9,036 results on '"Wang, ZhiWei"'
Search Results
2. The Antecedent Role of Proactive Personality in Career Self-Management
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Yu, Lulu, Fan, Weiqiao, Wang, Zhiwei, Wang, Xiaofang, and Yu, Chuan
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- 2021
- Full Text
- View/download PDF
3. DACAT: Dual-stream Adaptive Clip-aware Time Modeling for Robust Online Surgical Phase Recognition
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Yang, Kaixiang, Li, Qiang, and Wang, Zhiwei
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Computer Science - Computer Vision and Pattern Recognition - Abstract
Surgical phase recognition has become a crucial requirement in laparoscopic surgery, enabling various clinical applications like surgical risk forecasting. Current methods typically identify the surgical phase using individual frame-wise embeddings as the fundamental unit for time modeling. However, this approach is overly sensitive to current observations, often resulting in discontinuous and erroneous predictions within a complete surgical phase. In this paper, we propose DACAT, a novel dual-stream model that adaptively learns clip-aware context information to enhance the temporal relationship. In one stream, DACAT pretrains a frame encoder, caching all historical frame-wise features. In the other stream, DACAT fine-tunes a new frame encoder to extract the frame-wise feature at the current moment. Additionally, a max clip-response read-out (Max-R) module is introduced to bridge the two streams by using the current frame-wise feature to adaptively fetch the most relevant past clip from the feature cache. The clip-aware context feature is then encoded via cross-attention between the current frame and its fetched adaptive clip, and further utilized to enhance the time modeling for accurate online surgical phase recognition. The benchmark results on three public datasets, i.e., Cholec80, M2CAI16, and AutoLaparo, demonstrate the superiority of our proposed DACAT over existing state-of-the-art methods, with improvements in Jaccard scores of at least 4.5%, 4.6%, and 2.7%, respectively. Our code and models have been released at https://github.com/kk42yy/DACAT., Comment: 5 pages, 4 figures
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- 2024
4. Discovery of terahertz-frequency orbitally-coupled magnons in a kagome ferromagnet
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Che, Mengqian, Chen, Weizhao, Wang, Maoyuan, Bartram, F. Michael, Liu, Liangyang, Dong, Xuebin, Liu, Jinjin, Li, Yidian, Lin, Hao, Wang, Zhiwei, Liu, Enke, Yao, Yugui, Yuan, Zhe, Zhang, Guang-Ming, and Yang, Luyi
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Condensed Matter - Strongly Correlated Electrons - Abstract
In ferromagnetic materials, magnons - quanta of spin waves - typically resonate in the gigahertz range. Beyond conventional magnons, while theoretical studies have predicted magnons associated with orbital magnetic moments, their direct observation has remained challenging. Here, we present the discovery of two distinct terahertz orbitally-coupled magnon resonances in the topological kagome ferromagnet Co3Sn2S2. Using time-resolved Kerr rotation spectroscopy, we pinpoint two magnon resonances at 0.61 and 0.49 THz at 6 K, surpassing all previously reported magnon resonances in ferromagnets due to strong magnetocrystalline anisotropy. These dual modes originate from the strong coupling of localized spin and orbital magnetic moments. These findings unveil a novel category of magnons stemming from orbital magnetic moments, and position Co3Sn2S2 as a promising candidate for high-speed terahertz spintronic applications
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- 2024
5. Decoupling Feature Representations of Ego and Other Modalities for Incomplete Multi-modal Brain Tumor Segmentation
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Yang, Kaixiang, Shan, Wenqi, Li, Xudong, Wang, Xuan, Yang, Xikai, Wang, Xi, Heng, Pheng-Ann, Li, Qiang, and Wang, Zhiwei
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Computer Science - Computer Vision and Pattern Recognition - Abstract
Multi-modal brain tumor segmentation typically involves four magnetic resonance imaging (MRI) modalities, while incomplete modalities significantly degrade performance. Existing solutions employ explicit or implicit modality adaptation, aligning features across modalities or learning a fused feature robust to modality incompleteness. They share a common goal of encouraging each modality to express both itself and the others. However, the two expression abilities are entangled as a whole in a seamless feature space, resulting in prohibitive learning burdens. In this paper, we propose DeMoSeg to enhance the modality adaptation by Decoupling the task of representing the ego and other Modalities for robust incomplete multi-modal Segmentation. The decoupling is super lightweight by simply using two convolutions to map each modality onto four feature sub-spaces. The first sub-space expresses itself (Self-feature), while the remaining sub-spaces substitute for other modalities (Mutual-features). The Self- and Mutual-features interactively guide each other through a carefully-designed Channel-wised Sparse Self-Attention (CSSA). After that, a Radiologist-mimic Cross-modality expression Relationships (RCR) is introduced to have available modalities provide Self-feature and also `lend' their Mutual-features to compensate for the absent ones by exploiting the clinical prior knowledge. The benchmark results on BraTS2020, BraTS2018 and BraTS2015 verify the DeMoSeg's superiority thanks to the alleviated modality adaptation difficulty. Concretely, for BraTS2020, DeMoSeg increases Dice by at least 0.92%, 2.95% and 4.95% on whole tumor, tumor core and enhanced tumor regions, respectively, compared to other state-of-the-arts. Codes are at https://github.com/kk42yy/DeMoSeg, Comment: 8 pages, 4 figures
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- 2024
6. Evidence chain for time-reversal symmetry-breaking kagome superconductivity
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Deng, Hanbin, Liu, Guowei, Guguchia, Z., Yang, Tianyu, Liu, Jinjin, Wang, Zhiwei, Xie, Yaofeng, Shao, Sen, Ma, Haiyang, Liège, William, Bourdarot, Frédéric, Yan, Xiao-Yu, Qin, Hailang, Mielke III, C., Khasanov, R., Luetkens, H., Wu, Xianxin, Chang, Guoqing, Liu, Jianpeng, Christensen, Morten Holm, Kreisel, Andreas, Andersen, Brian Møller, Huang, Wen, Zhao, Yue, Bourges, Philippe, Yao, Yugui, Dai, Pengcheng, and Yin, Jia-Xin
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Condensed Matter - Superconductivity ,Condensed Matter - Materials Science - Abstract
Superconductivity and magnetism are antagonistic quantum matter, while their intertwining has long been considered in frustrated-lattice systems1-3. In this work, we utilize scanning tunneling microscopy and muon spin resonance to discover time-reversal symmetry-breaking superconductivity in kagome metal Cs(V,Ta)3Sb5, where the Cooper pairing exhibits magnetism and is modulated by it. In the magnetic channel, we observe spontaneous internal magnetism in a full-gap superconducting state. Under perturbations of inverse magnetic fields, we detect a time-reversal asymmetrical interference of Bogoliubov quasi-particles at a circular vector. At this vector, the pairing gap spontaneously modulates, which is distinct from pair density waves occurring at a point vector and consistent with the theoretical proposal of unusual interference effect under time-reversal symmetry-breaking. The correlation between internal magnetism, Bogoliubov quasi-particles, and pairing modulation provides a chain of experimental clues for time-reversal symmetry-breaking kagome superconductivity., Comment: To appear in Nature Materials (2024)
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- 2024
7. Chiral kagome superconductivity modulations with residual Fermi arcs in KV3Sb5 and CsV3Sb5
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Deng, Hanbin, Qin, Hailang, Liu, Guowei, Yang, Tianyu, Fu, Ruiqing, Zhang, Zhongyi, Wu, Xianxin, Wang, Zhiwei, Shi, Youguo, Liu, Jinjin, Liu, Hongxiong, Yan, Xiao-Yu, Song, Wei, Xu, Xitong, Zhao, Yuanyuan, Yi, Mingsheng, Xu, Gang, Hohmann, Hendrik, Holbæk, Sofie Castro, Dürrnage, Matteo, Zhou, Sen, Chang, Guoqing, Yao, Yugui, Wang, Qianghua, Guguchia, Zurab, Neupert, Titus, Thomale, Ronny, Fischer, Mark H., and Yin, Jia-Xin
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Condensed Matter - Superconductivity ,Condensed Matter - Materials Science - Abstract
Superconductivity involving finite momentum pairing can lead to spatial gap and pair density modulations, as well as Bogoliubov Fermi states within the superconducting gap. However, the experimental realization of their intertwined relations has been challenging. Here, we detect chiral kagome superconductivity modulations with residual Fermi arcs in KV3Sb5 and CsV3Sb5 by normal and Josephson scanning tunneling microscopy down to 30mK with resolved electronic energy difference at microelectronvolt level. We observe a U-shaped superconducting gap with flat residual in-gap states. This gap exhibits chiral 2 by 2 spatial modulations with magnetic field tunable chirality, which align with the chiral 2 by 2 pair density modulations observed through Josephson tunneling. These findings demonstrate a chiral pair density wave (PDW) that breaks time-reversal symmetry. Quasiparticle interference imaging of the in-gap zero-energy states reveals segmented arcs, with high-temperature data linking them to parts of the reconstructed V d-orbital states within the charge order. The detected residual Fermi arcs can be explained by the partial suppression of these d-orbital states through an interorbital 2 by 2 PDW and thus serve as candidate Bogoliubov Fermi states. Additionally, we differentiate the observed PDW order from impurity-induced gap modulations. Our observations not only uncover a chiral PDW order with orbital-selectivity, but also illuminate the fundamental space-momentum correspondence inherent in finite momentum paired superconductivity., Comment: To appear in Nature (2024)
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- 2024
8. Phase engineering of giant second harmonic generation in Bi$_2$O$_2$Se
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Lou, Zhefeng, Zhao, Yingjie, Gong, Zhihao, Zhu, Ziye, Wu, Mengqi, Wang, Tao, Wang, Jialu, Qi, Haoyu, Zuo, Huakun, Xu, Zhuokai, Shen, Jichuang, Wang, Zhiwei, Li, Lan, Xu, Shuigang, Kong, Wei, Li, Wenbin, Zheng, Xiaorui, Wang, Hua, and Lin, Xiao
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Condensed Matter - Materials Science ,Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
Two-dimensional (2D) materials with remarkable second-harmonic generation (SHG) hold promise for future on-chip nonlinear optics. Relevant materials with both giant SHG response and environmental stability are long-sought targets. Here, we demonstrate the enormous SHG from the phase engineering of a high-performance semiconductor, Bi$_2$O$_2$Se (BOS), under uniaxial strain. SHG signals captured in strained 20 nm-BOS films exceed those of NbOI$_2$ and NbOCl$_2$ of similar thickness by a factor of 10, and are four orders of magnitude higher than monolayer-MoS$_2$, resulting in a significant second-order nonlinear susceptibility on the order of 1 nm V$^{-1}$. Intriguingly, the strain enables continuous adjustment of the ferroelectric phase transition across room temperature. Consequently, an exceptionally large tunability of SHG, approximately six orders of magnitude, is achieved through strain or thermal modulation. This colossal SHG, originating from the geometric phase of Bloch wave functions and coupled with sensitive tunability through multiple approaches in this air-stable 2D semiconductor, opens new possibilities for designing chip-scale, switchable nonlinear optical devices.
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- 2024
9. Search for orbital magnetism in the kagome superconductor ${\rm CsV_3Sb_5}$ using neutron diffraction
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Liège, William, Xie, Yaofeng, Bounoua, Dalila, Sidis, Yvan, Bourdarot, Frédéric, Li, Yongkai, Wang, Zhiwei, Yin, Jia-Xin, Dai, Pengcheng, and Bourges, Philippe
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Condensed Matter - Strongly Correlated Electrons ,Condensed Matter - Superconductivity - Abstract
As many Kagome metals, the topological superconductor AV$_3$Sb$_5$ with (A = K,Rb,Cs) hosts a charge density wave . A related chiral flux phase that breaks the time-reversal symmetry has been further theoretically predicted in these materials. The flux phase is associated with loop currents that produce ordered orbital magnetic moments, which would occur at the momentum points, $\bf M$, characterizing the charge-density wave state. Polarized neutron-diffraction experiments have been performed on an assembly of single crystals of ${\rm CsV_3Sb_5}$ to search for such orbital magnetic moments. No evidence for the existence of a three-dimensionally ordered moment is found at any temperature at the first ${\bf M_1}$=(1/2,0,0) point in the Brillouin zone within an excellent experimental uncertainty, ${\it i.e.}$ ${\bf m}=0 \pm 0.01\mu_B$ per vanadium atom. However, a hint to a magnetic orbital moment is found in the second Brillouin zone at {\bf M$_2$}=(1/2,1/2,0) at the detection limit of the experiment. Some loop currents patterns flowing ${\it only}$ on vanadium triangles are able to account for this finding suggesting an ordered orbital magnetic moment of, at most, $\sim 0.02 \pm 0.01\mu_B$ per vanadium triangle., Comment: 11 figures
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- 2024
10. Evolution of Band Structure in a Kagome Superconductor Cs(V1-xCrx)3Sb5: Toward Universal Understanding of CDW and Superconducting Phase Diagrams
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Suzuki, Shuto, Kato, Takemi, Li, Yongkai, Nakayama, Kosuke, Wang, Zhiwei, Souma, Seigo, Ozawa, Kenichi, Kitamura, Miho, Horiba, Koji, Kumigashira, Hiroshi, Takahashi, Takashi, Yao, Yugui, and Sato, Takafumi
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Condensed Matter - Superconductivity ,Condensed Matter - Strongly Correlated Electrons - Abstract
Kagome superconductors AV3Sb5 (A = K, Rb, Cs) exhibit a characteristic superconducting and charge-density wave (CDW) phase diagram upon carrier doping and chemical substitution. However, the key electronic states responsible for such a phase diagram have yet to be clarified. Here we report a systematic micro-focused angle-resolved photoemission spectroscopy (ARPES) study of Cs(V1-xCrx)3Sb5 as a function of Cr content x, where Cr substitution causes monotonic reduction of superconducting and CDW transition temperatures. We found that the V-derived bands forming saddle points at the M point and Dirac nodes along high-symmetry cuts show an energy shift due to electron doping by Cr substitution, whereas the Sb-derived electron band at the Gamma point remains almost unchanged, signifying an orbital-selective band shift. We also found that band doubling associated with the emergence of three-dimensional CDW identified at x = 0 vanishes at x = 0.25, in line with the disappearance of CDW. A comparison of band diagrams among Ti-, Nb-, and Cr-substituted Cs(V1-xCrx)3Sb5 suggests the importance to simultaneously take into account the two saddle points at the M point and their proximity to the Fermi energy, to understand the complex phase diagram against carrier doping and chemical pressure., Comment: 7 pages, 4 figures
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- 2024
11. Flat bands and distinct density wave orders in correlated Kagome superconductor CsCr$_3$Sb$_5$
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Peng, Shuting, Han, Yulei, Li, Yongkai, Shen, Jianchang, Miao, Yu, Luo, Yang, Huai, Linwei, Ou, Zhipeng, Li, Hongyu, Xiang, Ziji, Liu, Zhengtai, Shen, Dawei, Hashimoto, Makoto, Lu, Donghui, Yao, Yugui, Qiao, Zhenhua, Wang, Zhiwei, and He, Junfeng
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Condensed Matter - Superconductivity ,Condensed Matter - Strongly Correlated Electrons - Abstract
Kagome metal CsV$_3$Sb$_5$ has attracted much recent attention due to the coexistence of multiple exotic orders and the associated proposals to mimic unconventional high temperature superconductors. Nevertheless, magnetism and strong electronic correlations -- two essential ingredients for unconventional superconductivity, are absent in this V-based Kagome metal. CsCr$_3$Sb$_5$ is a newly discovered Cr-based parallel of CsV$_3$Sb$_5$, in which magnetism appears with charge density wave and superconductivity at different temperature and pressure regions. Enhanced electronic correlations are also suggested by theoretical proposals due to the calculated flat bands. Here, we report angle-resolved photoemission measurements and first-principles calculations on this new material system. Electron energy bands and the associated orbitals are resolved. Flat bands are observed near the Fermi level. Doping dependent measurements on Cs(Cr$_x$V$_{1-x}$)$_3$Sb$_5$ reveal a gradually enhanced band renormalization from CsV$_3$Sb$_5$ to CsCr$_3$Sb$_5$, accompanied by distinct spatial symmetry breaking states in the phase diagram.
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- 2024
12. SALI: Short-term Alignment and Long-term Interaction Network for Colonoscopy Video Polyp Segmentation
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Hu, Qiang, Yi, Zhenyu, Zhou, Ying, Peng, Fang, Liu, Mei, Li, Qiang, and Wang, Zhiwei
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Computer Science - Computer Vision and Pattern Recognition - Abstract
Colonoscopy videos provide richer information in polyp segmentation for rectal cancer diagnosis. However, the endoscope's fast moving and close-up observing make the current methods suffer from large spatial incoherence and continuous low-quality frames, and thus yield limited segmentation accuracy. In this context, we focus on robust video polyp segmentation by enhancing the adjacent feature consistency and rebuilding the reliable polyp representation. To achieve this goal, we in this paper propose SALI network, a hybrid of Short-term Alignment Module (SAM) and Long-term Interaction Module (LIM). The SAM learns spatial-aligned features of adjacent frames via deformable convolution and further harmonizes them to capture more stable short-term polyp representation. In case of low-quality frames, the LIM stores the historical polyp representations as a long-term memory bank, and explores the retrospective relations to interactively rebuild more reliable polyp features for the current segmentation. Combing SAM and LIM, the SALI network of video segmentation shows a great robustness to the spatial variations and low-visual cues. Benchmark on the large-scale SUNSEG verifies the superiority of SALI over the current state-of-the-arts by improving Dice by 2.1%, 2.5%, 4.1% and 1.9%, for the four test sub-sets, respectively. Codes are at https://github.com/Scatteredrain/SALI., Comment: Accepted to MICCAI 2024. Code and models: https://github.com/Scatteredrain/SALI
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- 2024
13. Magnetoresistance hysteresis in the superconduting state of Kagome CsV$_3$Sb$_5$
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Le, Tian, Liu, Jinjin, Wang, Zhiwei, and Lin, Xiao
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Condensed Matter - Superconductivity ,Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed Matter - Materials Science - Abstract
The hysteresis of magnetoresistance observed in superconductors is of great interest due to its potential connection with unconventional superconductivity. In this study, we perform electrical transport measurements on Kagome superconductor CsV$_3$Sb$_5$ nanoflakes and uncover unusual hysteretic behaviour of magnetoresistance in the superconducting state. This hysteresis can be induced by applying either a large DC or AC current at temperatures ($T$) well below the superconducting transition temperature ($T_{\rm c}$). As $T$ approaches $T_{\rm c}$, similar weak hysteresis is also detected by applying a small current. Various scenarios are discussed, with particular focus on the effects of vortex pinning and the presence of time-reversal-symmtery-breaking superconducting domains. Our findings support the latter, hinting at chiral superconductivity in Kagome superconductors., Comment: 9 pages, 3 figures
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- 2024
14. Improving Paratope and Epitope Prediction by Multi-Modal Contrastive Learning and Interaction Informativeness Estimation
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Wang, Zhiwei, Wang, Yongkang, and Zhang, Wen
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Quantitative Biology - Biomolecules ,Computer Science - Machine Learning ,Quantitative Biology - Quantitative Methods - Abstract
Accurately predicting antibody-antigen binding residues, i.e., paratopes and epitopes, is crucial in antibody design. However, existing methods solely focus on uni-modal data (either sequence or structure), disregarding the complementary information present in multi-modal data, and most methods predict paratopes and epitopes separately, overlooking their specific spatial interactions. In this paper, we propose a novel Multi-modal contrastive learning and Interaction informativeness estimation-based method for Paratope and Epitope prediction, named MIPE, by using both sequence and structure data of antibodies and antigens. MIPE implements a multi-modal contrastive learning strategy, which maximizes representations of binding and non-binding residues within each modality and meanwhile aligns uni-modal representations towards effective modal representations. To exploit the spatial interaction information, MIPE also incorporates an interaction informativeness estimation that computes the estimated interaction matrices between antibodies and antigens, thereby approximating them to the actual ones. Extensive experiments demonstrate the superiority of our method compared to baselines. Additionally, the ablation studies and visualizations demonstrate the superiority of MIPE owing to the better representations acquired through multi-modal contrastive learning and the interaction patterns comprehended by the interaction informativeness estimation., Comment: This paper is accepted by IJCAI 2024
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- 2024
15. Towards Understanding How Transformer Perform Multi-step Reasoning with Matching Operation
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Wang, Zhiwei, Wang, Yunji, Zhang, Zhongwang, Zhou, Zhangchen, Jin, Hui, Hu, Tianyang, Sun, Jiacheng, Li, Zhenguo, Zhang, Yaoyu, and Xu, Zhi-Qin John
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Computer Science - Artificial Intelligence ,Computer Science - Computation and Language ,Computer Science - Machine Learning - Abstract
Large language models have consistently struggled with complex reasoning tasks, such as mathematical problem-solving. Investigating the internal reasoning mechanisms of these models can help us design better model architectures and training strategies, ultimately enhancing their reasoning capabilities. In this study, we examine the matching mechanism employed by Transformer for multi-step reasoning on a constructed dataset. We investigate factors that influence the model's matching mechanism and discover that small initialization and post-LayerNorm can facilitate the formation of the matching mechanism, thereby enhancing the model's reasoning ability. Moreover, we propose a method to improve the model's reasoning capability by adding orthogonal noise. Finally, we investigate the parallel reasoning mechanism of Transformers and propose a conjecture on the upper bound of the model's reasoning ability based on this phenomenon. These insights contribute to a deeper understanding of the reasoning processes in large language models and guide designing more effective reasoning architectures and training strategies.
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- 2024
16. Exploring Graph-based Knowledge: Multi-Level Feature Distillation via Channels Relational Graph
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Wang, Zhiwei, Huang, Jun, Ma, Longhua, Wu, Chengyu, and Ma, Hongyu
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Computer Science - Computer Vision and Pattern Recognition - Abstract
In visual tasks, large teacher models capture essential features and deep information, enhancing performance. However, distilling this information into smaller student models often leads to performance loss due to structural differences and capacity limitations. To tackle this, we propose a distillation framework based on graph knowledge, including a multi-level feature alignment strategy and an attention-guided mechanism to provide a targeted learning trajectory for the student model. We emphasize spectral embedding (SE) as a key technique in our distillation process, which merges the student's feature space with the relational knowledge and structural complexities similar to the teacher network. This method captures the teacher's understanding in a graph-based representation, enabling the student model to more accurately mimic the complex structural dependencies present in the teacher model. Compared to methods that focus only on specific distillation areas, our strategy not only considers key features within the teacher model but also endeavors to capture the relationships and interactions among feature sets, encoding these complex pieces of information into a graph structure to understand and utilize the dynamic relationships among these pieces of information from a global perspective. Experiments show that our method outperforms previous feature distillation methods on the CIFAR-100, MS-COCO, and Pascal VOC datasets, proving its efficiency and applicability.
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- 2024
17. Initialization is Critical to Whether Transformers Fit Composite Functions by Inference or Memorizing
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Zhang, Zhongwang, Lin, Pengxiao, Wang, Zhiwei, Zhang, Yaoyu, and Xu, Zhi-Qin John
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Computer Science - Machine Learning - Abstract
Transformers have shown impressive capabilities across various tasks, but their performance on compositional problems remains a topic of debate. In this work, we investigate the mechanisms of how transformers behave on unseen compositional tasks. We discover that the parameter initialization scale plays a critical role in determining whether the model learns inferential solutions, which capture the underlying compositional primitives, or symmetric solutions, which simply memorize mappings without understanding the compositional structure. By analyzing the information flow and vector representations within the model, we reveal the distinct mechanisms underlying these solution types. We further find that inferential solutions exhibit low complexity bias, which we hypothesize is a key factor enabling them to learn individual mappings for single anchors. Building upon the understanding of these mechanisms, we can predict the learning behavior of models with different initialization scales when faced with data of varying complexity. Our findings provide valuable insights into the role of initialization scale in shaping the type of solution learned by transformers and their ability to learn and generalize compositional tasks.
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- 2024
18. Three-dimensional hidden phase probed by in-plane magnetotransport in kagome metal CsV$_3$Sb$_5$ thin flakes
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Wei, Xinjian, Tian, Congkuan, Cui, Hang, Zhai, Yuxin, Li, Yongkai, Liu, Shaobo, Song, Yuanjun, Feng, Ya, Huang, Miaoling, Wang, Zhiwei, Liu, Yi, Xiong, Qihua, Yao, Yugui, Xie, X. C., and Chen, Jian-Hao
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Condensed Matter - Strongly Correlated Electrons ,Condensed Matter - Mesoscale and Nanoscale Physics - Abstract
Transition metal compounds with kagome structure have been found to exhibit a variety of exotic structural, electronic, and magnetic orders. These orders are competing with energies very close to each other, resulting in complex phase transitions. Some of the phases are easily observable, such as the charge density wave (CDW) and the superconducting phase, while others are more challenging to identify and characterize. Here we present magneto-transport evidence of a new phase below ~35 K in the kagome topological metal CsV$_3$Sb$_5$ (CVS) thin flakes between the CDW and the superconducting transition temperatures. This phase is characterized by six-fold rotational symmetry in the in-plane magnetoresistance (MR) and is connected to the orbital current order in CVS. Furthermore, the phase is characterized by a large in-plane negative magnetoresistance, which suggests the existence of a three-dimensional, magnetic field-tunable orbital current ordered phase. Our results highlight the potential of magneto-transport to reveal the interactions between exotic quantum states of matter and to uncover the symmetry of such hidden phases.
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- 2024
19. StyleSeg V2: Towards Robust One-shot Segmentation of Brain Tissue via Optimization-free Registration Error Perception
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Wang, Zhiwei, Zeng, Xiaoyu, Wu, Chongwei, lv, Jinxin, Zhang, Xu, Fang, Wei, and Li, Qiang
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Computer Science - Computer Vision and Pattern Recognition - Abstract
One-shot segmentation of brain tissue requires training registration-segmentation (reg-seg) dual-model iteratively, where reg-model aims to provide pseudo masks of unlabeled images for seg-model by warping a carefully-labeled atlas. However, the imperfect reg-model induces image-mask misalignment, poisoning the seg-model subsequently. Recent StyleSeg bypasses this bottleneck by replacing the unlabeled images with their warped copies of atlas, but needs to borrow the diverse image patterns via style transformation. Here, we present StyleSeg V2, inherited from StyleSeg but granted the ability of perceiving the registration errors. The motivation is that good registration behaves in a mirrored fashion for mirrored images. Therefore, almost at no cost, StyleSeg V2 can have reg-model itself "speak out" incorrectly-aligned regions by simply mirroring (symmetrically flipping the brain) its input, and the registration errors are symmetric inconsistencies between the outputs of original and mirrored inputs. Consequently, StyleSeg V2 allows the seg-model to make use of correctly-aligned regions of unlabeled images and also enhances the fidelity of style-transformed warped atlas image by weighting the local transformation strength according to registration errors. The experimental results on three public datasets demonstrate that our proposed StyleSeg V2 outperforms other state-of-the-arts by considerable margins, and exceeds StyleSeg by increasing the average Dice by at least 2.4%., Comment: 10 pages, 11 figures, 2 tables
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- 2024
20. Nonvolatile optical control of interlayer stacking order in 1T-TaS2
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Liu, Junde, Liu, Pei, Yang, Liu, Lee, Sung-Hoon, Pan, Mojun, Chen, Famin, Huang, Jierui, Jiang, Bei, Hu, Mingzhe, Zhang, Yuchong, Xie, Zhaoyang, Wang, Gang, Guan, Mengxue, Jiang, Wei, Yang, Huaixin, Li, Jianqi, Yun, Chenxia, Wang, Zhiwei, Meng, Sheng, Yao, Yugui, Qian, Tian, and Shi, Xun
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Condensed Matter - Materials Science ,Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed Matter - Strongly Correlated Electrons - Abstract
Nonvolatile optical manipulation of material properties on demand is a highly sought-after feature in the advancement of future optoelectronic applications. While the discovery of such metastable transition in various materials holds good promise for achieving this goal, their practical implementation is still in the nascent stage. Here, we unravel the nature of the ultrafast laser-induced hidden state in 1T-TaS2 by systematically characterizing the electronic structure evolution throughout the reversible transition cycle. We identify it as a mixed-stacking state involving two similarly low-energy interlayer orders, which is manifested as the charge density wave phase disruption. Furthermore, our comparative experiments utilizing the single-pulse writing, pulse-train erasing and pulse-pair control explicitly reveal the distinct mechanism of the bidirectional transformations -- the ultrafast formation of the hidden state is initiated by a coherent phonon which triggers a competition of interlayer stacking orders, while its recovery to the initial state is governed by the progressive domain coarsening. Our work highlights the deterministic role of the competing interlayer orders in the nonvolatile phase transition in the layered material 1T-TaS2, and promises the coherent control of the phase transition and switching speed. More importantly, these results establish all-optical engineering of stacking orders in low-dimensional materials as a viable strategy for achieving desirable nonvolatile electronic devices.
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- 2024
21. Loss Jump During Loss Switch in Solving PDEs with Neural Networks
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Wang, Zhiwei, Zhang, Lulu, Zhang, Zhongwang, and Xu, Zhi-Qin John
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Computer Science - Machine Learning ,Mathematical Physics - Abstract
Using neural networks to solve partial differential equations (PDEs) is gaining popularity as an alternative approach in the scientific computing community. Neural networks can integrate different types of information into the loss function. These include observation data, governing equations, and variational forms, etc. These loss functions can be broadly categorized into two types: observation data loss directly constrains and measures the model output, while other loss functions indirectly model the performance of the network, which can be classified as model loss. However, this alternative approach lacks a thorough understanding of its underlying mechanisms, including theoretical foundations and rigorous characterization of various phenomena. This work focuses on investigating how different loss functions impact the training of neural networks for solving PDEs. We discover a stable loss-jump phenomenon: when switching the loss function from the data loss to the model loss, which includes different orders of derivative information, the neural network solution significantly deviates from the exact solution immediately. Further experiments reveal that this phenomenon arises from the different frequency preferences of neural networks under different loss functions. We theoretically analyze the frequency preference of neural networks under model loss. This loss-jump phenomenon provides a valuable perspective for examining the underlying mechanisms of neural networks in solving PDEs.
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- 2024
22. Direct observation of anisotropic Cooper pairing in kagome superconductor CsV3Sb5
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Mine, Akifumi, Zhong, Yigui, Liu, Jinjin, Suzuki, Takeshi, Najafzadeh, Sahand, Uchiyama, Takumi, Yin, Jia-Xin, Wu, Xianxin, Shi, Xun, Wang, Zhiwei, Yao, Yugui, and Okazaki, Kozo
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Condensed Matter - Superconductivity ,Condensed Matter - Materials Science - Abstract
In the recently discovered kagome superconductor AV3Sb5 (A = K, Rb, and Cs), the superconductivity is intertwined with an unconventional charge density wave order. Its pairing symmetry remains elusive owing to the lack of direct measurement of the superconducting gap in the momentum space. In this letter, utilizing laser-based ultra-high-resolution and low-temperature angle-resolved photoemission spectroscopy, we observe anisotropic Cooper pairing in kagome superconductor CsV3Sb5. We detect a highly anisotropic superconducting gap structure with an anisotropy over 80% and the gap maximum along the V-V bond direction on a Fermi surface originated from the 3d-orbital electrons of the V kagome lattice. It is in stark contrast to the isotropic superconducting gap structure on the other Fermi surface that is occupied by Sb 5p-orbital electrons. Our observation of the anisotropic Cooper pairing in pristine CsV3Sb5 is fundamental for understanding intertwined orders in the ground state of kagome superconductors.
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- 2024
23. MonoPCC: Photometric-invariant Cycle Constraint for Monocular Depth Estimation of Endoscopic Images
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Wang, Zhiwei, Zhou, Ying, He, Shiquan, Li, Ting, Huang, Fan, Ding, Qiang, Feng, Xinxia, Liu, Mei, and Li, Qiang
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Computer Science - Computer Vision and Pattern Recognition - Abstract
Photometric constraint is indispensable for self-supervised monocular depth estimation. It involves warping a source image onto a target view using estimated depth&pose, and then minimizing the difference between the warped and target images. However, the endoscopic built-in light causes significant brightness fluctuations, and thus makes the photometric constraint unreliable. Previous efforts only mitigate this relying on extra models to calibrate image brightness. In this paper, we propose MonoPCC to address the brightness inconsistency radically by reshaping the photometric constraint into a cycle form. Instead of only warping the source image, MonoPCC constructs a closed loop consisting of two opposite forward-backward warping paths: from target to source and then back to target. Thus, the target image finally receives an image cycle-warped from itself, which naturally makes the constraint invariant to brightness changes. Moreover, MonoPCC transplants the source image's phase-frequency into the intermediate warped image to avoid structure lost, and also stabilizes the training via an exponential moving average (EMA) strategy to avoid frequent changes in the forward warping. The comprehensive and extensive experimental results on four endoscopic datasets demonstrate that our proposed MonoPCC shows a great robustness to the brightness inconsistency, and exceeds other state-of-the-arts by reducing the absolute relative error by at least 7.27%, 9.38%, 9.90% and 3.17%, respectively., Comment: 11 pages, 10 figures
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- 2024
24. Local pairing versus bulk superconductivity intertwined by the charge density wave order in Cs(V$_{1-x}$Ta$_{x}$)$_{3}$Sb$_{5}$
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Li, Jinyulin, Li, Qing, Liu, Jinjin, Xiang, Ying, Yang, Huan, Wang, Zhiwei, Yao, Yugui, and Wen, Hai-Hu
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Condensed Matter - Superconductivity - Abstract
There is a common belief that superconductivity and charge density wave (CDW) order accommodate homogenously in real space but compete with each other for the effective density of states in momentum space in CDW superconductors. By measuring resistivity along the $c$-axis in Cs(V$_{1-x}$Ta$_{x}$)$_{3}$Sb$_{5}$, we observe strong superconducting fluctuation behavior coexisting with the CDW order in the pristine CsV$_{3}$Sb$_{5}$, and the fluctuation region becomes narrowed when the Ta doping suppresses the CDW order. The onset transition temperature barely changes with the Ta doping. Therefore, the bulk superconductivity may be established by a doping-independent local pairing, and it can be suppressed in some regions by the spatially variable CDW order along the $c$-axis. Our results violate the above-mentioned belief about CDW superconductors and demonstrate the intricate interaction between superconductivity and CDW order in this kagome superconductor., Comment: 9 pages, 5 figures
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- 2024
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25. Strong-coupling superconductivity and weak vortex pinning in Ta-doped CsV$_{3}$Sb$_{5}$ single crystals
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Li, Jinyulin, Xie, Wei, Liu, Jinjin, Li, Qing, Li, Xiang, Yang, Huan, Wang, Zhiwei, Yao, Yugui, and Wen, Hai-Hu
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Condensed Matter - Superconductivity - Abstract
By measuring magnetizations of pristine and Ta-doped CsV$_{3}$Sb$_{5}$ single crystals, we have carried out systematic studies on the lower critical field, critical current density, and equilibrium magnetization of this kagome system. The lower critical field has been investigated in the two typical samples, and the temperature dependent lower critical field obtained in Ta-doped sample can be fitted by using the model with two $s$-wave superconducting gaps yielding the larger gap of $2\Delta_{s1}/k_\mathrm{B}T_\mathrm{c}=7.9\;(\pm1.8)$. This indicates a strong-coupling feature of the V-based superconductors. The measured magnetization hysteresis loops allow us to calculate the critical current density, which shows a very weak bulk vortex pinning. The magnetization hysteresis loops measured in these two kinds of samples can be well described by a recently proposed generalized phenomenological model, which leads to the determination of many fundamental parameters for these superconductors. Our systematic results and detailed analysis conclude that this V-based kagome system has features of strong-coupling superconductivity, relatively large Ginzburg-Landau parameter and weak vortex coupling., Comment: 11 pages, 6 figures
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- 2024
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26. On the Range of a class of Complex Monge-Amp\`ere operators on compact Hermitian manifolds
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Li, Yinji, Wang, Zhiwei, and Zhou, Xiangyu
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Mathematics - Complex Variables - Abstract
Let $(X,\omega)$ be a compact Hermitian manifold of complex dimension $n$. Let $\beta$ be a smooth real closed $(1,1)$ form such that there exists a function $\rho \in \mbox{PSH}(X,\beta)\cap L^{\infty}(X)$. We study the range of the complex non-pluripolar Monge-Amp\`ere operator $\langle(\beta+dd^c\cdot)^n\rangle$ on weighted Monge-Amp\`ere energy classes on $X$. In particular, when $\rho$ is assumed to be continuous, we give a complete characterization of the range of the complex Monge-Amp\`ere operator on the class $\mathcal E(X,\beta)$, which is the class of all $\varphi \in \mbox{PSH}(X,\beta)$ with full Monge-Amp\`ere mass, i.e. $\int_X\langle (\beta+dd^c\varphi)^n\rangle=\int_X\beta^n$., Comment: Comments welcome!
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- 2024
27. MonoBox: Tightness-free Box-supervised Polyp Segmentation using Monotonicity Constraint
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Hu, Qiang, Yi, Zhenyu, Zhou, Ying, Li, Ting, Huang, Fan, Liu, Mei, Li, Qiang, and Wang, Zhiwei
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Computer Science - Computer Vision and Pattern Recognition - Abstract
We propose MonoBox, an innovative box-supervised segmentation method constrained by monotonicity to liberate its training from the user-unfriendly box-tightness assumption. In contrast to conventional box-supervised segmentation, where the box edges must precisely touch the target boundaries, MonoBox leverages imprecisely-annotated boxes to achieve robust pixel-wise segmentation. The 'linchpin' is that, within the noisy zones around box edges, MonoBox discards the traditional misguiding multiple-instance learning loss, and instead optimizes a carefully-designed objective, termed monotonicity constraint. Along directions transitioning from the foreground to background, this new constraint steers responses to adhere to a trend of monotonically decreasing values. Consequently, the originally unreliable learning within the noisy zones is transformed into a correct and effective monotonicity optimization. Moreover, an adaptive label correction is introduced, enabling MonoBox to enhance the tightness of box annotations using predicted masks from the previous epoch and dynamically shrink the noisy zones as training progresses. We verify MonoBox in the box-supervised segmentation task of polyps, where satisfying box-tightness is challenging due to the vague boundaries between the polyp and normal tissues. Experiments on both public synthetic and in-house real noisy datasets demonstrate that MonoBox exceeds other anti-noise state-of-the-arts by improving Dice by at least 5.5% and 3.3%, respectively. Codes are at https://github.com/Huster-Hq/MonoBox.
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- 2024
28. Conventional Superconductivity in the Doped Kagome Superconductor Cs(V0.86Ta0.14)3Sb5 from Vortex Lattice Studies
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Xie, Yaofeng, Chalus, Nathan, Wang, Zhiwei, Yao, Weiliang, Liu, Jinjin, Yao, Yugui, White, Jonathan S., DeBeer-Schmitt, Lisa M., Yin, Jia-Xin, Dai, Pengcheng, and Eskildsen, Morten Ring
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Condensed Matter - Superconductivity - Abstract
A hallmark of unconventional superconductors is their complex electronic phase diagrams where "intertwined orders" of charge-spin-lattice degrees of freedom compete and coexist as in copper oxides and iron pnictides. While the electronic phase diagram of kagome lattice superconductor such as CsV3Sb5 also exhibits complex behavior involving coexisting and competing charge density wave order and superconductivity, much is unclear about the microscopic origin of superconductivity. Here, we study the vortex lattice (VL) in superconducting state of Cs(V0.86Ta0.14)3Sb5, where the Ta-doping suppresses charge order and enhances superconductivity. Using small-angle neutron scattering, a strictly bulk probe, we show that the VL exhibits a strikingly conventional behavior. This includes a triangular VL with a period consistent with 2e-pairing, a field dependent scattering intensity that follows a London model, and a temperature dependence consistent with a uniform superconducting gap expected for s-wave pairing. These results suggest that optimal bulk superconductivity in Cs(V1-xTax)3Sb5 arises from a conventional Bardeen-Cooper-Schrieffer electron-lattice coupling, different from spin fluctuation mediated unconventional copper and iron based superconductors., Comment: Multiple revisions
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- 2024
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29. Orbital Magneto-Nonlinear Anomalous Hall Effect in Kagome Magnet Fe$_3$Sn$_2$
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Wang, Lujunyu, Zhu, Jiaojiao, Chen, Haiyun, Wang, Hui, Liu, Jinjin, Huang, Yue-Xin, Jiang, Bingyan, Zhao, Jiaji, Shi, Hengjie, Tian, Guang, Wang, Haoyu, Yao, Yugui, Yu, Dapeng, Wang, Zhiwei, Xiao, Cong, Yang, Shengyuan A., and Wu, Xiaosong
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Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed Matter - Strongly Correlated Electrons - Abstract
It has been theoretically predicted that perturbation of the Berry curvature by electromagnetic fields gives rise to intrinsic nonlinear anomalous Hall effects that are independent of scattering. Two types of nonlinear anomalous Hall effects are expected. The electric nonlinear Hall effect has recently begun to receive attention, while very few studies are concerned with the magneto-nonlinear Hall effect. Here, we combine experiment and first-principles calculations to show that the kagome ferromagnet Fe$_3$Sn$_2$ displays such a magneto-nonlinear Hall effect. By systematic field angular and temperature-dependent transport measurements, we unambiguously identify a large anomalous Hall current that is linear in both applied in-plane electric and magnetic fields, utilizing a unique in-plane configuration. We clarify its dominant orbital origin and connect it to the magneto-nonlinear Hall effect. The effect is governed by the intrinsic quantum geometric properties of Bloch electrons. Our results demonstrate the significance of the quantum geometry of electron wave functions from the orbital degree of freedom and open up a new direction in Hall transport effects., Comment: 18 pages, 4 figures, featured in Physics: Viewpoint and Editors' suggestions
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- 2024
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30. Stealthy Adversarial Attacks on Stochastic Multi-Armed Bandits
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Wang, Zhiwei, Wang, Huazheng, and Wang, Hongning
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Computer Science - Machine Learning ,Computer Science - Cryptography and Security - Abstract
Adversarial attacks against stochastic multi-armed bandit (MAB) algorithms have been extensively studied in the literature. In this work, we focus on reward poisoning attacks and find most existing attacks can be easily detected by our proposed detection method based on the test of homogeneity, due to their aggressive nature in reward manipulations. This motivates us to study the notion of stealthy attack against stochastic MABs and investigate the resulting attackability. Our analysis shows that against two popularly employed MAB algorithms, UCB1 and $\epsilon$-greedy, the success of a stealthy attack depends on the environmental conditions and the realized reward of the arm pulled in the first round. We also analyze the situation for general MAB algorithms equipped with our attack detection method and find that it is possible to have a stealthy attack that almost always succeeds. This brings new insights into the security risks of MAB algorithms.
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- 2024
31. LiRank: Industrial Large Scale Ranking Models at LinkedIn
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Borisyuk, Fedor, Zhou, Mingzhou, Song, Qingquan, Zhu, Siyu, Tiwana, Birjodh, Parameswaran, Ganesh, Dangi, Siddharth, Hertel, Lars, Xiao, Qiang, Hou, Xiaochen, Ouyang, Yunbo, Gupta, Aman, Singh, Sheallika, Liu, Dan, Cheng, Hailing, Le, Lei, Hung, Jonathan, Keerthi, Sathiya, Wang, Ruoyan, Zhang, Fengyu, Kothari, Mohit, Zhu, Chen, Sun, Daqi, Dai, Yun, Luan, Xun, Zhu, Sirou, Wang, Zhiwei, Daftary, Neil, Shen, Qianqi, Jiang, Chengming, Wei, Haichao, Varshney, Maneesh, Ghoting, Amol, and Ghosh, Souvik
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Computer Science - Machine Learning ,Computer Science - Artificial Intelligence ,Computer Science - Information Retrieval ,H.3.3 - Abstract
We present LiRank, a large-scale ranking framework at LinkedIn that brings to production state-of-the-art modeling architectures and optimization methods. We unveil several modeling improvements, including Residual DCN, which adds attention and residual connections to the famous DCNv2 architecture. We share insights into combining and tuning SOTA architectures to create a unified model, including Dense Gating, Transformers and Residual DCN. We also propose novel techniques for calibration and describe how we productionalized deep learning based explore/exploit methods. To enable effective, production-grade serving of large ranking models, we detail how to train and compress models using quantization and vocabulary compression. We provide details about the deployment setup for large-scale use cases of Feed ranking, Jobs Recommendations, and Ads click-through rate (CTR) prediction. We summarize our learnings from various A/B tests by elucidating the most effective technical approaches. These ideas have contributed to relative metrics improvements across the board at LinkedIn: +0.5% member sessions in the Feed, +1.76% qualified job applications for Jobs search and recommendations, and +4.3% for Ads CTR. We hope this work can provide practical insights and solutions for practitioners interested in leveraging large-scale deep ranking systems.
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- 2024
32. Tunable vortex bound states in multiband CsV3Sb5-derived kagome superconductors
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Huang, Zihao, Han, Xianghe, Zhao, Zhen, Liu, Jinjin, Li, Pengfei, Tan, Hengxin, Wang, Zhiwei, Yao, Yugui, Yang, Haitao, Yan, Binghai, Jiang, Kun, Hu, Jiangping, Wang, Ziqiang, Chen, Hui, and Gao, Hong-Jun
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Condensed Matter - Superconductivity - Abstract
Vortices and bound states offer an effective means of comprehending the electronic properties of superconductors. Recently, surface dependent vortex core states have been observed in the newly discovered kagome superconductors CsV3Sb5. Although the spatial distribution of the sharp zero energy conductance peak appears similar to Majorana bound states arising from the superconducting Dirac surface states, its origin remains elusive. In this study, we present observations of tunable vortex bound states (VBSs) in two chemically doped kagome superconductors Cs(V1-xTrx)3Sb5 (Tr=Ta or Ti), using low temperature scanning tunneling microscopy/spectroscopy. The CsV3Sb5-derived kagome superconductors exhibit full gap pairing superconductivity accompanied by the absence of long range charge orders, in contrast to pristine CsV3Sb5. Zero energy conductance maps demonstrate a field-driven continuous reorientation transition of the vortex lattice, suggesting multiband superconductivity. The Ta doped CsV3Sb5 displays the conventional cross shaped spatial evolution of Caroli de Gennes Matricon bound states, while the Ti doped CsV3Sb5 exhibits a sharp, non split zero bias conductance peak (ZBCP) that persists over a long distance across the vortex. The spatial evolution of the non split ZBCP is robust against surface effects and external magnetic field but is related to the doping concentrations. Our study reveals the tunable VBSs in multiband chemically doped CsV3Sb5 system and offers fresh insights into previously reported Y shaped ZBCP in a non quantum limit condition at the surface of kagome superconductor., Comment: accepted by Science Bulletin DOI:10.1016/j.scib.2024.01.036
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- 2024
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33. Discovery of a Topological Charge Density Wave
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Litskevich, Maksim, Hossain, Md Shafayat, Zhang, Songbo, Cheng, Zi-Jia, Guin, Satya N., Kumar, Nitesh, Shekhar, Chandra, Wang, Zhiwei, Li, Yongkai, Chang, Guoqing, Yin, Jia-Xin, Zhang, Qi, Cheng, Guangming, Jiang, Yu-Xiao, Cochran, Tyler A., Shumiya, Nana, Yang, Xian P., Multer, Daniel, Liu, Xiaoxiong, Yao, Nan, Yao, Yugui, Felser, Claudia, Neupert, Titus, and Hasan, M. Zahid
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Condensed Matter - Strongly Correlated Electrons ,Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed Matter - Materials Science ,Condensed Matter - Other Condensed Matter ,Physics - Applied Physics - Abstract
Charge density waves (CDWs) appear in numerous condensed matter platforms, ranging from high-Tc superconductors to quantum Hall systems. Despite such ubiquity, there has been a lack of direct experimental study on boundary states that can uniquely stem from the charge order. Here, using scanning tunneling microscopy, we directly visualize the bulk and boundary phenomenology of CDW in a topological material, Ta2Se8I. Below the transition temperature (TCDW = 260 K), tunneling spectra on an atomically resolved lattice reveal a large insulating gap in the bulk and on the surface, exceeding 500 meV, surpassing predictions from standard weakly-coupled mean-field theory. Spectroscopic imaging confirms the presence of CDW, with LDOS maxima at the conduction band corresponding to the LDOS minima at the valence band, thus revealing a {\pi} phase difference in the respective CDW order. Concomitantly, at a monolayer step edge, we detect an in-gap boundary mode with modulations along the edge that match the CDW wavevector along the edge. Intriguingly, the phase of the edge state modulation shifts by {\pi} within the charge order gap, connecting the fully gapped bulk (and surface) conduction and valence bands via a smooth energy-phase relation. This bears similarity to the topological spectral flow of edge modes, where the boundary modes bridge the gapped bulk modes in energy and momentum magnitude but in Ta2Se8I, the connectivity distinctly occurs in energy and momentum phase. Notably, our temperature-dependent measurements indicate a vanishing of the insulating gap and the in-gap edge state above TCDW, suggesting their direct relation to CDW. The theoretical analysis also indicates that the observed boundary mode is topological and linked to CDW., Comment: Nature Physics (2024); in press
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- 2024
34. Learning-Based Baseline Method for Efficient Determination of Overlapping Image Pairs and Its Application On both Offline and Online SfM
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Wang, Xin, Wang, Zhiwei, Xu, Yiwei, and Zhan, Zongqian
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- 2024
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35. LQ optimal control of uncertain fractional differential systems
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Wang, Zhiwei and Zhu, Yuanguo
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- 2024
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36. Research on the online evaluation of the straightness error of hydrostatic guideways based on deep learning
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Wang, Zhiwei, Jia, Yanhao, Fu, Penghao, Li, Haiyin, Song, Li, Yang, Bingqing, Zhang, Lijun, Yuan, Liang, and Shi, Kan
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- 2024
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37. Effects of Pressure Holding Time on Magnetic Properties and Corrosion Resistance of Hot-Deformed NdFeB Magnets
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Li, Xiaoqiang, Ni, Junjie, Wang, Zhiwei, Song, Bo, Wang, Changzheng, and Cui, Xigui
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- 2024
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38. Chiral kagome superconductivity modulations with residual Fermi arcs
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Deng, Hanbin, Qin, Hailang, Liu, Guowei, Yang, Tianyu, Fu, Ruiqing, Zhang, Zhongyi, Wu, Xianxin, Wang, Zhiwei, Shi, Youguo, Liu, Jinjin, Liu, Hongxiong, Yan, Xiao-Yu, Song, Wei, Xu, Xitong, Zhao, Yuanyuan, Yi, Mingsheng, Xu, Gang, Hohmann, Hendrik, Holbæk, Sofie Castro, Dürrnagel, Matteo, Zhou, Sen, Chang, Guoqing, Yao, Yugui, Wang, Qianghua, Guguchia, Zurab, Neupert, Titus, Thomale, Ronny, Fischer, Mark H., and Yin, Jia-Xin
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- 2024
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39. Boundary modes of a charge density wave state in a topological material
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Litskevich, Maksim, Hossain, Md Shafayat, Zhang, Song-Bo, Cheng, Zi-Jia, Guin, Satya N., Kumar, Nitesh, Shekhar, Chandra, Wang, Zhiwei, Li, Yongkai, Chang, Guoqing, Yin, Jia-Xin, Zhang, Qi, Cheng, Guangming, Cochran, Tyler A., Shumiya, Nana, Jiang, Yu-Xiao, Yang, Xian P., Multer, Daniel, Liu, Xiaoxiong, Yao, Nan, Yao, Yugui, Felser, Claudia, Neupert, Titus, and Hasan, M. Zahid
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- 2024
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40. Two-step continuous alkali pretreatment for fractionation of the carbohydrates from bamboo and cotton stalk
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Mou, Hongyan, Tang, Lv, Liu, Yibei, Huang, Jin, Feng, Lu, Wu, Xiao, and Wang, Zhiwei
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- 2024
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41. Discovery of a topological exciton insulator with tunable momentum order
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Hossain, Md Shafayat, Cochran, Tyler A., Jiang, Yu-Xiao, Zhang, Songbo, Wu, Huangyu, Liu, Xiaoxiong, Zheng, Xiquan, Kim, Byunghoon, Cheng, Guangming, Zhang, Qi, Litskevich, Maksim, Zhang, Junyi, Cheng, Zi-Jia, Liu, Jinjin, Yin, Jia-Xin, Yang, Xian P., Denlinger, Jonathan, Tallarida, Massimo, Dai, Ji, Vescovo, Elio, Rajapitamahuni, Anil, Miao, Hu, Yao, Nan, Peng, Yingying, Yao, Yugui, Wang, Zhiwei, Balicas, Luis, Neupert, Titus, and Hasan, M. Zahid
- Subjects
Condensed Matter - Strongly Correlated Electrons ,Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed Matter - Materials Science ,Quantum Physics - Abstract
Topology and correlations are fundamental concepts in modern physics, but their simultaneous occurrence within a single quantum phase is exceptionally rare. In this study, we present the discovery of such a phase of matter in Ta2Pd3Te5, a semimetal where the Coulomb interaction between electrons and holes leads to the spontaneous formation of excitonic bound states below T=100 K. Our spectroscopy unveils the development of an insulating gap stemming from the condensation of these excitons, thus giving rise to a highly sought-after correlated quantum phase known as the excitonic insulator. Remarkably, our scanning tunneling microscopy measurements reveal the presence of gapless boundary modes in the excitonic insulator state. Their magnetic field response and our theoretical calculations suggest a topological origin of these modes, rendering Ta2Pd3Te5 as the first experimentally identified topological excitonic insulator in a three-dimensional material not masked by any structural phase transition. Furthermore, our study uncovers a secondary excitonic instability below T=5 K, which differs from the primary one in having finite momentum. We observe unprecedented tunability of its wavevector by an external magnetic field. These findings unlock a frontier in the study of novel correlated topological phases of matter and their tunability.
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- 2023
42. SegRap2023: A Benchmark of Organs-at-Risk and Gross Tumor Volume Segmentation for Radiotherapy Planning of Nasopharyngeal Carcinoma
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Luo, Xiangde, Fu, Jia, Zhong, Yunxin, Liu, Shuolin, Han, Bing, Astaraki, Mehdi, Bendazzoli, Simone, Toma-Dasu, Iuliana, Ye, Yiwen, Chen, Ziyang, Xia, Yong, Su, Yanzhou, Ye, Jin, He, Junjun, Xing, Zhaohu, Wang, Hongqiu, Zhu, Lei, Yang, Kaixiang, Fang, Xin, Wang, Zhiwei, Lee, Chan Woong, Park, Sang Joon, Chun, Jaehee, Ulrich, Constantin, Maier-Hein, Klaus H., Ndipenoch, Nchongmaje, Miron, Alina, Li, Yongmin, Zhang, Yimeng, Chen, Yu, Bai, Lu, Huang, Jinlong, An, Chengyang, Wang, Lisheng, Huang, Kaiwen, Gu, Yunqi, Zhou, Tao, Zhou, Mu, Zhang, Shichuan, Liao, Wenjun, Wang, Guotai, and Zhang, Shaoting
- Subjects
Electrical Engineering and Systems Science - Image and Video Processing ,Computer Science - Computer Vision and Pattern Recognition - Abstract
Radiation therapy is a primary and effective NasoPharyngeal Carcinoma (NPC) treatment strategy. The precise delineation of Gross Tumor Volumes (GTVs) and Organs-At-Risk (OARs) is crucial in radiation treatment, directly impacting patient prognosis. Previously, the delineation of GTVs and OARs was performed by experienced radiation oncologists. Recently, deep learning has achieved promising results in many medical image segmentation tasks. However, for NPC OARs and GTVs segmentation, few public datasets are available for model development and evaluation. To alleviate this problem, the SegRap2023 challenge was organized in conjunction with MICCAI2023 and presented a large-scale benchmark for OAR and GTV segmentation with 400 Computed Tomography (CT) scans from 200 NPC patients, each with a pair of pre-aligned non-contrast and contrast-enhanced CT scans. The challenge's goal was to segment 45 OARs and 2 GTVs from the paired CT scans. In this paper, we detail the challenge and analyze the solutions of all participants. The average Dice similarity coefficient scores for all submissions ranged from 76.68\% to 86.70\%, and 70.42\% to 73.44\% for OARs and GTVs, respectively. We conclude that the segmentation of large-size OARs is well-addressed, and more efforts are needed for GTVs and small-size or thin-structure OARs. The benchmark will remain publicly available here: https://segrap2023.grand-challenge.org, Comment: A challenge report of SegRap2023 (organized in conjunction with MICCAI2023)
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- 2023
43. Transport response of topological hinge modes in $\alpha$-Bi$_4$Br$_4$
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Hossain, Md Shafayat, Zhang, Qi, Wang, Zhiwei, Dhale, Nikhil, Liu, Wenhao, Litskevich, Maksim, Casas, Brian, Shumiya, Nana, Yin, Jia-Xin, Cochran, Tyler A., Li, Yongkai, Jiang, Yu-Xiao, Yang, Ying, Cheng, Guangming, Cheng, Zi-Jia, Yang, Xian P., Yao, Nan, Neupert, Titus, Balicas, Luis, Yao, Yugui, Lv, Bing, and Hasan, M. Zahid
- Subjects
Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed Matter - Materials Science ,Physics - Applied Physics ,Quantum Physics - Abstract
Electronic topological phases are renowned for their unique properties, where conducting surface states exist on the boundary of an insulating three-dimensional bulk. While the transport response of the surface states has been extensively studied, the response of the topological hinge modes remains elusive. Here, we investigate a layered topological insulator $\alpha$-Bi$_4$Br$_4$, and provide the first evidence for quantum transport in gapless topological hinge states existing within the insulating bulk and surface energy gaps. Our magnetoresistance measurements reveal pronounced h/e periodic (where h denotes Planck's constant and e represents the electron charge) Aharonov-Bohm oscillation. The observed periodicity, which directly reflects the enclosed area of phase-coherent electron propagation, matches the area enclosed by the sample hinges, providing compelling evidence for the quantum interference of electrons circumnavigating around the hinges. Notably, the h/e oscillations evolve as a function of magnetic field orientation, following the interference paths along the hinge modes that are allowed by topology and symmetry, and in agreement with the locations of the hinge modes according to our scanning tunneling microscopy images. Remarkably, this demonstration of quantum transport in a topological insulator can be achieved using a flake geometry and we show that it remains robust even at elevated temperatures. Our findings collectively reveal the quantum transport response of topological hinge modes with both topological nature and quantum coherence, which can be directly applied to the development of efficient quantum electronic devices., Comment: Nature Physics, in press (2023)
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- 2023
44. Pressure-induced Superconductivity and Topological Quantum Phase Transitions in the Topological Semimetal ZrTe2
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Zhu, Shihao, Wu, Juefei, Zhu, Peng, Pei, Cuiying, Wang, Qi, Jia, Donghan, Wang, Xinyu, Zhao, Yi, Gao, Lingling, Li, Changhua, Cao, Weizheng, Zhang, Mingxin, Zhang, Lili, Li, Mingtao, Gou, Huiyang, Yang, Wenge, Sun, Jian, Chen, Yulin, Wang, Zhiwei, Yao, Yugui, and Qi, Yanpeng
- Subjects
Condensed Matter - Superconductivity ,Condensed Matter - Materials Science - Abstract
Topological transition metal dichalcogenides (TMDCs) have attracted much attention due to its potential applications in spintronics and quantum computations. In this work, we systematically investigate the structural and electronic properties of topological TMDCs candidate ZrTe2 under high pressure. A pressure-induced Lifshitz transition is evidenced by the change of charge carrier type as well as the Fermi surface. Superconductivity was observed at around 8.3 GPa without structural phase transition. A typical dome-shape phase diagram is obtained with the maximum Tc of 5.6 K for ZrTe2. Furthermore, our theoretical calculations suggest the presence of multiple pressure-induced topological quantum phase transitions, which coexists with emergence of superconductivity. The results demonstrate that ZrTe2 with nontrivial topology of electronic states display new ground states upon compression., Comment: Accepted for publication in Advanced Science 2023
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- 2023
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45. Pressure-induced Superconductivity and Structure Phase Transition in SnAs-based Zintl Compound SrSn2As2
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Cao, Weizheng, Wu, Juefei, Li, Yongkai, Pei, Cuiying, Wang, Qi, Zhao, Yi, Li, Changhua, Zhu, Shihao, Zhang, Mingxin, Zhang, Lili, Chen, Yulin, Wang, Zhiwei, Yao, Yugui, and Qi, Yanpeng
- Subjects
Condensed Matter - Superconductivity ,Condensed Matter - Materials Science - Abstract
Layered SnAs-based Zintl compounds exhibit a distinctive electronic structure, igniting extensive research efforts in areas of superconductivity, topological insulators and quantum magnetism. In this paper, we systematically investigate the crystal structures and electronic properties of the Zintl compound SrSn2As2 under high-pressure. At approximately 20.8 GPa, pressure-induced superconductivity is observed in SrSn2As2 with a characteristic dome-like evolution of Tc. Theoretical calculations together with high pressure synchrotron X-ray diffraction and Raman spectroscopy have identified that SrSn2As2 undergoes a structural transformation from a trigonal to a monoclinic structure. Beyond 28.3 GPa, the superconducting transition temperature is suppressed due to a reduction of the density of state at the Fermi level. The discovery of pressure-induced superconductivity, accompanied by structural transitions in SrSn2As2, greatly expands the physical properties of layered SnAs-based compounds and provides a new ground states upon compression., Comment: 15 pages, 6 figures. arXiv admin note: text overlap with arXiv:2307.15629
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- 2023
46. IBoxCLA: Towards Robust Box-supervised Segmentation of Polyp via Improved Box-dice and Contrastive Latent-anchors
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Wang, Zhiwei, Hu, Qiang, Shi, Hongkuan, He, Li, He, Man, Dai, Wenxuan, Tian, Yinjiao, Yang, Xin, Liu, Mei, and Li, Qiang
- Subjects
Computer Science - Computer Vision and Pattern Recognition - Abstract
Box-supervised polyp segmentation attracts increasing attention for its cost-effective potential. Existing solutions often rely on learning-free methods or pretrained models to laboriously generate pseudo masks, triggering Dice constraint subsequently. In this paper, we found that a model guided by the simplest box-filled masks can accurately predict polyp locations/sizes, but suffers from shape collapsing. In response, we propose two innovative learning fashions, Improved Box-dice (IBox) and Contrastive Latent-Anchors (CLA), and combine them to train a robust box-supervised model IBoxCLA. The core idea behind IBoxCLA is to decouple the learning of location/size and shape, allowing for focused constraints on each of them. Specifically, IBox transforms the segmentation map into a proxy map using shape decoupling and confusion-region swapping sequentially. Within the proxy map, shapes are disentangled, while locations/sizes are encoded as box-like responses. By constraining the proxy map instead of the raw prediction, the box-filled mask can well supervise IBoxCLA without misleading its shape learning. Furthermore, CLA contributes to shape learning by generating two types of latent anchors, which are learned and updated using momentum and segmented polyps to steadily represent polyp and background features. The latent anchors facilitate IBoxCLA to capture discriminative features within and outside boxes in a contrastive manner, yielding clearer boundaries. We benchmark IBoxCLA on five public polyp datasets. The experimental results demonstrate the competitive performance of IBoxCLA compared to recent fully-supervised polyp segmentation methods, and its superiority over other box-supervised state-of-the-arts with a relative increase of overall mDice and mIoU by at least 6.5% and 7.5%, respectively.
- Published
- 2023
47. Reducing the contour error of leading and trailing edge through feedrate scheduling in 5-axis machining of blisk
- Author
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Wang, Zhiwei, Lin, Xiaojun, Shan, Chenwei, and Tian, Heng
- Published
- 2024
- Full Text
- View/download PDF
48. Delivery of exogenous miR-19b by Wharton’s Jelly Mesenchymal Stem Cells attenuates transplanted kidney ischemia/reperfusion injury by regulating cellular metabolism
- Author
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Wu, Xiaoqiang, Wu, Xuan, Wang, Zhiwei, Tian, Xiangyong, Zhang, Chan, Cao, Guanghui, Gu, Yue, and Yan, Tianzhong
- Published
- 2024
- Full Text
- View/download PDF
49. Superconducting diode effect and interference patterns in kagome CsV3Sb5
- Author
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Le, Tian, Pan, Zhiming, Xu, Zhuokai, Liu, Jinjin, Wang, Jialu, Lou, Zhefeng, Yang, Xiaohui, Wang, Zhiwei, Yao, Yugui, Wu, Congjun, and Lin, Xiao
- Published
- 2024
- Full Text
- View/download PDF
50. Strand-preferred base editing of organellar and nuclear genomes using CyDENT
- Author
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Hu, Jiacheng, Sun, Yu, Li, Boshu, Liu, Zhen, Wang, Zhiwei, Gao, Qiang, Guo, Mengyue, Liu, Guanwen, Zhao, Kevin Tianmeng, and Gao, Caixia
- Published
- 2024
- Full Text
- View/download PDF
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