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Consumer Electronics and Computer Engineering (ICCECE), 2021 IEEE International Conference on

作者： Yongkang Wang Yang Liu Zhiguang Chen School of Computer Science and Engineering Sun Yat-sen University Guangzhou China State Key Laboratory of High-Performance Computing Institute for Quantum Information College of Computer National University of Defense Technology Changsha China

With the development of emerging technologies such as cloud computing and large AI models (such as LLM), many applications have placed higher demands on the intensive read and write processing of massive data. Addressing the limitations of traditional file systems, we propose PancakeFS, an LSM-Tree-based file system. Leveraging the write-friendly characteristics of LSM-Tree, PancakeFS exhibits efficient write performance. We improve read performance through the design of an inode allocation algorithm based on subtree partitioning and optimization of the disk layout for hot data reconstruction. Our experimental results demonstrate that PancakeFS outperforms Ext4 and TableFS in terms of both read and write performance.

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Developing a proxy application for an industrial unstructured CFD software: preliminary results

Developing a proxy application for an industrial unstructure...

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International Conference on Parallel and Distributed Systems (ICPADS)

作者： Qingsong Wang Chuanfu Xu Jian Zhang Liang Deng Zhe Dai Haozhong Qiu Weixi Dai Yongzhen Lin Yue Ding Yonggang Che Institute for Quantum Information & State Key Laboratory of High Performance Computing National University of Defense Technology Changsha China China Aerodynamic Research and Development Center Mianyang China

As programming models and architectures evolve in the exa-scale era, porting large-scale HPC applications are becoming increasingly difficult and expensive. In HPC community, mini-apps are often developed to mimic real-world applications, and it offers an easy way to benchmark new HPC platforms. In this paper, we design and implement a mini-app MiniFS as a proxy for an industry-level unstructured Computational Fluid Dynamics (CFD) software FlowStar. The main purpose of MiniFS is to evaluate different shared memory approaches on emerging multi/many-core architectures, because data conflicts and data dependencies in unstructured CFD pose tough challenges for shared memory parallelization. Results show that our mini-app can represent the performance characteristic of the original application. However, the existing approaches are unscalable on modern multi/many-cores. It is imperative to develop novel scalable shared memory approaches for unstructured CFD.

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Magnetic field-induced non-linear transport in HfTe5

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National Science Review 2022年第10期9卷 98-104页

作者： Cheng Zhang Jinshan Yang Zhongbo Yan Xiang Yuan Yanwen Liu Minhao Zhao Alexey Suslov Jinglei Zhang Li Pi Zhong Wang Faxian Xiu State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing Fudan University State Key Laboratory of Surface Physics and Department of Physics Fudan University Zhangjiang Fudan International Innovation Center Fudan University State Key Laboratory of High-Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences School of Physics Sun Yat-Sen University State Key Laboratory of Precision Spectroscopy East China Normal University National High Magnetic Field Laboratory Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions High Magnetic Field Laboratory of the Chinese Academy of Sciences Institute for Advanced Study Tsinghua University Collaborative Innovation Center of Quantum Matter Shanghai Qi Zhi Institute Shanghai Research Center for Quantum Sciences

The interplay of electron correlations and topological phases gives rise to various exotic phenomena including fractionalization,excitonic instability and axionic *** discovered transition-metal pentatellurides can reach the ultra-quantum limit in low magnetic fields and serve as good candidates for achieving such a ***,we report evidence of density wave and metal-insulator transition in HfTe5induced by intense magnetic *** the non-linear transport technique,we detect a distinct non-linear conduction behavior in the longitudinal resistivity within the a-c plane,corresponding to the formation of a density wave induced by magnetic *** high fields,the onset of non-linear conduction in the Hall resistivity indicates an impurity-pinned magnetic freeze-out as the possible origin of the insulating *** frozen electrons can be gradually reactivated into mobile states above a threshold of electric *** experimental evidence calls for further investigation into the underlying mechanism of the bulk quantum Hall effect and field-induced phase transitions in pentatellurides.

关键词： topological state quantum transport electron correlation density wave non-linear transport

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Optimized circuits for windowed modular arithmetic with applications to quantum attacks against RSA

arXiv

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arXiv 2025年

作者： Luongo, Alessandro Narasimhachar, Varun Sireesh, Adithya Centre for Quantum Technologies National University of Singapore Singapore Inveriant Pte. Ltd. Singapore Institute of High Performance Computing Agency for Science Technology and Research Singapore School of Informatics University of Edinburgh Scotland United Kingdom

Windowed arithmetic [Gidney, 2019] is a technique for reducing the cost of quantum arithmetic circuits with space–time tradeoffs using memory queries to precomputed tables. It can reduce the asymptotic cost of modular exponentiation from O(n3) to O(n3/log2 n) operations, resulting in the current state-of-the-art compilations of quantum attacks against modern cryptography. In this work we introduce four optimizations to windowed modular exponentiation. We (1) show how the cost of unlookups can be reduced by 66% asymptotically in the number of bits, (2) illustrate how certain addresses can be bypassed, reducing both circuit depth and the overall lookup cost, (3) demonstrate that multiple lookup–addition operations can be merged into a single, larger lookup at the start of the modular exponentiation circuit, and (4) reduce the depth of the unary conversion for unlookups. On a logical level, this leads to a 3% improvement in Toffoli count and Toffoli depth for modular exponentiation circuits relevant to cryptographic applications. This translates to some improvements on [Gidney and Ekerå, 2021]’s factoring algorithm: for a given number of physical qubits, our improvements show a reduction in the expected runtime from 2% to 6% for factoring RSA-2048 *** Codes 81P68, 68Q09, 68Q12 © 2025, CC0.

关键词： Table lookup

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Cryogenic Control and Readout Integrated Circuits for Solid-State quantum computing

arXiv

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arXiv 2024年

作者： Lei, Lingxiao Huang, Heng Chen, Pingxing Deng, Mingtang Institute for Quantum Information State Key Laboratory of High Performance Computing College of Computer Science and Technology National University of Defense Technology Changsha410073 China Institute for Quantum Science and Technology College of Sciences National University of Defense Technology Changsha410073 China

In the pursuit of quantum computing, solid-state quantum systems, particularly superconducting ones, have made remarkable advancements over the past two decades. However, achieving fault-tolerant quantum computing for next-generation applications necessitates the integration of several million qubits, which presents significant challenges in terms of interconnection complexity and latency that are currently unsolvable with state-of-the-art room-temperature control and readout electronics. Recently, cryogenic integrated circuits (ICs), including CMOS radio-frequency ICs and rapid-single-flux-quantum-logic ICs, have emerged as potential alternatives to room-temperature electronics. Unlike their room-temperature counterparts, these ICs are deployed within cryostats to enhance scalability by reducing the number and length of transmission lines. Additionally, operating at cryogenic temperatures can suppress electronic noise and improve qubit control fidelity. However, for CMOS ICs specifically, circuit design uncertainties arise due to a lack of reliable models for cryogenic field effect transistors as well as issues related to severe fickle noises and power dissipation at cryogenic temperatures. This paper provides a comprehensive review of recent research on both types of cryogenic control and readout ICs but primarily focuses on the more mature CMOS technology. The discussion encompasses principles underlying control and readout techniques employed in cryogenic CMOS ICs along with their architectural designs;characterization and modeling approaches for field effect transistors under cryogenic conditions;as well as fundamental concepts pertaining to rapid single flux quantum circuits. In conclusion, while prototypes of cryogenic ICs have been successfully fabricated recently, further studies are still necessary;we believe that rapid single-flux-quantum-based or hybrid ICs featuring enhanced digital components may represent the future direction in this emerging area. ©

关键词： CMOS integrated circuits

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Simultaneously Learning Syntactic Dependency and Semantics Reasonability for Relation Extraction

Simultaneously Learning Syntactic Dependency and Semantics R...

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International Conference on Image, Vision and Intelligent Systems, ICIVIS 2021

作者： Wang, Xin Yin, Nan Zhang, Xiang Bai, Xinyi Luo, Zhigang College of Computer National University of Defense Technology Changsha China Institute for Quantum and State Key Laboratory of High Performance Computing National University of Defense Technology Changsha China Science and Technology on Parallel and Distributed Laboratory National University of Defense Technology Changsha China

ISBN: (纸本)9789811669620

Relation extraction as an important Natural Language Processing (NLP) task is to identify relations between named entities in text. Recently, graph convolutional networks over dependency trees have been widely used to capture syntactic features and achieved attractive performance. However, most existing dependency-based approaches ignore the positive influence of the words outside the dependency trees, sometimes conveying rich and useful information on relation extraction. In this paper, we propose a novel model, Entity-aware Self-attention Contextualized GCN (ESC-GCN), which efficiently incorporates syntactic structure of input sentences and semantic context of sequences. To be specific, relative position self-attention obtains the overall semantic pairwise correlation related to word position, and contextualized graph convolutional networks capture rich intra-sentence dependencies between words by adequately pruning operations. In this way, our proposed model not only reduces the noisy impact from dependency trees but also obtains easily-ignored entity-related semantic representation. Extensive experiments demonstrate that our model achieves encouraging performance. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Semantics

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A Cross-domain Radar Emitter Recognition Method with Few-shot Learning

A Cross-domain Radar Emitter Recognition Method with Few-sho...

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Computer Engineering and Intelligent Communications (ISCEIC), International Symposium on

作者： Yixian Luo Tianrui Liu Xueqiong Li Hengzhu Liu Institute for Quantum Information & State Key Laboratory of High Performance Computing National University of Defense Technology Changsha China College of Computer National University of Defense Technology Changsha China

In many realistic scenarios, it is necessary but challenging to acquire a large number of annotated radar emitter samples for training a recognition model. This study proposes a cross-domain radar emitter recognition method with few-shot learning, which introduces model-agnostic meta-learning (MAML) to recognize radar emitter and improves it to adapt to various types of radar emitter in different domains without spending a lot of time and data to retrain the model. This method can learn an ideal initialization parameter with a few source domain samples, and then initialize with this parameter on a completely different target domain. It can obtain good generalization effect by fine-tuning with fewer samples, so as to realize cross-domain recognition of radar emitter. Simulation results show that the accuracy of the proposed method can reach more than 90% in high-noise target domains with completely different data distribution from the source domain, which shows its superiority in recognition performance and sample size compared with other radar emitter recognition methods.

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quantum-Inspired VCSEL-based Optical Parallel Feedback System for Large-Scale Combinatorial Optimization

Quantum-Inspired VCSEL-based Optical Parallel Feedback Syste...

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OptoElectronics and Communications Conference, OECC

作者： Soon Thor Lim Dewen Zhang Zifeng Yuan Thanh Xuan Hoang Ching Eng Png Aaron Danner Electronics and Photonics Nano & Quantum Photonics/AI Institute of High Performance Computing (IHPC) Agency for Science Technology and Research (A⋆STAR) Singapore Singapore Dept. of Electrical and Computer Engineering National University of Singapore Singapore Singapore

ISBN: (数字)9798350308396

ISBN: (纸本)9798350308402

Photonic Ising computers hypothetically allow fast solutions to intractable combinatorial optimization problems. We have identified a possible physical implementation involving arrays of injection-locked Vertical Cavity Surface Emitting Lasers and an optical feedback mechanism which allows all-to-all bit connectivity without separate components along each connection path. Time-domain simulations indicate system stability up to at least 16 bits. Experimental realization of polarization switching in injection-locked VCSELs is also demonstrated as a proof-of-concept.

关键词： Computers Stimulated emission Optical feedback Qubit Stability analysis Vertical cavity surface emitting lasers Time-domain analysis Semiconductor laser arrays Optimization Optical arrays

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Practical security of twin-field quantum key distribution with optical phase-locked loop under wavelength-switching attack

arXiv

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arXiv 2024年

作者： Peng, Qingquan Chen, Jiu-Peng Xing, Tianyi Wang, Dongyang Wang, Yizhi Liu, Yang Huang, Anqi Institute for Quantum Information State Key Laboratory of High Performance Computing College of Computer Science and Technology National University of Defense Technology Hunan Changsha410073 China Jinan Institute of Quantum Technology Hefei National Laboratory Jinan Branch Shandong Jinan250101 China

The twin-field class quantum key distribution (TF-class QKD) has experimentally demonstrated the ability to surpass the fundamental rate-distance limit without requiring a quantum repeater, as a revolutional milestone. In TF-class QKD implementation, an optical phase-locked loop (OPLL) structure is commonly employed to generate a reference light with correlated phase, ensuring coherence of optical fields between Alice and Bob. In this configuration, the reference light, typically located in the untrusted station Charlie, solely provides wavelength reference for OPLL and does not participate in quantum-state encoding. However, the reference light may open a door for Eve to enter the source stations that are supposed to be well protected. Here, by identifying vulnerabilities of an acousto-optic modulator (AOM) in the OPLL scheme, we propose and demonstrate a wavelength-switching attack on a TF-class QKD system. This attack involves Eve deliberately manipulating the wavelength of the reference light to increase mean photon number of prepared quantum states, while maintaining stable interference between Alice and Bob as required by TF-class QKD protocols. The maximum observed increase in mean photon number is 8.7%, which has been theoretically proven to compromise the security of a TF-class QKD system. Moreover, we have shown that with well calibration of the modulators, the attack can be eliminated. Through this study, we highlight the importance of system calibration in the practical security in TF-class QKD *** Codes 81P94 Copyright © 2024, The Authors. All rights reserved.

关键词： Modulators

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Estimation of Hamiltonian Parameters from Thermal States

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Physical Review Letters 2024年第4期133卷 040802-040802页

作者： Luis Pedro García-Pintos Kishor Bharti Jacob Bringewatt Hossein Dehghani Adam Ehrenberg Nicole Yunger Halpern Alexey V. Gorshkov Theoretical Division (T4) Joint Center for Quantum Information and Computer Science and Joint Quantum Institute Institute of High Performance Computing (IHPC) Agency for Science Technology and Research (A*STAR) 1 Fusionopolis Way # 16-16 Connexis Singapore 138632 Republic of Singapore Department of Physics Institute for Physical Science and Technology

We upper bound and lower bound the optimal precision with which one can estimate an unknown Hamiltonian parameter via measurements of Gibbs thermal states with a known temperature. The bounds depend on the uncertainty in the Hamiltonian term that contains the parameter and on the term’s degree of noncommutativity with the full Hamiltonian: higher uncertainty and commuting operators lead to better precision. We apply the bounds to show that there exist entangled thermal states such that the parameter can be estimated with an error that decreases faster than 1/n, beating the standard quantum limit. This result governs Hamiltonians where an unknown scalar parameter (e.g., a component of a magnetic field) is coupled locally and identically to n qubit sensors. In the high-temperature regime, our bounds allow for pinpointing the optimal estimation error, up to a constant prefactor. Our bounds generalize to joint estimations of multiple parameters. In this setting, we recover the high-temperature sample scaling derived previously via techniques based on quantum state discrimination and coding theory. In an application, we show that noncommuting conserved quantities hinder the estimation of chemical potentials.

关键词： quantum metrology quantum parameter estimation quantum sensing

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