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Degenerate polarization entangled photon source based on a single Ti-diffusion lithium niobate waveguide in a polarization Sagnac interferometer

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Chinese Physics B 2023年第8期32卷 69-73页

作者：孙宇孙昌伟周唯杨然端家晨龚彦晓徐平祝世宁 National Laboratory of Solid State Microstructures and School of Physics Nanjing UniversityNanjing 210093China NanZhi Institude of Advanced Optoelectronic Integration Nanjing 210018China Institute for Quantum Information and State Key Laboratory of High Performance Computing College of Computer Science and TechnologyNational University of Defense TechnologyChangsha 410073China

Combining a Ti-diffusion periodically poled lithium niobate(PPLN)waveguide with a Sagnac interferometer,two opposite directions type-II spontaneous parametric down conversions(SPDC)occur coherently and yield a high brightness,high stability polarization entanglement *** source produces degenerate photon pairs at 1540.4 nm with a brightness of B=(1.36±0.03)×10^(6) pairs/(s·nm·m W).We perform quantum state tomography to reconstruct the density matrix of the output state and obtain a fidelity of F=0.983±*** high brightness and phase stability of our waveguide source enable a wide range of quantum information experiments operating at a low pump power as well as hold the advantage in mass production which can promote the practical applications of quantum technologies.

关键词： polarization entanglement source Sagnac interferometer quantum information lithium niobate waveguide

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Experimental review on Majorana zero-modes in hybrid nanowires

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Science China(Physics,Mechanics & Astronomy) 2021年第10期64卷 38-53页

作者： Ji-Bang Fu Bin Li Xin-Fang Zhang Guang-Zheng Yu Guang-Yao Huang Ming-Tang Deng Institute for Quantum Information&State Key Laboratory of High Performance Computing College of Computer Science and TechnologyNational University of Defense TechnologyChangsha 410073China

As the condensed matter analog of Majorana fermion, the Majorana zero-mode is well known as a building block of fault-tolerant topological quantum computing. This review focuses on the recent progress of Majorana experiments, especially experiments about semiconductor-superconductor hybrid devices. We first sketch Majorana zero-mode formation from a bottom-up view,which is more suitable for beginners and experimentalists. Then, we survey the status of zero-energy state signatures reported recently, from zero-energy conductance peaks, the oscillations, the quantization, and the interactions with extra degrees of freedom. We also give prospects of future experiments for advancing one-dimensional semiconductor nanowire-superconductor hybrid materials and devices.

关键词： electronic transport in nanoscale materials and structures quantum wires proximity efect superconducting low-dimensional structures

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Context-Driven Index Trimming: A Data Quality Perspective to Enhancing Precision of RALMs

Context-Driven Index Trimming: A Data Quality Perspective to...

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2024 Conference on Empirical Methods in Natural Language Processing, EMNLP 2024

作者： Ma, Kexin Jin, Ruochun Wang, Haotian Wang, Xi Chen, Huan Tang, Yuhua Wang, Qian Institute for Quantum Information State Key Laboratory of High Performance Computing China College of Computer Science and Technology National University of Defense Technology Changsha China Intelligent Game and Decision Lab Academy of Military Science Beijing China

ISBN: (纸本)9798891761681

Retrieval-Augmented Large Language Models (RALMs) have made significant strides in enhancing the accuracy of generated responses. However, existing research often overlooks the data quality issues within retrieval results, often caused by inaccurate existing vector-distance-based retrieval methods. We propose to boost the precision of RALMs' answers from a data quality perspective through the Context-Driven Index Trimming (CDIT) framework, where Context Matching Dependencies (CMDs) are employed as logical data quality rules to capture and regulate the consistency between retrieved contexts. Based on the semantic comprehension capabilities of Large Language Models (LLMs), CDIT can effectively identify and discard retrieval results that are inconsistent with the query context and further modify indexes in the database, thereby improving answer quality. Experiments demonstrate average improvement of 3.75% in accuracy on challenging question-answering tasks. Also, the flexibility of CDIT is verified through its compatibility with various language models and indexing methods, which offers a promising approach to bolster RALMs' data quality and retrieval precision jointly. © 2024 Association for Computational Linguistics.

关键词： Data accuracy

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GPU Parallelization and Optimization of a Combustion Simulation Application 24

GPU Parallelization and Optimization of a Combustion Simulat...

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24th IEEE International Conference on high performance computing and Communications, 8th IEEE International Conference on Data Science and Systems, 20th IEEE International Conference on Smart City and 8th IEEE International Conference on Dependability in Sensor, Cloud and Big Data Systems and Application, HPCC/DSS/SmartCity/DependSys 2022

作者： Liao, Zhixiang Liu, Yongzhou Che, Yonggang Institute for Quantum Information College of Computer National University of Defense Technology State Key Laboratory of High Performance Computing Changsha China

ISBN: (纸本)9798350319934

Graphics processing units (GPUs) are widely used in the area of scientific computing. While GPUs provide much higher peak performance, efficient implementation of real applications on the GPU architectures is still a non-trivial task. It is crucial to realize efficient solution algorithms that can better utilize GPU architectures. This paper presents our efforts in parallelizing and optimizing LESAP, a CFD application for scramjet combustion simulation, on NVIDIA GPUs. The GPU parallelization is realized based on the CUDA programming model, with a data-parallel implicit time-marching method that is efficient on the GPU architecture. Furthermore, shared memory and redundant calculation are proposed to reduce memory access overhead during GPU computation, and data transfer between CPU and GPU is optimized by packing the data to be transferred. The experimental results show that the GPU version, when runs on four V100 GPUs, achieves a speedup of 11.26 times compared to the CPU version that runs on two 24-core Intel Skylake Gold 6240R CPUs. Excellent parallel scalability across multiple GPUs is also observed. © 2022 IEEE.

关键词： Graphics processing unit

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quantum Relaxation for Solving Multiple Knapsack Problems

arXiv

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arXiv 2024年

作者： Sharma, Monit Yan, Jin Lau, Hoong Chuin Raymond, Rudy School of Computing and Information Systems Singapore Management University Singapore Institute of High Performance Computing A*STAR Singapore IBM Quantum IBM Japan Japan

Combinatorial problems are a common challenge in business, requiring finding optimal solutions under specified constraints. While significant progress has been made with variational approaches such as QAOA, most problems addressed are unconstrained (such as Max-Cut). In this study, we investigate a hybrid quantum-classical method for constrained optimization problems, particularly those with knapsack constraints that occur frequently in financial and supply chain applications. Our proposed method relies firstly on relaxations to local quantum Hamiltonians, defined through commutative maps. Drawing inspiration from quantum random access code (QRAC) concepts, particularly quantum Random Access Optimizer (QRAO), we explore QRAO’s potential in solving large constrained optimization problems. We employ classical techniques like Linear Relaxation as a presolve mechanism to handle constraints and cope further with scalability. We compare our approach with QAOA and present the final results for a real-world procurement optimization problem: a significant-sized multi-knapsack-constrained problem. © 2024, CC BY.

关键词： Constrained optimization

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Toward to Real Low-Resolution Person Re-identification: A New Dataset and Baseline

Toward to Real Low-Resolution Person Re-identification: A Ne...

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2022 IEEE International Conference on Multimedia and Expo, ICME 2022

作者： Sun, Dongting Yang, Lulu Lan, Long Luo, Zhigang College of Computer Science and Technology National University of Defense Technology Institute for Quantum Information State Key Laboratory of High Performance Computing China

ISBN: (数字)9781665485630

ISBN: (纸本)9781665485630

Person re-identification(re-id) aims at querying and identifying the same target pedestrian in multiple non-overlapping cameras. However, in real scenarios, many person images captured by surveillance cameras tend to have low resolution due to camera hardware, shooting distance, viewing angle, etc. Many existing re-id methods mainly address the crossresolution person re-id problem, i.e., the high-low resolution mismatch problem. In contrast, the problem of matching low-resolution (LR) gallery images and query images with each other has been less studied. In this paper, we address this problem by developing a new gun-ball camera-based person re-id dataset and designing a LR re-id baseline model for this dataset to tackle the LR person matching problem. Extensive experiments validate the effectiveness of the proposed LR baseline model. © 2022 IEEE.

关键词： Cameras

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Bandwidth-tunable silicon nitride microring resonators

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Chinese Physics B 2022年第1期31卷 263-266页

作者： Jiacheng Liu Chao Wu Gongyu Xia Qilin Zheng Zhihong Zhu Ping Xu Hunan Provincial Key Laboratory of Novel Nano-Optoelectronic Information Materials and Device Institute for Quantum Information and State Key Laboratory of High Performance ComputingCollege of Advanced Interdisciplinary Studies&College of ComputerNational University of Defense TechnologyChangsha 410073China

We designed a reconfigurable dual-interferometer coupled silicon nitride microring *** tuning the integrated heater on interferometer's arms,the"critical coupling"bandwidth of resonant mode is continuously adjustable whose quality factor varies from 7.9×10^(4) to 1.9×10^(5) with the extinction ratio keeping higher than 25 *** a variety of coupling spanning from"under-coupling"to"over-coupling"were achieved,showing the ability to tune the quality factor from 6.0×10^(3) to 2.3×10^(5).Our design can provide an adjustable filtering method on silicon nitride photonic chip and contribute to optimize the nonlinear process for quantum photonics and all-optical signal processing.

关键词： silicon nitride microring resonators Mach-Zehnder interferometer ring filter nonlinear optics

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Detecting galaxy – 21-cm cross-correlation during reionization

arXiv

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arXiv 2025年

作者： Gagnon-Hartman, Samuel Davies, James Mesinger, Andrei Scuola Normale Superiore di Pisa Piazza dei Cavallieri 7 Pisa56126 Italy Centro Nazionale "High Performance Computing Big Data and Quantum Computing" Italy

The cosmic 21-cm signal promises to revolutionize studies of the Epoch of Reionization (EoR). Radio interferometers are aiming for a preliminary, low signal-to-noise (S/N) detection of the 21-cm power spectrum. Cross-correlating 21-cm with galaxies will be especially useful in these efforts, providing both a sanity check for initial 21-cm detection claims and potentially increasing the S/N due to uncorrelated residual systematics. Here we self-consistently simulate large-scale (1 Gpc3) galaxy and 21-cm fields, computing their cross-power spectra for various choices of instruments as well as survey properties. We use 1080h observations with SKA-low AA* and HERA-350 as our benchmark 21-cm observations. We create mock Lyman alpha narrow-band, slitless and slit spectroscopic surveys, using benchmarks from instruments such as Subaru HyperSupremeCam, Roman grism, VLT MOONS, ELT MOSAIC, and JWST NIRCam. We forecast the resulting S/N of the galaxy–21-cm cross-power spectrum, varying the galaxy survey area, depth and level of 21-cm foreground contamination for each pair of instruments. We find that the highest S/N is achievable through slitless, wide-area spectroscopic surveys, with the proposed Roman HLS survey resulting in a ∼ 55σ (∼ 13σ) detection of the cross power with 21-cm as observed with SKA-low AA* (HERA-350), for our fiducial model and assuming ∼500 sq. deg. of overlap. Narrow-band dropout surveys are unlikely to result in a detectable cross-power, due to their poor redshift localization. Slit spectroscopy can provide a high S/N detection of the cross power for SKA-low AA* observations. Specifically, the planned MOONRISE survey with MOONS on the VLT can result in a ∼ 3σ detection, while a survey of comparable observing time using MOSAIC on the ELT can result in a ∼ 4σ detection. Our results can be used to guide survey strategies, facilitating the detection of the galaxy–21-cm cross-power spectrum. © 2025, CC BY.

关键词： Signal to noise ratio

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The Optimization of Multi-physics Application Simulated by Lattice Boltzmann Method Based on Domestic Processors 23

The Optimization of Multi-physics Application Simulated by L...

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2nd International Conference on Networks, Communications and Information Technology, CNCIT 2023

作者： Liu, Yi Peng, Lin Zhang, Peng Qiu, Yan Long Zhang, Sen Guo, Xiaowei Yang, Canqun College of Computer National University of Defense Technology Hunan Changsha China Institute for Quantum Information State Key Laboratory of High Performance Computing College of Computer National University of Defense Technology Hunan Changsha China

ISBN: (纸本)9798400700620

LBM can conveniently deal with the interaction between fluid and solid. Thus, it is widely used in numerical simulation of multi-physics applications. Based on the domestic processor FT-2000, the numerical simulation of Rayleigh-Bnard convection is carried out. Through performance tests, it is found that the function call overhead of the numerical simulation process occupies nearly of the execution time. By expanding the function call process and reorganizing the data structure, the simulation time for 104 simulation timestep declines from 9236s to 2754s, and the simulation performance of Rayleigh-Bnard convection has improved about . © 2023 ACM.

关键词： Kinetic theory

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BioNet+: A Comprehensive Interaction Model of Finding Therapeutics for Diseases with Graph Deep Learning 25

BioNet+: A Comprehensive Interaction Model of Finding Therap...

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25th IEEE International Conferences on high performance computing and Communications, 9th International Conference on Data Science and Systems, 21st IEEE International Conference on Smart City and 9th IEEE International Conference on Dependability in Sensor, Cloud and Big Data Systems and Applications, HPCC/DSS/SmartCity/DependSys 2023

作者： Ma, Jinglun Qiu, Yanlong Yang, Canqun Wu, Chengkun Institute for Quantum Information State Key Laboratory of High Performance Computing National University of Defense Technology Changsha410073 China College of Computer Science and Techology National University of Defense Technology Changsha410073 China

ISBN: (纸本)9798350330014

The prediction of interactions between biomedical entities is crucial for the discovery of therapeutics for diseases. The fundamental step is to build an interaction model with a comprehensive coverage on literature and curated databases. The massive amount of heterogeneous data in interaction networks of biomedical entities poses significant challenges to relevant prediction tasks. Previous research has mainly focused on constructing networks with limited types of entity relations. In this paper, we construct a large-scale heterogeneous graph model, BioNet+, using a data-driven approach to extract latent information and predict various relations among biomedical entities. BioNet+ provides a crucial update to our previous BioNet model, with the addition of disease entities. The model employs a graph convolution encoder to learn embedding information from the intricate interactions among chemicals (C), genes (G), diseases (D), and biological pathways (P). Furthermore, a decoder that applies two tensor decomposition methods is deployed to predict multiple types of relations, including CG, CD, and GD interactions. The model constructs a graph network consisting of 81,987 entity nodes and 206,195,703 interaction edges. To handle this massive model, BioNet+ reduces the computational complexity via data categorization and proposes a parallel model training algorithm for cross-node GPUs. Evaluation experiments demonstrate that BioNet+ achieves superior predictive performance, as demonstrated by its highest area under the receiver operating characteristic curve (AUROC) of 0.964. © 2023 IEEE.

关键词： Forecasting

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