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Science Bulletin 2024年第11期69卷 1738-1747页

作者：李远宁杨虎铮顾实 School of Biomedical Engineering&State Key Laboratory of Advanced Medical Materials and Devices ShanghaiTech UniversityShanghai 201210China School of Computer Science and Engineering University of Electronic Science and Technology of ChinaChengdu 611731China Department of Computer and Information Science University of PennsylvaniaPhiladelphiaPA 19104USA Shenzhen Institute for Advanced Study University of Electronic Science and Technology of ChinaShenzhen 518110China

Cognitive neuroscience aims to develop computational models that can accurately predict and explain neural responses to sensory inputs in the cortex. Recent studies attempt to leverage the representation power of deep neural networks(DNNs) to predict the brain response and suggest a correspondence between artificial and biological neural networks in their feature representations. However, typical voxel-wise encoding models tend to rely on specific networks designed for computer vision tasks, leading to suboptimal brain-wide correspondence during cognitive tasks. To address this challenge, this work proposes a novel approach that upgrades voxel-wise encoding models through multi-level integration of features from DNNs and information from brain networks. Our approach combines DNN feature-level ensemble learning and brain atlas-level model integration, resulting in significant improvements in predicting whole-brain neural activity during naturalistic video perception. Furthermore, this multi-level integration framework enables a deeper understanding of the brain's neural representation mechanism, accurately predicting the neural response to complex visual concepts. We demonstrate that neural encoding models can be optimized by leveraging a framework that integrates both data-driven approaches and theoretical insights into the functional structure of the cortical networks.

关键词： Neural encoding Visual perception Artificial neural networks Functional neuroimaging Naturalistic stimuli

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Emergence of composite many-body exciton states in WS2 and MoSe2 monolayers

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Physical Review B 2024年第4期109卷 L041304-L041304页

作者： J. Choi J. Li D. Van Tuan H. Dery S. A. Crooker National High Magnetic Field Laboratory Los Alamos New Mexico 87545 USA Advanced Instrumentation Institute Korea Research Institute of Standards and Science Daejeon 34113 Korea Wuhan National High Magnetic Field Center and School of Physics Huazhong University of Science and Technology Hubei 430074 China Department of Electrical and Computer Engineering University of Rochester Rochester New York 14627 USA Department of Physics and Astronomy University of Rochester Rochester New York 14627 USA

When doped with a high density of mobile charge carriers, monolayer transition-metal dichalcogenide (TMD) semiconductors can host new types of composite many-particle exciton states that do not exist in conventional semiconductors. Such multiparticle bound states arise when a photoexcited electron-hole pair couples not to just a single Fermi sea that is quantum-mechanically distinguishable (as in the case of conventional charged excitons or trions), but rather couples simultaneously to multiple Fermi seas, each having distinct spin and valley quantum numbers. Composite six-particle “hexciton” states were recently identified in electron-doped WSe2 monolayers, but under suitable conditions they should also form in all other members of the monolayer TMD family. Here we present spectroscopic evidence demonstrating the emergence of many-body hexcitons in charge-tunable WS2 monolayers (at the A-exciton) and MoSe2 monolayers (at the B-exciton). The roles of distinguishability and carrier screening on the stability of hexcitons are discussed.

关键词： Excitons Trions Transition metal dichalcogenides Two-dimensional electron system

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Stable Symmetry-Protected Topological Phases in Systems with Heralded Noise

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Physical Review Letters 2025年第1期134卷 010403-010403页

作者： Sanket Chirame Fiona J. Burnell Sarang Gopalakrishnan Abhinav Prem School of Physics and Astronomy University of Minnesota Minneapolis Minnesota 55455 USA Department of Electrical and Computer Engineering Princeton University Princeton New Jersey 08544 USA School of Natural Sciences Institute for Advanced Study Princeton New Jersey 08540 USA

We present a family of local quantum channels whose steady states exhibit stable mixed-state symmetry-protected topological (SPT) order. Motivated by recent experimental progress on “erasure conversion” techniques that allow one to identify (herald) decoherence processes, we consider open systems with biased erasure noise, which leads to strongly symmetric heralded errors. We utilize this heralding to construct a local correction protocol that effectively confines errors into short-ranged pairs in the steady state. Using a combination of numerical simulations and mean-field analysis, we show that our protocol stabilizes SPT order against a sufficiently low rate of decoherence. As the rate of heralded noise increases, SPT order is eventually lost through a directed percolation transition. We further find that while introducing unheralded errors destroys SPT order in the limit of long length scales and timescales, the correction protocol is sufficient for ensuring that local SPT order persists, with a correlation length that diverges as ξ∼(1−fe)−1/2, where fe is the fraction of errors that are heralded.

关键词： Quantum channel

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Parametric Optimization and Mathematical Analysis of Dual Halide Lead Free Perovskite Solar Cell 2

Parametric Optimization and Mathematical Analysis of Dual Ha...

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2nd International Conference Computational and Characterization Techniques in engineering and Sciences, IC3TES 2024

作者： Sharma, Sakshi Kumar, Kaushal Khan, Baseem Pachauri, Rupendra Kumar Kumar Gupta, Ankur Hawassa University Department of Electrical and Computer Engineering Hawassa05 Ethiopia Upes School of Advanced Engineering Dehradun248007 India International University if Business Agriculture and Technology Miyan Research Institute of Technology Dhaka1230 Bangladesh Iimt University R&d Department Meerut India

ISBN: (纸本)9798350364699

The scientific community has recently taken an interest in perovskite solar cells, often known as PSCs. Dual halide PSC has the best efficiency reported in the literature at 20.9%. The purpose of this work is to improve a lead-free dual halide photovoltaic (PSC) by modifying the material of the hole transport layer (HTL) and the electron transport layer (ETL), as well as regulating the thickness of the absorber layer. In order to evaluate the device, the following metrics are taken into consideration: fill factor (FF), power conversion efficiency (PCE), open circuit voltage (VOC), and short circuit current density (JSC). With optimization, the gadget can reach an efficiency level of 24.03%. Further investigation into a tandem or dual structure method may be possible with this work. © 2024 IEEE.

关键词： Perovskite solar cells

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Physics-informed tracking of qubit fluctuations

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Physical Review Applied 2024年第1期22卷 014033-014033页

作者： Fabrizio Berritta Jan A. Krzywda Jacob Benestad Joost van der Heijden Federico Fedele Saeed Fallahi Geoffrey C. Gardner Michael J. Manfra Evert van Nieuwenburg Jeroen Danon Anasua Chatterjee Ferdinand Kuemmeth Center for Quantum Devices Lorentz Institute and Leiden Institute of Advanced Computer Science Center for Quantum Spintronics Department of Physics QDevil Quantum Machines 2750 Ballerup Denmark Department of Engineering Science Department of Physics and Astronomy Birck Nanotechnology Center Elmore Family School of Electrical and Computer Engineering School of Materials Engineering

Environmental fluctuations degrade the performance of solid-state qubits but can in principle be mitigated by real-time Hamiltonian estimation down to timescales set by the estimation efficiency. We implement a physics-informed and an adaptive Bayesian estimation strategy and apply them in real time to a semiconductor spin qubit. The physics-informed strategy propagates a probability distribution inside the quantum controller according to the Fokker-Planck equation, appropriate for describing the effects of nuclear spin diffusion in gallium arsenide. Evaluating and narrowing the anticipated distribution by a predetermined qubit probe sequence enables improved dynamical tracking of the uncontrolled magnetic field gradient within the singlet-triplet qubit. The adaptive strategy replaces the probe sequence by a small number of qubit probe cycles, with each probe time conditioned on the previous measurement outcomes, thereby further increasing the estimation efficiency. The combined real-time estimation strategy efficiently tracks low-frequency nuclear spin fluctuations in solid-state qubits, and can be applied to other qubit platforms by tailoring the appropriate update equation to capture their distinct noise sources.

关键词： Quantum control Quantum fluctuations & noise Quantum information with solid state qubits Double quantum dots Bayesian methods Fokker–Planck equation Machine learning Radio frequency techniques

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Passenger Trajectory Model and Passenger Movement Estimation Algorithm for Preventing Passenger Subway Door Accidents

SSRN

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SSRN 2024年

作者： Jo, Hee Li, Yifan Lim, Lisa Chong, Jo Woon Department of Electrical and Computer Engineering Sungkyunkwan University Korea Republic of Department of Electrical and Computer Engineering Texas Tech University United States Department of Civil and Environmental Engineering Korea Advanced Institute of Science and Technology Korea Republic of

Passengers being caught in the subway doors can result in unexpected waiting times of passengers and even fatal consequences. A safe and rapid closing of subway doors is imperative to increasing passenger safety and reducing dwell time in metropolitan railway systems. Identifying passengers at risk of being caught in subway doors can help prevent such accidents. In this paper, we develop a passenger trajectory model by analyzing the behavior of passengers descending the platform stairs and rushing to train doors. Combined with this analyzed passenger movement model, we propose a deep learning-based method for detecting the three types of movement activities, which is applied to determine a safe method of closing the door. Based on the experimental results of the images of the stairs collected using CCTV cameras installed in front of the stairs and their adjacent platforms, our method can detect passengers' movements on the stairs in real-time with an accuracy of 96.03%. As a result, the proposed model is expected to prevent relevant safety accidents/incidents and reduce subway unexpected waiting time on the platform. © 2024, The Authors. All rights reserved.

关键词： Subways

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Microwave-induced cooling in double quantum dots: Achieving millikelvin temperatures to reduce thermal noise around spin qubits

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Physical Review B 2025年第1期111卷 014305-014305页

作者： Daryoosh Vashaee Jahanfar Abouie Department of Materials Science and Engineering and Department of Electrical and Computer Engineering North Carolina State University Raleigh North Carolina 27606 USA Department of Physics Institute for Advanced Studies in Basic Sciences Zanjan 45137-66731 Iran

Spin qubits in gate-defined quantum dots are emerging as a leading technology due to their scalability and long coherence times. However, maintaining these qubits at ultralow temperatures typically requires complex cryogenic systems. This paper proposes a gate-defined double quantum dot (DQD) cooling system, where the DQDs act as refrigerants to reduce the local phonon environment around computational qubits. The cooling process occurs in two distinct stages: the first step involves microwave-induced state depopulation combined with fast cyclic detuning to transfer the DQD's population to the ground state, effectively lowering the DQD's temperature. In the second step, the cooled DQD interacts with and absorbs phonons resonant with the DQD spin energy, thereby filtering out these phonons that contribute to spin-lattice relaxation in the surrounding environment. This study focuses on the first step, presenting detailed calculations and numerical results that demonstrate the feasibility of achieving local DQD temperatures below 10mK at a bath temperature of 1K. The sensitivity of the cooling performance to detuning energy, magnetic field strength, spin-orbit couplings, and diabatic return time is analyzed, while the phonon filtering in the second step will require further investigation.

关键词： Semiconductor quantum dots

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Analysis of Reinforcement Learning Schemes for Trajectory Optimization of an Aerial Radio Unit

Analysis of Reinforcement Learning Schemes for Trajectory Op...

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IEEE International Conference on Communications (ICC)

作者： Hossein Mohammadi Vuk Marojevic Bodong Shang Department of Electrical and Computer Engineering Mississippi State University Mississippi State MS USA Eastern Institute for Advanced Study Ningbo China

This paper introduces the deployment of unmanned aerial vehicles (UAVs) as lightweight wireless access points that leverage the fixed infrastructure in the context of the emerging open radio access network (O-RAN). More precisely, we introduce the aerial radio unit (A-RU) that dynamically serves an underserved area and connects to the distributed unit (ODU) via a wireless fronthaul between the UAV and the closest fixed network infrastructure tower. In this paper we employ artificial intelligence (AI) for determining the UAV trajectory for serving User Equipment (UEs) while maintaining the fronthaul connectivity to the O-DU at the same time in a multiple-input multiple-output (MIMO) fading channel. We first formulate the trajectory time and throughput rate; however, owing to the nonconvexity of the problem of maximizing the network throughput based on UAV location, we put our effort to achieve these goals by RL approach. Three different approaches have been presented. We first divide the area into a grid and let the UAV explore the environment by flying from point A to point B using both the offline Q-learning and the online SARSA algorithm and the pathloss as the reward. With the intention of maximizing the average payoff, the trajectory in the first scenario is described as a Markov decision process (MDP). According to simulations, MDP produces better results in a smaller area and in less time. In contrast, SARSA performs better in larger environments at the expense of a longer flight duration.

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SANERV: Scene-Adaptive Neural Representation for Videos

SANERV: Scene-Adaptive Neural Representation for Videos

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IEEE International Conference on Image Processing

作者： Hochang Rhee Hae Soo Chung Jun Ho Jo Eun Ji Lee Nam Ik Cho Samsung Advanced Institute of Technology Department of Electrical and Computer Engineering INMC Seoul National University Seoul Korea

ISBN: (数字)9798350349399

ISBN: (纸本)9798350349405

Neural Representations for Videos (NeRV) is a neural network model that learns video representation through image-wise implicit neural representation (INR). Although early NeRV-based research has improved representation learning, it overlooked video properties. In this paper, we propose a new method called Scene-Adaptive Neural Representation for Videos (SANeRV) that considers videos’ general properties and adapts to individual video characteristics. To achieve this, we incorporate temporal redundancy, which is a typical feature of videos, by splitting the learning process into two parts: global representation and residual representation. Moreover, we adjust the network architecture based on the presence of scene changes and the dynamism of the video to cater to individual video characteristics. Experiments show that SANeRV achieves state-of-the-art performance in video regression and compression tasks for benchmark datasets.

关键词： Representation learning Adaptation models Image coding Tensors Redundancy Neural networks Network architecture

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Recent advances in acoustofluidic separation technology in biology

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Microsystems & Nanoengineering 2022年第5期8卷 1-16页

作者： Yanping Fan Xuan Wang Jiaqi Ren Francis Lin Jiandong Wu School of Optical-Electrical and Computer Engineering University of Shanghai for Science and TechnologyShanghai 200093China Institute of Biomedical and Health Engineering Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China Department of Physics and Astronomy University of ManitobaWinnipegMB R3T 2N2Canada

Acoustofluidic separation of cells and particles is an emerging technology that integrates acoustics and *** the last decade,this technology has attracted significant attention due to its biocompatible,contactless,and labelfree *** has been widely validated in the separation of cells and submicron bioparticles and shows great potential in different biological and biomedical *** review first introduces the theories and mechanisms of acoustofluidic ***,various applications of this technology in the separation of biological particles such as cells,viruses,biomolecules,and exosomes are ***,we discuss the challenges and future prospects of this field.

关键词： fluid separation acoustics

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