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Gain-Loss Coupled Systems

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arXiv 2024年

作者： Zhang, Chunlei Kim, Mun Zhang, Yi-Hui Wang, Yi-Pu Trivedi, Deepanshu Krasnok, Alex Wang, Jianbo Isleifson, Dustin Roshko, Roy Hu, Can-Ming Department of Physics and Astronomy University of Manitoba WinnipegMBR3T 2N2 Canada Zhejiang Key Laboratory of Micro-Nano Quantum Chips and Quantum Control School of Physics State Key Laboratory for Extreme Photonics and Instrumentation Zhejiang University Hangzhou310027 China Department of Electrical and Computer Engineering Florida International University MiamiFL33174 United States School of Physical Science and Technology Lanzhou University Lanzhou730000 China Department of Electrical and Computer Engineering University of Manitoba WinnipegMBR3T 5V6 Canada

Achieving oscillations with small dimensions, high power, high coherence, and low phase noise has been a longstanding goal in wave physics, driving innovations across classical electromagnetic theory and quantum physics. Key applications include electronic oscillators, lasers, and spin-torque oscillations. In recent decades, physicists have increasingly focused on harnessing passive oscillatory modes to manipulate these oscillations, leading to the development of diverse gain-loss coupled systems, including photon-photon, exciton-photon, photon-magnon, magnon-phonon, and magnon-magnon couplings. This review provides a comprehensive overview of these systems, exploring their fundamental physical structures, key experimental observations, and theoretical insights. By synthesizing insights from these studies, we propose future research directions to further advance the understanding and application of gain-loss coupled systems for quantum science and quantum technologies. (The field of gain-loss coupled systems is vast. The authors welcome suggestions and feedback from the community to continuously improve this review article until it is published). Copyright © 2024, The Authors. All rights reserved.

关键词： Photons

Supply Function Equilibrium in Networked Electricity Markets

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arXiv 2023年

作者： Xiao, Yuanzhang Bandi, Chaithanya Wei, Ermin Hawaii Advanced Wireless Technologies Institute University of Hawaii HonoluluHI96816 United States Kellogg School of Management Northwestern University EvanstonIL60208 United States Department of Electrical Engineering and Computer Science Northwestern University EvanstonIL60208 United States

We study deregulated power markets with strategic power suppliers. In deregulated markets, each supplier submits its supply function (i.e., the amount of electricity it is willing to produce at various prices) to the independent system operator (ISO), who based on the submitted supply functions, dispatches the suppliers to clear the market with minimal total generation cost. If all suppliers reported their true marginal cost functions as supply functions, the market outcome would be efficient (i.e., the total generation cost is minimized). However, when suppliers are strategic and aim to maximize their own profits, the reported supply functions are not necessarily the true marginal cost functions, and the resulting market outcome may be inefficient. The efficiency loss depends crucially on the topology of the underlying transmission network. This paper provides an analytical upper bound of the efficiency loss due to strategic suppliers, and proves that the bound is tight under a large class of transmission networks (i.e., weakly cyclic networks). Our upper bound sheds light on how the efficiency loss depends on the transmission network topology (e.g., the degrees of nodes, the admittances and flow limits of transmission lines). © 2023, CC BY.

关键词： Cost functions

Survey of Spectral Amplitude Coding Optical Code Division Multiple Access Families

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Journal of Lightwave Technology 2025年

作者： Ullah, Rahat Ullah, Sibghat Ali, Aitizaz Jianxin, Ren Alwageed, Hathal Salamah Yaya, Mao Qi, Zhipeng Yu, Yongyi Imtiaz, Waqas A. Khan, Maqbool School of Physics and Optoelectronics Nanjing University of Information Science and Technology China Jiangsu Key Laboratory for Optoelectronic Detection of Atmosphere and Ocean Nanjing University of Information Science Technology Nanjing210044 China Jiangsu International Joint Laboratory on Meteorological Photonics and Optoelectronic Detection Nanjing University of Information Science Technology Nanjing210044 China School of Electronics Science and Technology Southeast University China School of Technology NSF Group Asia Pacific University Malaysia Saudi Arabia College of Computer Science Jouf University Saudi Arabia Electrical Engineering Department University of Engineering and Technology Peshawar Pakistan Pak-Austra Fachhochschule Haripur Pakistan

Quest for high capacity communication have led the research community to explore a plethora of technologies. Among these, optical code division multiple access (OCDMA) technique stands tall with support for high data rate connectivity in terms of data, reach and the number of subscribers. The development of OCDMA based networks started with the design and implementation of one dimensional (1D) codes, which provides effective correlation properties to reduce the effect of interference due to multiple users (MAI) and phase-induced-intensity-noise (PIIN) in order to provide the required system capacity. Several families of codes have been developed to determine the most suitable combination between code length, weight against the auto- and cross-correlation property respectively. This survey paper will analyze the most commonly used families of codes from spectral amplitude coding (SAC) based OCDMA systems names Double Weight (DW) codes, Diagonal codes , zero cross-correlation (ZCC) codes, and hybrid codes in terms of different performance parameters and identify the most suitable combination of code length (L), code weight (w), and cross-correlation (λC) to be utilized for next generation communication applications that can provide high capacity and cardinality. © 1983-2012 IEEE.

关键词： Passive optical networks

Periodically driven open quantum systems: Spectral properties and nonequilibrium steady states

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Physical Review B 2024年第18期109卷 184309-184309页

作者： Hao Chen Yu-Min Hu Wucheng Zhang Michael Alexander Kurniawan Yuelin Shao Xueqi Chen Abhinav Prem Xi Dai Department of Physics Princeton University New Jersey 08544 USA Department of Electrical and Computer Engineering Princeton University New Jersey 08544 USA Institute for Advanced Study Tsinghua University Beijing 100084 China Department of Physics Hong Kong University of Science and Technology Clear Water Bay Road Kowloon Hong Kong China Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing 100190 China School of Physical Sciences University of Chinese Academy of Sciences Beijing 100049 China Department of Physics Stanford University Stanford California 94305 USA School of Natural Sciences Institute for Advanced Study Princeton New Jersey 08540 USA

In this paper, we investigate periodically driven open quantum systems within the framework of Floquet-Lindblad master equations. Specifically, we discuss Lindblad master equations in the presence of a coherent, time-periodic driving and establish their general spectral features. We also clarify the notions of transient and nondecaying solutions from this spectral perspective, and then prove that any physical system described by a Floquet-Lindblad equation must have at least one physical nonequilibrium steady state (NESS), corresponding to an eigenoperator of the Floquet-Lindblad evolution superoperator UF with unit eigenvalue. Since the Floquet-Lindblad formalism encapsulates the entire information regarding the NESS, it in principle enables us to obtain nonlinear effects to all orders at once. The Floquet-Lindblad formalism thus provides a powerful tool for studying driven-dissipative solid-state systems, which we illustrate by deriving the nonlinear optical response of a simple two-band model of an insulating solid and comparing it with prior results established through Keldysh techniques.

关键词： Nonlinear optics Open quantum systems & decoherence Floquet systems Lindblad equation

Data-Driven Wireless Anomaly Detection Using Spectral Features

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Data-Driven Wireless Anomaly Detection Using Spectral Featur...

MILCOM, Military Communications Conference

作者： Stephan Frisbie Mohamed Younis The Johns Hopkins University Applied Physics Laboratory Laurel Maryland United States Department of Computer Science and Electrical Engineering University of Maryland Baltimore County Baltimore Maryland United States

In this work, we present an anomaly detection algorithm for wireless spectrum data and evaluate its ability to accurately detect interfering transmissions. The algorithm considers three types of interfering signals: a co-channel transmission, an interfering continuous-wave transmission, or an adversarial replay attack. At the core of each anomaly detector is a feature space transformation, which learns a compressed representation of the data, followed by various metrics on this representation. Four feature space transformations and four detection metrics are investigated, each of which represents different characterizations of the distribution of the data, totaling 16 configurations of the anomaly detector. Our algorithm is evaluated using Wi-Fi spectrum data from real-world radio frequency (RF) captures in both mild and harsh channel conditions. We present an analysis of the performance of the various configurations under each of the interference types at varying signal-to-interference ratios. Lastly, we discuss the implications of this performance on the the distribution of the data and the recommended model to detect each type of anomaly.

关键词： Training Spatial diversity Interference Detectors Feature extraction Extraterrestrial measurements Anomaly detection

Giant photothermoelectric effect in silicon nanoribbon photodetectors

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Light(science & Applications) 2020年第1期9卷 853-860页

作者： Wei Dai Weikang Liu Jian Yang Chao Xu Alessandro Alabastri Chang Liu Peter Nordlander Zhiqiang Guan Hongxing Xu School of Physics and Technology Center for Nanoscience and Nanotechnologyand Key Laboratory of Artificial Micro-and Nano-structures of Ministry of EducationWuhan UniversityWuhan 430072China Department of Physics and Astronomy Department of Electrical and Computer Engineering and Laboratory for NanophotonicsRice UniversityHoustonTX 77005USA The Institute for Advanced Studies Wuhan UniversityWuhan 430072China

The photothermoelectric(PTE)effect enables efficient harvesting of the energy of photogenerated hot carriers and is a promising choice for high-efficiency photoelectric energy conversion and ***,the PTE effect was reported in low-dimensional nanomaterials,suggesting the possibility of optimizing their energy conversion ***,the PTE effect becomes extremely inefficient in low-dimensional nanomaterials,owing to intrinsic disadvantages,such as low optical absorption and immature fabrication *** this study,a giant PTE effect was observed in lightly doped p-type silicon nanoribbons caused by photogenerated hot *** open-circuit photovoltage responsivity of the device was 3-4 orders of magnitude higher than those of previously reported PTE *** measured photovoltage responses fit very well with the proposed photothermoelectric multiphysics *** research proposes an application of the PTE effect and a possible method for utilizing hot carriers in semiconductors to significantly improve their photoelectric conversion efficiency.

关键词： effect utilizing enable

EPRD: Exploiting prior knowledge for evidence-providing automatic rumor detection

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Neurocomputing 2024年 563卷

作者： Li, Jiawen Li, Ronghui Ni, Shiwen Kao, Hung-Yu Naval Architecture and Shipping College Guangdong Ocean University Guangdong Zhanjiang524000 China Technical Research Center for Ship Intelligence and Safety Engineering of Guangdong Province Guangdong Zhanjiang524000 China Intelligent Knowledge Management Lab National Cheng Kung University Tainan Taiwan Department of Computer Science and Information Engineering National Cheng Kung University Tainan Taiwan Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen China

With the prevalence of social media platforms, rumors have been a serious social problem. Notably, existing rumor detection methods simply provide detection labels while ignoring their explanation. However, illustrating the reasons why a suspicious statement is a rumor is essential. To address this realistic scenario, we propose a novel Evidence-Providing Rumor Detection model called EPRD. EPRD incorporates a wide variety of information from both prior knowledge sources and current comments. It also learns bilaterally friendly representations for interpretable rumor detection. EPRD first retrieves evidence from prior knowledge sources and checks the relationship between the given statement and its evidence. Our model then constructs two heterogeneous graph objects to simulate the propagation layout of the current comments and evidence relationships. Finally, EPRD integrates the GraphSAGE component and attention mechanism to detect rumors. To the best of our knowledge, we propose the first model that incorporates prior knowledge to verify rumors and boost credibility. Experiments on two real-world Twitter datasets demonstrate that EPRD consistently exhibits the best rumor detection performance. Moreover, EPRD outperforms other baselines in the early rumor detection task. © 2023

关键词： Graph neural networks

Operation-Level Performance Benchmarking of Graph Neural Networks for Scientific Applications

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arXiv 2022年

作者： Hosseini, Ryien Simini, Filippo Vishwanath, Venkatram Argonne Leadership Computing Facility Argonne National Laboratory Lemont IL United States Department of Electrical Engineering and Computer Science University of Michigan Ann ArborMI United States

As Graph Neural Networks (GNNs) increase in popularity for scientific machine learning, their training and inference efficiency is becoming increasingly critical. Additionally, the deep learning field as a whole is trending towards wider and deeper networks, and ever increasing data sizes, to the point where hard hardware bottlenecks are often encountered. Emerging specialty hardware platforms provide an exciting solution to this problem. In this paper, we systematically profile and select low-level operations pertinent to GNNs for scientific computing implemented in the Pytorch Geometric software framework. These are then rigorously benchmarked on NVIDIA A100 GPUs for several various combinations of input values, including tensor sparsity. We then analyze these results for each operation. At a high level, we conclude that on NVIDIA systems: (1) confounding bottlenecks such as memory inefficiency often dominate runtime costs moreso than data sparsity alone, (2) native Pytorch operations are often as or more competitive than their Pytorch Geometric equivalents, especially at low to moderate levels of input data sparsity, and (3) many operations central to state-of-the-art GNN architectures have little to no optimization for sparsity. We hope that these results serve as a baseline for those developing these operations on specialized hardware and that our subsequent analysis helps to facilitate future software and hardware based optimizations of these operations and thus scalable GNN performance as a whole. © 2022, CC BY.

关键词： Graph neural networks

Multi-Task Semantic Communications via Large Models

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arXiv 2025年

作者： Ni, Wanli Qin, Zhijin Sun, Haofeng Tao, Xiaoming Han, Zhu Department of Electronic Engineering Tsinghua University Beijing100084 China State Key Laboratory of Space Network and Communications Beijing100084 China Beijing National Research Center for Information Science and Technology Beijing100084 China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing100876 China Electrical and Computer Engineering University of Houston HoustonTX77004 United States

Artificial intelligence (AI) promises to revolutionize the design, optimization and management of next-generation communication systems. In this article, we explore the integration of large AI models (LAMs) into semantic communications (SemCom) by leveraging their multi-modal data processing and generation capabilities. Although LAMs bring unprecedented abilities to extract semantics from raw data, this integration entails multifaceted challenges including high resource demands, model complexity, and the need for adaptability across diverse modalities and tasks. To overcome these challenges, we propose a LAM-based multi-task SemCom (MTSC) architecture, which includes an adaptive model compression strategy and a federated split fine-tuning approach to facilitate the efficient deployment of LAM-based semantic models in resource-limited networks. Furthermore, a retrieval-augmented generation scheme is implemented to synthesize the most recent local and global knowledge bases to enhance the accuracy of semantic extraction and content generation, thereby improving the inference performance. Finally, simulation results demonstrate the efficacy of the proposed LAM-based MTSC architecture, highlighting the performance enhancements across various downstream tasks under varying channel conditions. Copyright © 2025, The Authors. All rights reserved.

关键词： Data integration