Performance of a scalable quantum processor critically relies on minimizing crosstalk and unwanted interactions within the system,as it is vital for parallel controlled operations on qubits.We present a protocol not o...Performance of a scalable quantum processor critically relies on minimizing crosstalk and unwanted interactions within the system,as it is vital for parallel controlled operations on qubits.We present a protocol not only to provide information about residual coupling but also to effectively discriminate it from the influence of classical crosstalk.Our approach utilizes out-of-time-order correlators(OTOCs)as a signal of quantum crosstalk,making it applicable to various coupling forms and scalable architectures.To demonstrate the effectiveness of our protocol,we provide a theoretical analysis and simulate its implementation in coupled superconducting qubits.展开更多
We investigate the quantum entanglement in a non-Hermitian kicking system.In the Hermitian case,the out-of-time ordered correlators(OTOCs)exhibit the unbounded power-law increase with time.Correspondingly,the linear e...We investigate the quantum entanglement in a non-Hermitian kicking system.In the Hermitian case,the out-of-time ordered correlators(OTOCs)exhibit the unbounded power-law increase with time.Correspondingly,the linear entropy,which is a common measurement of entanglement,rapidly increases from zero to almost unity,indicating the formation of quantum entanglement.For strong enough non-Hermitian driving,both the OTOCs and linear entropy rapidly saturate as time evolves.Interestingly,with the increase of non-Hermitian kicking strength,the long-time averaged value of both OTOCs and linear entropy has the same transition point where they exhibit the sharp decrease from a plateau,demonstrating the disentanglment.We reveal the mechanism of disentanglement with the extension of Floquet theory to non-Hermitian systems.展开更多
The kagome lattice has garnered significant attention due to its ability to host quantum spin Fermi liquid states.Recently,the combination of unique lattice geometry,electron–electron correlations,and adjustable magn...The kagome lattice has garnered significant attention due to its ability to host quantum spin Fermi liquid states.Recently,the combination of unique lattice geometry,electron–electron correlations,and adjustable magnetism in solid kagome materials has led to the discovery of numerous fascinating quantum properties.These include unconventional superconductivity,charge and spin density waves(CDW/SDW),pair density waves(PDW),and Chern insulator phases.These emergent states are closely associated with the distinctive characteristics of the kagome lattice's electronic structure,such as van Hove singularities,Dirac fermions,and flat bands,which can exhibit exotic quasi-particle excitations under different symmetries and magnetic conditions.Recently,various quantum kagome materials have been developed,typically consisting of kagome layers stacked along the z-axis with atoms either filling the geometric centers of the kagome lattice or embedded between the layers.In this topical review,we begin by introducing the fundamental properties of several kagome materials.To gain an in-depth understanding of the relationship between topology and correlation,we then discuss the complex phenomena observed in these systems.These include the simplest kagome metal T_(3)X,kagome intercalation metal T X,and the ternary compounds AT_(6)X_(6)and RT_(3)X_(5)(A=Li,Mg,Ca,or rare earth;T=V,Cr,Mn,Fe,Co,Ni;X=Sn,Ge;R=K,Rb,Cs).Finally,we provide a perspective on future experimental work in this field.展开更多
Angle-resolved photoemission spectroscopy(ARPES)has become a cornerstone technique for elucidating the electronic structures of emergent quantum materials.Among these,kagome materials—distinguished by their two-dimen...Angle-resolved photoemission spectroscopy(ARPES)has become a cornerstone technique for elucidating the electronic structures of emergent quantum materials.Among these,kagome materials—distinguished by their two-dimensional lattice of corner-sharing triangles—provide a fertile ground for investigating exotic quantum phenomena,driven by geometric frustration,electronic correlation,and topology.In this review,we present an overview of recent ARPES studies on transition-metal kagome materials.We first outline the fundamental features of their electronic structures,including van Hove singularities,Dirac points,and flat bands,and discuss the novel quantum states that arise from many-body interactions within the kagome lattice.We then highlight key ARPES investigations into these unique electronic structures,detailing their manifestation and associated quantum states in representative kagome materials.Finally,we offer a forward-looking perspective on the potential of ARPES to uncover new quantum phenomena and its broader implications for the study of underlying physics in kagome materials.展开更多
Background Globally,suicide is the third leading cause of death among girls aged 15-19 years.However,there is a growing concern that suicide research has paid lttle attention to pregnant adolescent girls,particularly ...Background Globally,suicide is the third leading cause of death among girls aged 15-19 years.However,there is a growing concern that suicide research has paid lttle attention to pregnant adolescent girls,particularly in lowincome and middle-income countries,including Ghana,where nearly one in seven adolescents experiences(unwanted)pregnancy.Aims To assess the prevalence and correlates of suicidal ideation and suicide attempt and the self-reported reasons for attempted suicide among pregnant adolescent girls in Ghana.Methods We collected cross-sectional data(between August 2022 and December 2023)using structured anonymous questionnaires from a sample of 449 pregnant adolescent girls(aged 14-19 years)drawn from the three geographical zones of Ghana.We applied bivariable and multivariable analysis techniques to the data.Results Overall,28.51%(95%confidence interval(Cl)24.37%to 32.93%)reported suicidal ideation,and 18.04%(95%Cl 14.59%to 21.91%)reported suicide attempt during the current pregnancy.Participants who reported attempted suicide endorsed more interpersonal reasons(eg,to communicate distress,to seek help or to influence others)than intrapersonal reasons for their attempted suicide.In the final adjusted logistic regression models,food insecurity(adjusted odds ratio(aOR)=2.69;95%Cl 1.34 to 5.41;p=0.005)was uniquely associated with increased odds of suicidal ideation.Adverse childhood experiences(a0R=3.04;95%CI 1.33 to 6.97;p=0.008),history of attempted suicide before current pregnancy(a0R=3.47;95%CI 1.27 to 9.47;p=0.015)and depression(measured by the 5-item World Health Organization Well-Being Index;aOR=0.31;95%CI 0.12 to 0.77;p=0.012)were uniquely associated with increased odds of suicide attempt.Five variables were commonly associated with increased odds of both suicidal ideation and suicide attempt:conflict with parents,alcohol use,pregnancy-related anxiety,history of attempted suicide and intimate partner violence.While being in junior high school was uniquely associated with reduced odds of suicidal ideation,intimate partner's acceptance of paternity was commonly associated with reduced odds of both suicidal ideation and suicide attempt.Conclusions Although the prevalence estimates of suicidal ideation and suicide attempt in this study are comparable with known rates among non-pregnant adolescent girls in Ghana,additional research is needed to nuance our understanding of the correlates identified in this study.The evidence aiso highlights a need for both routine antepartum primary care mental health screening for suicidality and related risks and targeted prevention and intervention programmes.展开更多
Moiré superlattices have revolutionized the study of two-dimensional materials, enabling unprecedented control over their electronic, magnetic, optical, and mechanical properties. This review provides a comprehen...Moiré superlattices have revolutionized the study of two-dimensional materials, enabling unprecedented control over their electronic, magnetic, optical, and mechanical properties. This review provides a comprehensive analysis of the latest advancements in moiré physics, focusing on the formation of moiré superlattices due to rotational misalignment or lattice mismatch in two-dimensional materials. These superlattices induce flat band structures and strong correlation effects,leading to the emergence of exotic quantum phases, such as unconventional superconductivity, correlated insulating states,and fractional quantum anomalous Hall effects. The review also explores the underlying mechanisms of these phenomena and discusses the potential technological applications of moiré physics, offering insights into future research directions in this rapidly evolving field.展开更多
Detecting coupling pattern between elements in a complex system is a basic task in data-driven analysis. The trajectory for each specific element is a cooperative result of its intrinsic dynamic, its couplings with ot...Detecting coupling pattern between elements in a complex system is a basic task in data-driven analysis. The trajectory for each specific element is a cooperative result of its intrinsic dynamic, its couplings with other elements, and the environment. It is subsequently composed of many components, only some of which take part in the couplings. In this paper we present a framework to detect the component correlation pattern. Firstly, the interested trajectories are decomposed into components by using decomposing methods such as the Fourier expansion and the Wavelet transformation. Secondly, the cross-correlations between the components are calculated, resulting into a component cross-correlation matrix(network).Finally, the dominant structure in the network is identified to characterize the coupling pattern in the system. Several deterministic dynamical models turn out to be characterized with rich structures such as the clustering of the components. The pattern of correlation between respiratory(RESP) and ECG signals is composed of five sub-clusters that are mainly formed by the components in ECG signal. Interestingly, only 7 components from RESP(scattered in four sub-clusters) take part in the realization of coupling between the two signals.展开更多
We present a comprehensive electron momentum spectroscopy study on the electronic structure of trifluorobromomethane.The binding energy spectrum and electron momentum profiles of the entire outer-valence orbitals and ...We present a comprehensive electron momentum spectroscopy study on the electronic structure of trifluorobromomethane.The binding energy spectrum and electron momentum profiles of the entire outer-valence orbitals and the first inner-valence orbital along with several shake-up states were measured by using a high-sensitivity(e,2e)apparatus at an electron impact energy of 1213 eV.Theoretical calculations employing the density functional theory with B3LYP hybrid functional and the symmetry-adapted cluster configuration-interaction method were performed to interpret the experimental results.Important effects of electron correlations in the initial neutral and final ionic states on the electron momentum profiles have been observed.展开更多
Understanding the quantum critical phenomena is one of the most important and challenging tasks in condensed matter physics and the two-impurity Anderson model(TIAM) is a good starting point for this exploration. To t...Understanding the quantum critical phenomena is one of the most important and challenging tasks in condensed matter physics and the two-impurity Anderson model(TIAM) is a good starting point for this exploration. To this end,we employ the algebraic equation of motion approach to calculate the TIAM and analytically obtain the explicit singleparticle impurity Green function under the soft cut-off approximation(SCA). This approach effectively incorporates the impurity spacing as an intrinsic parameter. By solving the pole equations of the Green function, we have, for the first time, qualitatively calculated the spectral weight functions of the corresponding low-energy excitations. We find that when the impurity spacing is less than one lattice distance, the dynamic Rudermann–Kittel–Kasuya–Yosida(RKKY) interaction effectively enters, resulting in a rapid increase in the spectral weights of the RKKY phase, which ultimately surpass those of the Kondo phase;while the spectral weights of the Kondo phase are strongly suppressed. From the perspective of spectral weights, we further confirm the existence of a crossover from the Kondo phase to the RKKY phase in the TIAM. Based on these results, the reasons for the phenomenon of the Kondo resonance splitting are also discussed.展开更多
Video snapshot compressive imaging(Video SCI) modulates scenes using various encoding masks and captures compressed measurements with a low-speed camera during a single exposure. Subsequently, reconstruction algorithm...Video snapshot compressive imaging(Video SCI) modulates scenes using various encoding masks and captures compressed measurements with a low-speed camera during a single exposure. Subsequently, reconstruction algorithms restore image sequences of dynamic scenes, offering advantages such as reduced bandwidth and storage space requirements. The temporal correlation in video data is crucial for Video SCI, as it leverages the temporal relationships among frames to enhance the efficiency and quality of reconstruction algorithms, particularly for fast-moving objects.This paper discretizes video frames to create image datasets with the same data volume but differing temporal correlations. We utilized the state-of-the-art(SOTA) reconstruction framework, EfficientSCI++, to train various compressed reconstruction models with these differing temporal correlations. Evaluating the reconstruction results from these models, our simulation experiments confirm that a reduction in temporal correlation leads to decreased reconstruction accuracy. Additionally, we simulated the reconstruction outcomes of datasets devoid of temporal correlation, illustrating that models trained on non-temporal data affect the temporal feature extraction capabilities of transformers, resulting in negligible impacts on the evaluation of reconstruction results for non-temporal correlation test datasets.展开更多
Background:One-third of veterans returning from the 1990–1991 Gulf War reported a myriad of symptoms including cognitive dysfunction,skin rashes,musculoskeletal discomfort,and fatigue.This symptom cluster is now refe...Background:One-third of veterans returning from the 1990–1991 Gulf War reported a myriad of symptoms including cognitive dysfunction,skin rashes,musculoskeletal discomfort,and fatigue.This symptom cluster is now referred to as Gulf War Illness(GWI).As the underlying mechanisms of GWI have yet to be fully elucidated,diagnosis and treatment are based on symptomatic presentation.One confounding factor tied to the illness is the high presence of post-traumatic stress disorder(PTSD).Previous research efforts have demonstrated that both GWI and PTSD are associated with immunological dysfunction.As such,this research endeavor aimed to provide insight into the complex relationship between GWI symptoms,cytokine presence,and immune cell populations to pinpoint the impact of PTSD on these measures in GWI.Methods:Symptom measures were gathered through the Multidimensional fatigue inventory(MFI)and 36-item short form health survey(SF-36)scales and biological measures were obtained through cytokine&cytometry analysis.Subgrouping was conducted using Davidson Trauma Scale scores and the Structured Clinical Interview for Diagnostic and statistical manual of mental disorders(DSM)-5,into GWI with high probability of PTSD symptoms(GWIH)and GWI with low probability of PTSD symptoms(GWIL).Data was analyzed using analysis of variance(ANOVA)statistical analysis along with correlation graph analysis.We mapped correlations between immune cells and cytokine signaling measures,hormones and GWI symptom measures to identify patterns in regulation between the GWIH,GWIL,and healthy control groups.Results:GWI with comorbid PTSD symptoms resulted in poorer health outcomes compared with both healthy control(HC)and the GWIL subgroup.Significant differences were found in basophil levels of GWI compared with HC at peak exercise regardless of PTSD symptom comorbidity(ANOVA F=4.7,P=0.01)indicating its potential usage as a biomarker for general GWI from control.While the unique identification of GWI with PTSD symptoms was less clear,the GWIL subgroup was found to be delineated from both GWIH and HC on measures of IL-15 across an exercise challenge(ANOVA F>3.75,P<0.03).Additional differences in natural killer(NK)cell numbers and function highlight IL-15 as a potential biomarker of GWI in the absence of PTSD symptoms.Conclusions:We conclude that disentangling GWI and PTSD by defining trauma-based subgroups may aid in the identification of unique GWI biosignatures that can help to improve diagnosis and target treatment of GWI more effectively.展开更多
For an arbitrary solution to the Volterra lattice hierarchy,the logarithmic derivatives of the tau-function of the solution can be computed by the matrix-resolvent method.In this paper,we define a pair of wave functio...For an arbitrary solution to the Volterra lattice hierarchy,the logarithmic derivatives of the tau-function of the solution can be computed by the matrix-resolvent method.In this paper,we define a pair of wave functions of the solution and use them to give an expression of the matrix resolvent;based on this we obtain a new formula for the k-point functions for the Volterra lattice hierarchy in terms of wave functions.As an application,we give an explicit formula of k-point functions for the even GUE(Gaussian Unitary Ensemble)correlators.展开更多
We prove the equivalence between two explicit expressions for two-point Witten-Kontsevich correlators obtained by Bertola-Dubrovin-Yang and by Zograf, respectively.
Low Earth Orbit(LEO)multibeam satellites will be widely used in the next generation of satellite communication systems,whose inter-beam interference will inevitably limit the performance of the whole system.Nonlinear ...Low Earth Orbit(LEO)multibeam satellites will be widely used in the next generation of satellite communication systems,whose inter-beam interference will inevitably limit the performance of the whole system.Nonlinear precoding such as Tomlinson-Harashima precoding(THP)algorithm has been proved to be a promising technology to solve this problem,which has smaller noise amplification effect compared with linear precoding.However,the similarity of different user channels(defined as channel correlation)will degrade the performance of THP algorithm.In this paper,we qualitatively analyze the inter-beam interference in the whole process of LEO satellite over a specific coverage area,and the impact of channel correlation on Signal-to-Noise Ratio(SNR)of receivers when THP is applied.One user grouping algorithm is proposed based on the analysis of channel correlation,which could decrease the number of users with high channel correlation in each precoding group,thus improve the performance of THP.Furthermore,our algorithm is designed under the premise of co-frequency deployment and orthogonal frequency division multiplexing(OFDM),which leads to more users under severe inter-beam interference compared to the existing research on geostationary orbit satellites broadcasting systems.Simulation results show that the proposed user grouping algorithm possesses higher channel capacity and better bit error rate(BER)performance in high SNR conditions relative to existing works.展开更多
Based on the organic geochemical data and the molecular and stable carbon isotopic compositions of natural gas of the Lower Permian Fengcheng Formation in the western Central Depression of Junggar Basin,combined with ...Based on the organic geochemical data and the molecular and stable carbon isotopic compositions of natural gas of the Lower Permian Fengcheng Formation in the western Central Depression of Junggar Basin,combined with sedimentary environment analysis and hydrocarbon-generating simulation,the gas-generating potential of the Fengcheng source rock is evaluated,the distribution of large-scale effective source kitchen is described,the genetic types of natural gas are clarified,and four types of favorable exploration targets are selected.The results show that:(1)The Fengcheng Formation is a set of oil-prone source rocks,and the retained liquid hydrocarbon is conducive to late cracking into gas,with characteristics of high gas-generating potential and late accumulation;(2)The maximum thickness of Fengcheng source rock reaches 900 m.The source rock has entered the main gas-generating stage in Penyijingxi and Shawan sags,and the area with gas-generating intensity greater than 20×10^(8) m^(3)/km^(2) is approximately 6500 km^(2).(3)Around the western Central Depression,highly mature oil-type gas with light carbon isotope composition was identified to be derived from the Fengcheng source rocks mainly,while the rest was coal-derived gas from the Carboniferous source rock;(4)Four types of favorable exploration targets with exploration potential were developed in the western Central Depression which are structural traps neighboring to the source,stratigraphic traps neighboring to the source,shale-gas type within the source,and structural traps within the source.Great attention should be paid to these targets.展开更多
The complexities of the marine environment and the unique characteristics of underwater channels pose challenges in obtaining reliable signals underwater,necessitating the filtration of underwater acoustic noise.Herei...The complexities of the marine environment and the unique characteristics of underwater channels pose challenges in obtaining reliable signals underwater,necessitating the filtration of underwater acoustic noise.Herein,an underwater acoustic signal denoising method based on ensemble empirical mode decomposition(EEMD),correlation coefficient(CC),permutation entropy(PE),and wavelet threshold denoising(WTD)is proposed.Furthermore,simulation experiments are conducted using simulated and real underwater acoustic data.The experimental results reveal that the proposed denoising method outperforms other previous methods in terms of signal-to-noise ratio,root mean square error,and CC.The proposed method eliminates noise and retains valuable information in the signal.展开更多
Scattering experiments become increasingly popular in modern scientific research,including the areas of materials,biology,chemistry,physics,etc.Besides,various types of scattering facilities have been developed recent...Scattering experiments become increasingly popular in modern scientific research,including the areas of materials,biology,chemistry,physics,etc.Besides,various types of scattering facilities have been developed recently,such as labbased x-ray scattering equipment,national synchrotron facilities and large neutron facilities.These above-mentioned trends bring up fast-increasing data amounts of scattering data,as well as different scattering types(x-ray,neutron,laser and even microwaves).To help researchers process and analyze scattering data more efficiently,we developed a general and model-free scattering data analysis software based on matrix operation,which has the unique advantage of high throughput scattering data processing,analysis and visualization.To maximize generality and efficiency,data processing is performed based on a three-dimensional matrix,where scattering curves are saved as matrices or vectors,rather than the traditional definition of paired values.It can not only realize image batch processing,background subtraction and correction,but also analyze data according to scattering theory and model,such as radius of gyration,fractal dimension and other physical quantities.In the aspect of visualization,the software allows the modify the color maps of two-dimensional scattering images and the gradual color variation of one-dimensional curves to suit efficient data communications.In all,this new software can work as a stand-alone platform for researchers to process,analyze and visualize scattering data from different research facilities without considering different file types or formats.All codes in this manuscript are open-sourced and can be easily implemented in matrix-based software,such as MATLAB,Python and Igor.展开更多
Flaxseed lignan macromolecules(FLM)are a class of important secondary metabolites in fl axseed,which have been widely concerned due to their biological and pharmacological properties,especially for their antioxidative...Flaxseed lignan macromolecules(FLM)are a class of important secondary metabolites in fl axseed,which have been widely concerned due to their biological and pharmacological properties,especially for their antioxidative activity.For the composition and structure of FLM,our results confirmed that ferulic acid glycoside(FerAG)was directly ester-linked with herbacetin diglucoside(HDG)or pinoresinol diglucoside(PDG),which might determine the beginning of FLM biosynthesis.Additionally,p-coumaric acid glycoside(CouAG)might determine the end of chain extension during FLM synthesis in fl axseed.FLM exhibited higher antioxidative activity in polar systems,as shown by its superior 1,1-diphenyl-2-picrylhydrazyl(DPPH)free radical scavenging capacity compared to the 2,2’-azinobis(3-ehtylbenzothiazolin-6-sulfnic acid)(ABTS)cation free radical scavenging capacity in non-polar systems.Moreover,the antioxidative activity of FLM was found to be highly dependent on its composition and structure.In particular,it was positively correlated with the number of phenolic hydroxyl groups(longer FLM chains)and inversely related to the steric hindrance at the ends(lower levels of FerAG and CouAG).These fi ndings verifi ed the potential application of FLM in nonpolar systems,particularly in functional food emulsions。展开更多
Accurate prediction of the frictional pressure drop is important for the design and operation of subsea oil and gas transporting system considering the length of the pipeline. The applicability of the correlations to ...Accurate prediction of the frictional pressure drop is important for the design and operation of subsea oil and gas transporting system considering the length of the pipeline. The applicability of the correlations to pipeline-riser flow needs evaluation since the flow condition in pipeline-riser is quite different from the original data where they were derived from. In the present study, a comprehensive evaluation of 24prevailing correlation in predicting frictional pressure drop is carried out based on experimentally measured data of air-water and air-oil two-phase flows in pipeline-riser. Experiments are performed in a system having different configuration of pipeline-riser with the inclination of the downcomer varied from-2°to-5°to investigated the effect of the elbow on the frictional pressure drop in the riser. The inlet gas velocity ranges from 0.03 to 6.2 m/s, and liquid velocity varies from 0.02 to 1.3 m/s. A total of885 experimental data points including 782 on air-water flows and 103 on air-oil flows are obtained and used to access the prediction ability of the correlations. Comparison of the predicted results with the measured data indicate that a majority of the investigated correlations under-predict the pressure drop on severe slugging. The result of this study highlights the requirement of new method considering the effect of pipe layout on the frictional pressure drop.展开更多
Betula platyphylla and Betula costata are important species in mixed broadleaved-Korean pine(Pinus koraiensis)forests.However,the specific ways in which their growth is affected by warm temperatures and drought remain...Betula platyphylla and Betula costata are important species in mixed broadleaved-Korean pine(Pinus koraiensis)forests.However,the specific ways in which their growth is affected by warm temperatures and drought remain unclear.To address this issue,60 and 62 tree-ring cores of B.platyphylla and B.costata were collected in Yichun,China.Using dendrochronological methods,the response and adaptation of these species to climate change were examined.A“hysteresis effect”was found in the rings of both species,linked to May–September moisture conditions of the previous year.Radial growth of B.costata was positively correlated with the standardized precipitation-evapotranspiration index(SPEI),the precipitation from September to October of the previous year,and the relative humidity in October of the previous year.Growth of B.costata is primarily restricted by moisture conditions from September to October.In contrast,B.platyphylla growth is mainly limited by minimum temperatures in May–June of both the previous and current years.After droughts,B.platyphylla had a faster recovery rate compared to B.costata.In the context of rising temperatures since 1980,the correlation between B.platyphylla growth and monthly SPEI became positive and strengthened over time,while the growth of B.costata showed no conspicuous change.Our findings suggest that the growth of B.platyphylla is already affected by warming temperatures,whereas B.costata may become limited if warming continues or intensifies.Climate change could disrupt the succession of these species,possibly accelerating the succession of pioneer species.The results of this research are of great significance for understanding how the growth changes of birch species under warming and drying conditions,and contribute to understanding the structural adaptation of mixed broadleaved-Korean pine(Pinus koraiensis)forests under climate change.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12074179 and U21A20436)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0301702)+1 种基金the Natural Science Foundation of Jiangsu Province,China(Grant Nos.BE2021015-1 and BK20232002)the Natural Science Foundation of Shandong Province(Grant No.ZR2023LZH002).
文摘Performance of a scalable quantum processor critically relies on minimizing crosstalk and unwanted interactions within the system,as it is vital for parallel controlled operations on qubits.We present a protocol not only to provide information about residual coupling but also to effectively discriminate it from the influence of classical crosstalk.Our approach utilizes out-of-time-order correlators(OTOCs)as a signal of quantum crosstalk,making it applicable to various coupling forms and scalable architectures.To demonstrate the effectiveness of our protocol,we provide a theoretical analysis and simulate its implementation in coupled superconducting qubits.
基金supported by the National Natural Science Foundation of China (Grant No. 12065009)supported by the National Natural Science Foundation of China (Grant Nos. 11704132, 11874017, and U1830111)+2 种基金Science and Technology Planning Project of Ganzhou City (Grant No. 202101095077)the Natural Science Foundation of Guangdong Province, China (Grant No. 2021A1515012350)the KPST of Guangzhou (Grant No. 201804020055)
文摘We investigate the quantum entanglement in a non-Hermitian kicking system.In the Hermitian case,the out-of-time ordered correlators(OTOCs)exhibit the unbounded power-law increase with time.Correspondingly,the linear entropy,which is a common measurement of entanglement,rapidly increases from zero to almost unity,indicating the formation of quantum entanglement.For strong enough non-Hermitian driving,both the OTOCs and linear entropy rapidly saturate as time evolves.Interestingly,with the increase of non-Hermitian kicking strength,the long-time averaged value of both OTOCs and linear entropy has the same transition point where they exhibit the sharp decrease from a plateau,demonstrating the disentanglment.We reveal the mechanism of disentanglement with the extension of Floquet theory to non-Hermitian systems.
基金Project supported by the National Natural Science Foundation of China(Grant No.12204536)the Fundamental Research Funds for the Central Universitiesthe Research Funds of People’s Public Security University of China(PPSUC)(Grant No.2023JKF02ZK09)。
文摘The kagome lattice has garnered significant attention due to its ability to host quantum spin Fermi liquid states.Recently,the combination of unique lattice geometry,electron–electron correlations,and adjustable magnetism in solid kagome materials has led to the discovery of numerous fascinating quantum properties.These include unconventional superconductivity,charge and spin density waves(CDW/SDW),pair density waves(PDW),and Chern insulator phases.These emergent states are closely associated with the distinctive characteristics of the kagome lattice's electronic structure,such as van Hove singularities,Dirac fermions,and flat bands,which can exhibit exotic quasi-particle excitations under different symmetries and magnetic conditions.Recently,various quantum kagome materials have been developed,typically consisting of kagome layers stacked along the z-axis with atoms either filling the geometric centers of the kagome lattice or embedded between the layers.In this topical review,we begin by introducing the fundamental properties of several kagome materials.To gain an in-depth understanding of the relationship between topology and correlation,we then discuss the complex phenomena observed in these systems.These include the simplest kagome metal T_(3)X,kagome intercalation metal T X,and the ternary compounds AT_(6)X_(6)and RT_(3)X_(5)(A=Li,Mg,Ca,or rare earth;T=V,Cr,Mn,Fe,Co,Ni;X=Sn,Ge;R=K,Rb,Cs).Finally,we provide a perspective on future experimental work in this field.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12488201,12074411,12374066,12374154,and 12494593)the National Key Research and Development Program of China(Grant No.2022YFA1403900,2021YFA1401800,2022YFA1604200,2023YFA1406002,2024YFA1408301,and 2024YFA1400026)+3 种基金the Strategic Priority Research Program(B)of the Chinese Academy of Sciences(Grant Nos.XDB25000000 and XDB33000000)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0301800)the Youth Innovation Promotion Association of CAS(Grant No.Y2021006)Synergetic Extreme Condition User Facility(SECUF).
文摘Angle-resolved photoemission spectroscopy(ARPES)has become a cornerstone technique for elucidating the electronic structures of emergent quantum materials.Among these,kagome materials—distinguished by their two-dimensional lattice of corner-sharing triangles—provide a fertile ground for investigating exotic quantum phenomena,driven by geometric frustration,electronic correlation,and topology.In this review,we present an overview of recent ARPES studies on transition-metal kagome materials.We first outline the fundamental features of their electronic structures,including van Hove singularities,Dirac points,and flat bands,and discuss the novel quantum states that arise from many-body interactions within the kagome lattice.We then highlight key ARPES investigations into these unique electronic structures,detailing their manifestation and associated quantum states in representative kagome materials.Finally,we offer a forward-looking perspective on the potential of ARPES to uncover new quantum phenomena and its broader implications for the study of underlying physics in kagome materials.
基金the Global WACh Rising Star Seed Award by the Department of Global Health,University of Washington,Seattle,USA(Grant No:UW/GWACh/RSA/2023-01)。
文摘Background Globally,suicide is the third leading cause of death among girls aged 15-19 years.However,there is a growing concern that suicide research has paid lttle attention to pregnant adolescent girls,particularly in lowincome and middle-income countries,including Ghana,where nearly one in seven adolescents experiences(unwanted)pregnancy.Aims To assess the prevalence and correlates of suicidal ideation and suicide attempt and the self-reported reasons for attempted suicide among pregnant adolescent girls in Ghana.Methods We collected cross-sectional data(between August 2022 and December 2023)using structured anonymous questionnaires from a sample of 449 pregnant adolescent girls(aged 14-19 years)drawn from the three geographical zones of Ghana.We applied bivariable and multivariable analysis techniques to the data.Results Overall,28.51%(95%confidence interval(Cl)24.37%to 32.93%)reported suicidal ideation,and 18.04%(95%Cl 14.59%to 21.91%)reported suicide attempt during the current pregnancy.Participants who reported attempted suicide endorsed more interpersonal reasons(eg,to communicate distress,to seek help or to influence others)than intrapersonal reasons for their attempted suicide.In the final adjusted logistic regression models,food insecurity(adjusted odds ratio(aOR)=2.69;95%Cl 1.34 to 5.41;p=0.005)was uniquely associated with increased odds of suicidal ideation.Adverse childhood experiences(a0R=3.04;95%CI 1.33 to 6.97;p=0.008),history of attempted suicide before current pregnancy(a0R=3.47;95%CI 1.27 to 9.47;p=0.015)and depression(measured by the 5-item World Health Organization Well-Being Index;aOR=0.31;95%CI 0.12 to 0.77;p=0.012)were uniquely associated with increased odds of suicide attempt.Five variables were commonly associated with increased odds of both suicidal ideation and suicide attempt:conflict with parents,alcohol use,pregnancy-related anxiety,history of attempted suicide and intimate partner violence.While being in junior high school was uniquely associated with reduced odds of suicidal ideation,intimate partner's acceptance of paternity was commonly associated with reduced odds of both suicidal ideation and suicide attempt.Conclusions Although the prevalence estimates of suicidal ideation and suicide attempt in this study are comparable with known rates among non-pregnant adolescent girls in Ghana,additional research is needed to nuance our understanding of the correlates identified in this study.The evidence aiso highlights a need for both routine antepartum primary care mental health screening for suicidality and related risks and targeted prevention and intervention programmes.
基金Project supported by the National Key R&D Program of China (Grant No. 2019YFA0307800)the National Natural Science Foundation of China (Grant No. 12074377)+2 种基金Fundamental Research Funds for the Central Universities,the International Partnership Program of Chinese Academy of Sciences (Grant No. 211211KYSB20210007)the China Postdoctoral Science Foundation (Grant No. 2024M753465)the Postdoctoral Fellowship Program (Grade C) of China Postdoctoral Science Foundation (Grant No. GZC20241893)。
文摘Moiré superlattices have revolutionized the study of two-dimensional materials, enabling unprecedented control over their electronic, magnetic, optical, and mechanical properties. This review provides a comprehensive analysis of the latest advancements in moiré physics, focusing on the formation of moiré superlattices due to rotational misalignment or lattice mismatch in two-dimensional materials. These superlattices induce flat band structures and strong correlation effects,leading to the emergence of exotic quantum phases, such as unconventional superconductivity, correlated insulating states,and fractional quantum anomalous Hall effects. The review also explores the underlying mechanisms of these phenomena and discusses the potential technological applications of moiré physics, offering insights into future research directions in this rapidly evolving field.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11875042 and 11505114)the Shanghai Project for Construction of Top Disciplines (Grant No. USST-SYS-01)。
文摘Detecting coupling pattern between elements in a complex system is a basic task in data-driven analysis. The trajectory for each specific element is a cooperative result of its intrinsic dynamic, its couplings with other elements, and the environment. It is subsequently composed of many components, only some of which take part in the couplings. In this paper we present a framework to detect the component correlation pattern. Firstly, the interested trajectories are decomposed into components by using decomposing methods such as the Fourier expansion and the Wavelet transformation. Secondly, the cross-correlations between the components are calculated, resulting into a component cross-correlation matrix(network).Finally, the dominant structure in the network is identified to characterize the coupling pattern in the system. Several deterministic dynamical models turn out to be characterized with rich structures such as the clustering of the components. The pattern of correlation between respiratory(RESP) and ECG signals is composed of five sub-clusters that are mainly formed by the components in ECG signal. Interestingly, only 7 components from RESP(scattered in four sub-clusters) take part in the realization of coupling between the two signals.
基金Project supported by the National Natural Science Foundation of China(Grant No.12127804).
文摘We present a comprehensive electron momentum spectroscopy study on the electronic structure of trifluorobromomethane.The binding energy spectrum and electron momentum profiles of the entire outer-valence orbitals and the first inner-valence orbital along with several shake-up states were measured by using a high-sensitivity(e,2e)apparatus at an electron impact energy of 1213 eV.Theoretical calculations employing the density functional theory with B3LYP hybrid functional and the symmetry-adapted cluster configuration-interaction method were performed to interpret the experimental results.Important effects of electron correlations in the initial neutral and final ionic states on the electron momentum profiles have been observed.
基金Project supported by the National Natural Science Foundation of China (Grant No. 11974420)。
文摘Understanding the quantum critical phenomena is one of the most important and challenging tasks in condensed matter physics and the two-impurity Anderson model(TIAM) is a good starting point for this exploration. To this end,we employ the algebraic equation of motion approach to calculate the TIAM and analytically obtain the explicit singleparticle impurity Green function under the soft cut-off approximation(SCA). This approach effectively incorporates the impurity spacing as an intrinsic parameter. By solving the pole equations of the Green function, we have, for the first time, qualitatively calculated the spectral weight functions of the corresponding low-energy excitations. We find that when the impurity spacing is less than one lattice distance, the dynamic Rudermann–Kittel–Kasuya–Yosida(RKKY) interaction effectively enters, resulting in a rapid increase in the spectral weights of the RKKY phase, which ultimately surpass those of the Kondo phase;while the spectral weights of the Kondo phase are strongly suppressed. From the perspective of spectral weights, we further confirm the existence of a crossover from the Kondo phase to the RKKY phase in the TIAM. Based on these results, the reasons for the phenomenon of the Kondo resonance splitting are also discussed.
基金supported in part by the National Natural Science Foundation of China (No. U23B2011)。
文摘Video snapshot compressive imaging(Video SCI) modulates scenes using various encoding masks and captures compressed measurements with a low-speed camera during a single exposure. Subsequently, reconstruction algorithms restore image sequences of dynamic scenes, offering advantages such as reduced bandwidth and storage space requirements. The temporal correlation in video data is crucial for Video SCI, as it leverages the temporal relationships among frames to enhance the efficiency and quality of reconstruction algorithms, particularly for fast-moving objects.This paper discretizes video frames to create image datasets with the same data volume but differing temporal correlations. We utilized the state-of-the-art(SOTA) reconstruction framework, EfficientSCI++, to train various compressed reconstruction models with these differing temporal correlations. Evaluating the reconstruction results from these models, our simulation experiments confirm that a reduction in temporal correlation leads to decreased reconstruction accuracy. Additionally, we simulated the reconstruction outcomes of datasets devoid of temporal correlation, illustrating that models trained on non-temporal data affect the temporal feature extraction capabilities of transformers, resulting in negligible impacts on the evaluation of reconstruction results for non-temporal correlation test datasets.
基金suppor ted by the US Depar tment of Defense Congressionally Directed Medical Research Program (CDMRP)awards (http://cdmrp.army.mil/) W81XWH-16-1-0632 (Craddock PI),W81XWH-16-1-0552 (Craddock PI),W81XWH-18-1-0549 (Sullivan PI),W81XWH-13-2-0072 (Sullivan PI),and W81XWH-09-2-0071 (Klimas PI)a Veterans Affairs Merit Award (4987.69) to Dr.Nancy Klimas。
文摘Background:One-third of veterans returning from the 1990–1991 Gulf War reported a myriad of symptoms including cognitive dysfunction,skin rashes,musculoskeletal discomfort,and fatigue.This symptom cluster is now referred to as Gulf War Illness(GWI).As the underlying mechanisms of GWI have yet to be fully elucidated,diagnosis and treatment are based on symptomatic presentation.One confounding factor tied to the illness is the high presence of post-traumatic stress disorder(PTSD).Previous research efforts have demonstrated that both GWI and PTSD are associated with immunological dysfunction.As such,this research endeavor aimed to provide insight into the complex relationship between GWI symptoms,cytokine presence,and immune cell populations to pinpoint the impact of PTSD on these measures in GWI.Methods:Symptom measures were gathered through the Multidimensional fatigue inventory(MFI)and 36-item short form health survey(SF-36)scales and biological measures were obtained through cytokine&cytometry analysis.Subgrouping was conducted using Davidson Trauma Scale scores and the Structured Clinical Interview for Diagnostic and statistical manual of mental disorders(DSM)-5,into GWI with high probability of PTSD symptoms(GWIH)and GWI with low probability of PTSD symptoms(GWIL).Data was analyzed using analysis of variance(ANOVA)statistical analysis along with correlation graph analysis.We mapped correlations between immune cells and cytokine signaling measures,hormones and GWI symptom measures to identify patterns in regulation between the GWIH,GWIL,and healthy control groups.Results:GWI with comorbid PTSD symptoms resulted in poorer health outcomes compared with both healthy control(HC)and the GWIL subgroup.Significant differences were found in basophil levels of GWI compared with HC at peak exercise regardless of PTSD symptom comorbidity(ANOVA F=4.7,P=0.01)indicating its potential usage as a biomarker for general GWI from control.While the unique identification of GWI with PTSD symptoms was less clear,the GWIL subgroup was found to be delineated from both GWIH and HC on measures of IL-15 across an exercise challenge(ANOVA F>3.75,P<0.03).Additional differences in natural killer(NK)cell numbers and function highlight IL-15 as a potential biomarker of GWI in the absence of PTSD symptoms.Conclusions:We conclude that disentangling GWI and PTSD by defining trauma-based subgroups may aid in the identification of unique GWI biosignatures that can help to improve diagnosis and target treatment of GWI more effectively.
基金supported by the National Key R and D Program of China(2020YFA0713100).
文摘For an arbitrary solution to the Volterra lattice hierarchy,the logarithmic derivatives of the tau-function of the solution can be computed by the matrix-resolvent method.In this paper,we define a pair of wave functions of the solution and use them to give an expression of the matrix resolvent;based on this we obtain a new formula for the k-point functions for the Volterra lattice hierarchy in terms of wave functions.As an application,we give an explicit formula of k-point functions for the even GUE(Gaussian Unitary Ensemble)correlators.
文摘We prove the equivalence between two explicit expressions for two-point Witten-Kontsevich correlators obtained by Bertola-Dubrovin-Yang and by Zograf, respectively.
基金supported by the Key R&D Project of the Ministry of Science and Technology of China(2020YFB1808005)。
文摘Low Earth Orbit(LEO)multibeam satellites will be widely used in the next generation of satellite communication systems,whose inter-beam interference will inevitably limit the performance of the whole system.Nonlinear precoding such as Tomlinson-Harashima precoding(THP)algorithm has been proved to be a promising technology to solve this problem,which has smaller noise amplification effect compared with linear precoding.However,the similarity of different user channels(defined as channel correlation)will degrade the performance of THP algorithm.In this paper,we qualitatively analyze the inter-beam interference in the whole process of LEO satellite over a specific coverage area,and the impact of channel correlation on Signal-to-Noise Ratio(SNR)of receivers when THP is applied.One user grouping algorithm is proposed based on the analysis of channel correlation,which could decrease the number of users with high channel correlation in each precoding group,thus improve the performance of THP.Furthermore,our algorithm is designed under the premise of co-frequency deployment and orthogonal frequency division multiplexing(OFDM),which leads to more users under severe inter-beam interference compared to the existing research on geostationary orbit satellites broadcasting systems.Simulation results show that the proposed user grouping algorithm possesses higher channel capacity and better bit error rate(BER)performance in high SNR conditions relative to existing works.
基金Supported by the National Natural Science Foundation of China(41802177,42272188)PetroChina Basic Technology Research and Development Project(2021DJ0206,2022DJ0507)Research Fund of PetroChina Basic Scientific Research and Strategic Reserve Technology(2020D-5008-04).
文摘Based on the organic geochemical data and the molecular and stable carbon isotopic compositions of natural gas of the Lower Permian Fengcheng Formation in the western Central Depression of Junggar Basin,combined with sedimentary environment analysis and hydrocarbon-generating simulation,the gas-generating potential of the Fengcheng source rock is evaluated,the distribution of large-scale effective source kitchen is described,the genetic types of natural gas are clarified,and four types of favorable exploration targets are selected.The results show that:(1)The Fengcheng Formation is a set of oil-prone source rocks,and the retained liquid hydrocarbon is conducive to late cracking into gas,with characteristics of high gas-generating potential and late accumulation;(2)The maximum thickness of Fengcheng source rock reaches 900 m.The source rock has entered the main gas-generating stage in Penyijingxi and Shawan sags,and the area with gas-generating intensity greater than 20×10^(8) m^(3)/km^(2) is approximately 6500 km^(2).(3)Around the western Central Depression,highly mature oil-type gas with light carbon isotope composition was identified to be derived from the Fengcheng source rocks mainly,while the rest was coal-derived gas from the Carboniferous source rock;(4)Four types of favorable exploration targets with exploration potential were developed in the western Central Depression which are structural traps neighboring to the source,stratigraphic traps neighboring to the source,shale-gas type within the source,and structural traps within the source.Great attention should be paid to these targets.
基金Supported by the National Natural Science Foundation of China(No.62033011)Science and Technology Project of Hebei Province(No.216Z1704G,No.20310401D)。
文摘The complexities of the marine environment and the unique characteristics of underwater channels pose challenges in obtaining reliable signals underwater,necessitating the filtration of underwater acoustic noise.Herein,an underwater acoustic signal denoising method based on ensemble empirical mode decomposition(EEMD),correlation coefficient(CC),permutation entropy(PE),and wavelet threshold denoising(WTD)is proposed.Furthermore,simulation experiments are conducted using simulated and real underwater acoustic data.The experimental results reveal that the proposed denoising method outperforms other previous methods in terms of signal-to-noise ratio,root mean square error,and CC.The proposed method eliminates noise and retains valuable information in the signal.
基金Project supported by School Project Cultivation Fund(Grant No.WK2310000101)。
文摘Scattering experiments become increasingly popular in modern scientific research,including the areas of materials,biology,chemistry,physics,etc.Besides,various types of scattering facilities have been developed recently,such as labbased x-ray scattering equipment,national synchrotron facilities and large neutron facilities.These above-mentioned trends bring up fast-increasing data amounts of scattering data,as well as different scattering types(x-ray,neutron,laser and even microwaves).To help researchers process and analyze scattering data more efficiently,we developed a general and model-free scattering data analysis software based on matrix operation,which has the unique advantage of high throughput scattering data processing,analysis and visualization.To maximize generality and efficiency,data processing is performed based on a three-dimensional matrix,where scattering curves are saved as matrices or vectors,rather than the traditional definition of paired values.It can not only realize image batch processing,background subtraction and correction,but also analyze data according to scattering theory and model,such as radius of gyration,fractal dimension and other physical quantities.In the aspect of visualization,the software allows the modify the color maps of two-dimensional scattering images and the gradual color variation of one-dimensional curves to suit efficient data communications.In all,this new software can work as a stand-alone platform for researchers to process,analyze and visualize scattering data from different research facilities without considering different file types or formats.All codes in this manuscript are open-sourced and can be easily implemented in matrix-based software,such as MATLAB,Python and Igor.
基金support from National Natural Science Foundation of China(32072267)supported by China Agriculture Research System of CRAS-14.
文摘Flaxseed lignan macromolecules(FLM)are a class of important secondary metabolites in fl axseed,which have been widely concerned due to their biological and pharmacological properties,especially for their antioxidative activity.For the composition and structure of FLM,our results confirmed that ferulic acid glycoside(FerAG)was directly ester-linked with herbacetin diglucoside(HDG)or pinoresinol diglucoside(PDG),which might determine the beginning of FLM biosynthesis.Additionally,p-coumaric acid glycoside(CouAG)might determine the end of chain extension during FLM synthesis in fl axseed.FLM exhibited higher antioxidative activity in polar systems,as shown by its superior 1,1-diphenyl-2-picrylhydrazyl(DPPH)free radical scavenging capacity compared to the 2,2’-azinobis(3-ehtylbenzothiazolin-6-sulfnic acid)(ABTS)cation free radical scavenging capacity in non-polar systems.Moreover,the antioxidative activity of FLM was found to be highly dependent on its composition and structure.In particular,it was positively correlated with the number of phenolic hydroxyl groups(longer FLM chains)and inversely related to the steric hindrance at the ends(lower levels of FerAG and CouAG).These fi ndings verifi ed the potential application of FLM in nonpolar systems,particularly in functional food emulsions。
基金the support of the Opening Fund of State Key Laboratory of Multiphase Flow in Power Engineering(SKLMF-KF-2102)。
文摘Accurate prediction of the frictional pressure drop is important for the design and operation of subsea oil and gas transporting system considering the length of the pipeline. The applicability of the correlations to pipeline-riser flow needs evaluation since the flow condition in pipeline-riser is quite different from the original data where they were derived from. In the present study, a comprehensive evaluation of 24prevailing correlation in predicting frictional pressure drop is carried out based on experimentally measured data of air-water and air-oil two-phase flows in pipeline-riser. Experiments are performed in a system having different configuration of pipeline-riser with the inclination of the downcomer varied from-2°to-5°to investigated the effect of the elbow on the frictional pressure drop in the riser. The inlet gas velocity ranges from 0.03 to 6.2 m/s, and liquid velocity varies from 0.02 to 1.3 m/s. A total of885 experimental data points including 782 on air-water flows and 103 on air-oil flows are obtained and used to access the prediction ability of the correlations. Comparison of the predicted results with the measured data indicate that a majority of the investigated correlations under-predict the pressure drop on severe slugging. The result of this study highlights the requirement of new method considering the effect of pipe layout on the frictional pressure drop.
基金the Key Project of the China National Key Research and Development Program(2021YFD2200401)the National Natural Science Foundation of China(42177421 and 41877426)。
文摘Betula platyphylla and Betula costata are important species in mixed broadleaved-Korean pine(Pinus koraiensis)forests.However,the specific ways in which their growth is affected by warm temperatures and drought remain unclear.To address this issue,60 and 62 tree-ring cores of B.platyphylla and B.costata were collected in Yichun,China.Using dendrochronological methods,the response and adaptation of these species to climate change were examined.A“hysteresis effect”was found in the rings of both species,linked to May–September moisture conditions of the previous year.Radial growth of B.costata was positively correlated with the standardized precipitation-evapotranspiration index(SPEI),the precipitation from September to October of the previous year,and the relative humidity in October of the previous year.Growth of B.costata is primarily restricted by moisture conditions from September to October.In contrast,B.platyphylla growth is mainly limited by minimum temperatures in May–June of both the previous and current years.After droughts,B.platyphylla had a faster recovery rate compared to B.costata.In the context of rising temperatures since 1980,the correlation between B.platyphylla growth and monthly SPEI became positive and strengthened over time,while the growth of B.costata showed no conspicuous change.Our findings suggest that the growth of B.platyphylla is already affected by warming temperatures,whereas B.costata may become limited if warming continues or intensifies.Climate change could disrupt the succession of these species,possibly accelerating the succession of pioneer species.The results of this research are of great significance for understanding how the growth changes of birch species under warming and drying conditions,and contribute to understanding the structural adaptation of mixed broadleaved-Korean pine(Pinus koraiensis)forests under climate change.
