mediums,namely,the Debye plasma and quantum plasma environments are considered.The screened Coulomb potential(SCP)obtained from Debye-Hückel model is used to represent Debye plasma environments and the exponential cosine screened Coulomb potential(ECSCP)obtained from a modified Debye-Hückel model is used to represent quantum plasma environments.The resonance parameters(resonance positions and widths)are presented in terms of the screening parameters. 展开更多
关键词 quantum plasma Debye plasma P-wave resonance states correlated exponential wave functions stabilization method
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Hydrodynamic Performance and Structural Response of a Sharp Eagle Wave Energy Converter Platform Under Extreme Sea States 被引量:1
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作者 YUE Wan-zhen WANG Kun-lin +4 位作者 JIANG Jia-qiang SHENG Song-wei LU Wen-zhao HE Teng YANG Xian-yuan 《China Ocean Engineering》 2025年第2期373-382,共10页
This paper presents a new type of triangular Sharp Eagle wave energy converter(WEC)platform.On the basis of the linear potential flow theory and the finite element analysis method,the hydrodynamic performance and stru... This paper presents a new type of triangular Sharp Eagle wave energy converter(WEC)platform.On the basis of the linear potential flow theory and the finite element analysis method,the hydrodynamic performance and structural response of the platform are studied,considering the actual platform motion and free surface rise under extreme sea states.First,the effects of the wave frequency and direction on the wave-induced loads and dynamic responses were examined.The motion at a wave direction angle of 0°is relatively low.On this basis,the angle constrained by the two sides of the Sharp Eagle floaters should be aligned with the main wave direction to avoid significant platform motion under extreme sea states.Additionally,the structural response of the platform,including the wave-absorbing floaters,is investigated.The results highlighted that the conditions or locations where yielding,buckling,and fatigue failures occur were different.In this context,the connection area of the Sharp Eagle floaters and platform is prone to yielding failure under oblique wave action,whereas the pontoon and side of the Sharp Eagle floaters are prone to buckling failure during significant vertical motion.Additionally,fatigue damage is most likely to occur at the connection between the middle column on both sides of the Sharp Eagle floaters and the pontoons.The findings of this paper revealed an intrinsic connection between wave-induced loads and the dynamic and structural responses of the platform,which provides a useful reference for the improved design of WECs. 展开更多
关键词 wave energy converter extreme sea states finite element analysis dynamic response structural response
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Multi-hop quantum teleportation based on HSES via GHZ-like states 被引量:1
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作者 She-Xiang Jiang Xiao-Long Wei +1 位作者 Jin-Huan Li Shuai-Shuai Li 《Chinese Physics B》 2025年第1期60-70,共11页
Implementing quantum wireless multi-hop network communication is essential to improve the global quantum network system. In this paper, we employ eight-level GHZ states as quantum channels to realize multi-hop quantum... Implementing quantum wireless multi-hop network communication is essential to improve the global quantum network system. In this paper, we employ eight-level GHZ states as quantum channels to realize multi-hop quantum communication, and utilize the logical relationship between the measurements of each node to derive the unitary operation performed by the end node. The hierarchical simultaneous entanglement switching(HSES) method is adopted, resulting in a significant reduction in the consumption of classical information compared to multi-hop quantum teleportation(QT)based on general simultaneous entanglement switching(SES). In addition, the proposed protocol is simulated on the IBM Quantum Experiment platform(IBM QE). Then, the data obtained from the experiment are analyzed using quantum state tomography, which verifies the protocol's good fidelity and accuracy. Finally, by calculating fidelity, we analyze the impact of four different types of noise(phase-damping, amplitude-damping, phase-flip and bit-flip) in this protocol. 展开更多
关键词 multi-hop quantum teleportation GHZ-like state hierarchical simultaneous entanglement swapping IBM Quantum Experiment platform quantum state tomography
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Embracing Internal States:A Review of Optimization of Repetitive Transcranial Magnetic Stimulation for Treating Depression 被引量:1
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作者 Tingting Wu Qiuxuan Yu +4 位作者 Ximei Zhu Yinjiao Li Mingyue Zhang Jiahui Deng Lin Lu 《Neuroscience Bulletin》 2025年第5期866-880,共15页
Repetitive transcranial magnetic stimulation(rTMS)is a rapid and effective therapy for major depressive disorder;however,there is significant variability in therapeutic outcomes both within and across individuals,with... Repetitive transcranial magnetic stimulation(rTMS)is a rapid and effective therapy for major depressive disorder;however,there is significant variability in therapeutic outcomes both within and across individuals,with approximately 50% of patients showing no response to rTMS treatment.Many studies have personalized the stimulation parameters of rTMS(e.g.,location and intensity of stimulation)according to the anatomical and functional structure of the brain.In addition to these parameters,the internal states of the individual,such as circadian rhythm,behavior/cognition,neural oscillation,and neuroplasticity,also contribute to the variation in rTMS effects.In this review,we summarize the current literature on the interaction between rTMS and internal states.We propose two possible methods,multimodal treatment,and adaptive closed-loop treatment,to integrate patients'internal states to achieve better rTMS treatment for depression. 展开更多
关键词 DEPRESSION RTMS State dependency Personalized medicine Circadian rhythm
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Study on the variation of the permeability coefficient of soil-rock mixtures in fault zones under different stress states 被引量:1
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作者 Wenhui Tan Shuang Liang +1 位作者 Xuewen Ma Pengfei Wang 《Deep Underground Science and Engineering》 2025年第2期210-221,共12页
As the first gold mine discovered at the sea in China and the only coastal gold mine currently mined there,Sanshandao Gold Mine faces unique challenges.The mine's safety is under continual threat from its faulted ... As the first gold mine discovered at the sea in China and the only coastal gold mine currently mined there,Sanshandao Gold Mine faces unique challenges.The mine's safety is under continual threat from its faulted structure coupled with the overlying water.As the mining proceeds deeper,the risk of water inrush increases.The mine's maximum water yield reaches 15000 m3/day,which is attributable to water channels present in fault zones.Predominantly composed of soil–rock mixtures(SRM),these fault zones'seepage characteristics significantly impact water inrush risk.Consequently,investigating the seepage characteristics of SRM is of paramount importance.However,the existing literature mostly concentrates on a single stress state.Therefore,this study examined the characteristics of the permeability coefficient under three distinct stress states:osmotic,osmotic–uniaxial,and osmotic–triaxial pressure.The SRM samples utilized in this study were extracted from in situ fault zones and then reshaped in the laboratory.In addition,the micromechanical properties of the SRM samples were analyzed using computed tomography scanning.The findings reveal that the permeability coefficient is the highest under osmotic pressure and lowest under osmotic–triaxial pressure.The sensitivity coefficient shows a higher value when the rock block percentage ranges between 30%and 40%,but it falls below 1.0 when this percentage exceeds 50%under no confining pressure.Notably,rock block percentages of 40%and 60%represent the two peak points of the sensitivity coefficient under osmotic–triaxial pressure.However,SRM samples with a 40%rock block percentage consistently show the lowest permeability coefficient under all stress states.This study establishes that a power function can model the relationship between the permeability coefficient and osmotic pressure,while its relationship with axial pressure can be described using an exponential function.These insights are invaluable for developing water inrush prevention and control strategies in mining environments. 展开更多
关键词 permeability coefficient rock block percentage sensitivity analysis soil-rock mixture stress state
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Independent dual-band bound states in the continuum based on terahertz all-dielectric metasurfaces
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作者 WANG Yu LIU Yang +5 位作者 HAO Xiao-yu ZHENG Si-yu LIU Meng ZHANG Yu-ping ZHAN Yi ZHANG Hui-yun 《中国光学(中英文)》 北大核心 2025年第5期1230-1242,共13页
Compared to traditional single-frequency bound states in the continuum(BIC),dual-band BIC of-fers higher degrees of freedom and functionality.Moveover,implementing independent control of dual-band BICs can further enh... Compared to traditional single-frequency bound states in the continuum(BIC),dual-band BIC of-fers higher degrees of freedom and functionality.Moveover,implementing independent control of dual-band BICs can further enhance their advantages and maximize their performance.This study presents a design for a dielectric metasurface that achieves dual-band BICs in the terahertz(THz)range.By adjusting two asym-metry parameters of the structure,independent control of the two symmetry-protected BICs is achieved.Fur-thermore,by varying the shape of the silicon holes,the design's robustness to geometric variations is demon-strated.Finally,the test results show that the figures of merit(FOMs)for both BICs reach 109.This work provides a new approach for realizing and tuning dual-frequency BICs,offering expanded possibilities for applications in multimode lasers,nonlinear optics,multi-channel filtering,and optical sensing. 展开更多
关键词 dual-band bound states in the continuum metasurface terahertz sensing symmetry protection
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The Experimental Determination of Exchange Mass Terms in Surface States on Both Terminations of MnBi_(4)Te_(7)
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作者 Dezhi Song Fuyang Huang +3 位作者 Gang Yao Jun Zhang Ye-Ping Jiang Jin-Feng Jia 《Chinese Physics Letters》 2025年第9期132-145,共14页
The intrinsic antiferromagnetic topological insulators in the Mn-Bi-Te family,composed of superlattice-like MnBi_(2)Te_(4)/(Bi_(2)Te_(3))_(n)(n=0,1,2,3,...)layered structure,present intriguing states of matter such as... The intrinsic antiferromagnetic topological insulators in the Mn-Bi-Te family,composed of superlattice-like MnBi_(2)Te_(4)/(Bi_(2)Te_(3))_(n)(n=0,1,2,3,...)layered structure,present intriguing states of matter such as quantum anomalous Hall effect and the axion insulator.However,the surface state gap,which is the prerequisite for the observation of these states,remains elusive.Here by molecular beam epitaxy,we obtain two types of MnBi_(4)Te_(7)films with the exclusive Bi_(2)Te_(3)(BT)or MnBi_(2)Te_(4)(MBT)terminations.By scanning tunneling spectroscopy,the mass terms in the surface states are identified on both surface terminations.Experimental results reveal the existence of a hybridization gap of approximately 23 meV in surface states on the BT termination.This gap comes from the hybridization between the surface states and the spin-split states in the adjacent MBT layer.On the MBT termination,an exchange mass term of about 28±2 meV in surface states is identified by taking magnetic-field-dependent Landau level spectra as well as theoretical simulations.In addition,the mass term varies with the field in the film with a heavy BiMn doping level in the Mn layers.These findings demonstrate the existence of mass terms in surface states on both types of terminations in our epitaxial MnBi_(4)Te_(7)films investigated by local probes. 展开更多
关键词 hall effect molecular beam epitaxy surface state gapwhich surface states states matter antiferromagnetic topological insulators axion insulatorhoweverthe scanning tunneling spectroscopy
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Role of Degenerate States on Molecular Excitation by Intense Laser Pulses
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作者 Bo Li Yan Rong Liu +6 位作者 Victor Kimberg Maomao Gong Yongjun Cheng Yong Wu Jian Guo Wang Jing Chen Song Bin Zhang 《Chinese Physics Letters》 2025年第11期75-82,共8页
A singlet diatomic molecule naturally carries doubly degenerate ±Λ states when the projection of the total electronic angular momentum onto the internuclear axis is nonzero. These doubly degenerate states contri... A singlet diatomic molecule naturally carries doubly degenerate ±Λ states when the projection of the total electronic angular momentum onto the internuclear axis is nonzero. These doubly degenerate states contribute equally in conventional measurements and are thus treated the same in corresponding simulations. In this study, we demonstrate that in resonant excitation by intense laser pulses, the doubly degenerate ±Λ states must be clearly identified. This is exemplified in the X^(1)Σ → A^(1)Π transition of CO molecules. This distinction becomes especially important in the case of circularly polarized radiation. We attribute this phenomenon to the interference of electron-rotational pathways in the strong-field coupled transition with the ±Λ-state of the excited Π state. This research sheds light on the fundamental aspects of intense laser-molecule interactions when extending conventional theories. 展开更多
关键词 doubly degenerate states resonant excitation intense laser pulses degenerate states molecular excitation conventional measurements intense laser pulses singlet diatomic molecule angular momentum
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Tunable Topological Floquet Bound States in the Continuum in a Periodically Driven Double SSH Chain
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作者 Xian Duan Ruozhen Wang +3 位作者 Bo Zhu Zhi Tan Honghua Zhong Shu Chen 《Chinese Physics Letters》 2025年第9期77-87,共11页
We propose a novel approach to generate and manipulate topological Floquet bound states in the continuum(BICs)via a class of systems constructed by coupling two identical periodically driven one-dimensional Su-Schrief... We propose a novel approach to generate and manipulate topological Floquet bound states in the continuum(BICs)via a class of systems constructed by coupling two identical periodically driven one-dimensional Su-Schrieffer-Heeger chains.The formation of topological Floquet BICs can be adjusted only by tuning the driving amplitude or frequency,regardless of whether the static system has BICs or not.The interchain bias can only change the localization property of topological Floquet BICs,and a bigger bias can lead to transforming topological Floquet BICs into bound states out of the continuum(BOCs).But it does not change the topological properties of these topological Floquet states.Based on the repulsion effect of edge states,we propose to detect occurrence of topological Floquet BICs and transition point between topological Floquet BICs and BOCs using quantum walk.Our work provided a convenient and realistic approach for the experimental realization and manipulation of BICs in a single-particle quantum system. 展开更多
关键词 generate manipulate topological floquet bound states static system CONTINUUM double SSH chain class systems interchain bias floquet bicsand tunable topological floquet bound states
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Arbitrary Positioning Higher-Order Topological Boundary States in Fe Breathing-Kagome Lattices on Ag(111)
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作者 Rui-Ge Yan Zhuo-Xing Zhang +8 位作者 Tong-Zhou Ji Wen-Lin Fan Hao-Tian Li Liang Sun Bing-Feng Miao Gong Chen Rui Wang Bai-Geng Wang Hai-Feng Ding 《Chinese Physics Letters》 2025年第8期242-263,共22页
Higher-order topological insulators,which host topologically protected states at boundaries that are at least two dimensions lower than the bulk,are an emerging class of topological materials.They provide great opport... Higher-order topological insulators,which host topologically protected states at boundaries that are at least two dimensions lower than the bulk,are an emerging class of topological materials.They provide great opportunities for exploring novel topological phenomena and fascinating applications.Utilizing a low-temperature scanning tunneling microscope,we construct breathing-kagome lattices with Fe adatoms on Ag(111)and investigate their electronic properties.We observe the higher-order topological boundary states in the topological phase but not in the trivial one,which is consistent with the theory.These states are found to be robust against the removal of bulk or edge adatoms.Further,we show the arbitrary positioning of these states either at corner,edge,or bulk sites by slightly modifying their neighbors.Our study not only demonstrates the formation and robustness of the electronic higher-order topological boundary states in real atomic systems but also provides a route for controlling their positions. 展开更多
关键词 arbitrary positioning higher order topological boundary states Ag topological materialsthey Fe breathing kagome lattices higher order topological insulators fe adatoms topologically protected states
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Quantum Geometric Tensor for Mixed States Based on the Covariant Derivative
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作者 Qianyi Wang Ben Wang +1 位作者 Jun Wang Lijian Zhang 《Chinese Physics Letters》 2025年第7期171-181,共11页
The quantum geometric tensor(QGT)is a fundamental quantity for characterizing the geometric properties of quantum states and plays an essential role in elucidating various physical phenomena.The traditional QGT,defned... The quantum geometric tensor(QGT)is a fundamental quantity for characterizing the geometric properties of quantum states and plays an essential role in elucidating various physical phenomena.The traditional QGT,defned only for pure states,has limited applicability in realistic scenarios where mixed states are common.To address this limitation,we generalize the defnition of the QGT to mixed states using the purifcation bundle and the covariant derivative.Notably,our proposed defnition reduces to the traditional QGT when mixed states approach pure states.In our framework,the real and imaginary parts of this generalized QGT correspond to the Bures metric and the mean gauge curvature,respectively,endowing it with a broad range of potential applications.Additionally,using our proposed mixed-state QGT,we derive the geodesic equation applicable to mixed states.This work establishes a unifed framework for the geometric analysis of both pure and mixed states,thereby deepening our understanding of the geometric properties of quantum states. 展开更多
关键词 characterizing geometric properties quantum states purifcation bundle elucidating various physical phenomenathe covariant derivative Bures metric quantum geometric tensor qgt quantum geometric tensor mixed states
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Fast and robust production of quantum superposition states by the fractional shortcut to adiabaticity
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作者 Guan-Qiang Li Hao Guo +2 位作者 Yu-Qi Zhang Bo Yang Ping Peng 《Communications in Theoretical Physics》 2025年第1期54-64,共11页
The fractional shortcut to adiabaticity(f-STA)for the production of quantum superposition states is proposed firstly via a three-level system with aΛ-type linkage pattern and a four-level system with a tripod structu... The fractional shortcut to adiabaticity(f-STA)for the production of quantum superposition states is proposed firstly via a three-level system with aΛ-type linkage pattern and a four-level system with a tripod structure.The fast and robust production of the coherent superposition states is studied by comparing the populations for the f-STA and the fractional stimulated Raman adiabatic passage(f-STIRAP).The states with equal proportions can be produced by fixing the controllable parameters of the driving pulses at the final moment of the whole process.The effects of the pulse intensity and the time delay of the pulses on the production process are discussed by monitoring the populations on all of the quantum states.In particular,the spontaneous emission arising from the intermediate state is investigated by the quantum master equation.The result reveals that the f-STA exhibits superior advantages over the f-STIRAP in producing the superposition states. 展开更多
关键词 quantum population transfer shortcut to adiabaticity coherent superposition states dark states spontaneous emission
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Topological transmission and topological corner states combiner in all-dielectric honeycomb valley photonic crystals
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作者 Ming Sun Xiao-Fang Xu +2 位作者 Yun-Feng Shen Ya-Qing Chang Wen-Ji Zhou 《Chinese Physics B》 2025年第3期424-431,共8页
We study the topological states(TSs)of all-dielectric honeycomb valley photonic crystals(VPCs).Breaking the space inversion symmetry of the honeycomb lattice by varying the filling ratio of materials for circular ring... We study the topological states(TSs)of all-dielectric honeycomb valley photonic crystals(VPCs).Breaking the space inversion symmetry of the honeycomb lattice by varying the filling ratio of materials for circular ring dielectric columns in the unit cell,which triggers topological phase transitions and thus achieves topological edge states(TESs)and topological corner states(TCSs).The results demonstrate that this structure has efficient photon transmission characteristics and anti-scattering robustness.In particular,we have found that changing the type of edge splicing between VPCs with different topological properties produces a change in the frequency of TCSs,and then based on this phenomenon,we have used a new method of adjusting only the type of edge splicing of the structure to design a novel TCSs combiner that can integrate four TCSs with different frequencies.This work not only expands the variety and number of unexplored TCSs that may exist in a fixed photonic band gap and can be rationalized to be selectively excited in the fixed configuration.Our study provides a feasible pathway for the design of integrated optical devices in which multiple TSs coexist in a single photonic system. 展开更多
关键词 valley photonic crystals topological phase transitions topological edge states topological corner states COMBINER
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Probing the Topology of Fermionic Gaussian Mixed States with U(1)symmetry by Full Counting Statistics
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作者 Liang Mao Hui Zhai Fan Yang 《Chinese Physics Letters》 2025年第6期208-215,共8页
Topological band theory has been studied for free fermions for decades,and one of the most profound physical results is the bulk-boundary correspondence.Recently a focus in topological physics is extending topological... Topological band theory has been studied for free fermions for decades,and one of the most profound physical results is the bulk-boundary correspondence.Recently a focus in topological physics is extending topological classification to mixed states.Here,we focus on Gaussian mixed states for which the modular Hamiltonians of the density matrix are quadratic free fermion models with U(1)symmetry and can be classified by topological invariants.The bulk-boundary correspondence is then manifested as stable gapless modes of the modular Hamiltonian and degenerate spectrum of the density matrix.In this article,we show that these gapless modes can be detected by the full counting statistics,mathematically described by a function introduced as F(θ).A divergent derivative atθ=πcan be used to probe the gapless modes in the modular Hamiltonian.Based on this,a topological indicator,whose quantization to unity senses topologically nontrivial mixed states,is introduced.We present the physical intuition of these results and also demonstrate these results with concrete models in both one-and two-dimensions.Our results pave the way for revealing the physical significance of topology in mixed states. 展开更多
关键词 free fermions quadratic free fermion models modular hamiltonians density matrix gaussian mixed states topological band theory extending topological classification stable gapless fermionic gaussian mixed states
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Atomically precise M-N-C electrocatalysts for oxygen reduction:Effects of inter-site distance,metal-metal interaction,coordination environment,and spin states
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作者 Junfeng Huang Saira Ajmal +4 位作者 Anuj Kumar Jianwen Guo Mohammed Mujahid Alam Abdullah G.Al-Sehemi Ghulam Yasin 《Journal of Energy Chemistry》 2025年第2期132-155,I0004,共25页
Inspired by molecular catalysts,researchers developed atomically precise nitrogen-coordinated single or dual metal sites imbedded in graphitized carbon(M-N-C)to fully utilize metallic sites for 02activation.These cata... Inspired by molecular catalysts,researchers developed atomically precise nitrogen-coordinated single or dual metal sites imbedded in graphitized carbon(M-N-C)to fully utilize metallic sites for 02activation.These catalysts performed remarkably well in the electrocatalytic oxygen reduction reaction(ORR)due to their distinct coordination and electrical structures,Nonetheless,their maximum efficacy in practical applications has yet to be achieved.This agenda identifies tailoring the coordination environment,spin states,intersite distance,and metal-metal interaction as innovative approaches to regulate the ORR performance of these catalysts.However,it is necessary to undertake a precise assessment of these methodologies and the knowledge obtained to be implemented in the design of future M-N-C catalysts for ORR.Therefore,this review aims to analyze recent progress in M-N-C ORR catalysts,emphasizing their innovative engineering with aspects such as alteration in intersite distance,metal-metal interaction,coordination environment,and spin states.Additionally,we critically discuss how to logically monitor the atomic structure,local coordination,spin,and electronic states of M-N-C catalysts to modulate their ORR activity.We have also highlighted the challenges associated with M-N-C catalysts and proposed suggestions for their future design and fabrication. 展开更多
关键词 ELECTROCATALYSIS M-N-C electrocatalysts ORR Activity descriptors Spin states
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