- 标题
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gauge models: Towards quantum simulations of the Schwinger-Weyl QED
摘要： We study the ground-state properties of a class of Zn lattice gauge theories in 1 + 1 dimensions, in which the gauge fields are coupled to spinless fermionic matter. These models, stemming from discrete representations of the Weyl commutator for the U(1) group, preserve the unitary character of the minimal coupling and have, therefore, the property of formally approximating lattice quantum electrodynamics in one spatial dimension in the large-n limit. The numerical study of such approximated theories is important to determine their effectiveness in reproducing the main features and phenomenology of the target theory, in view of implementations of cold-atom quantum simulators of QED. In this paper, we study the cases n = 2 ÷ 8 by means of a DMRG code that exactly implements Gauss’s law. We perform a careful scaling analysis and show that, in absence of a background field, all Zn models exhibit a phase transition which falls in the Ising universality class, with spontaneous symmetry breaking of the CP symmetry. We then perform the large-n limit and find that the asymptotic values of the critical parameters approach the ones obtained for the known phase transition of the zero-charge sector of the massive Schwinger model, which occurs at negative mass.
关键词： phase transition,Ising universality class,CP symmetry,Zn lattice gauge theories,cold-atom quantum simulators,DMRG code,quantum electrodynamics
更新于2025-09-23 15:21:21
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Coumarin Caged Compounds of 1-Naphthaleneacetic Acid as Light-Responsive Controlled-Release Plant Root Stimulators
摘要： Six coumarin caged compounds of NAA comprising different substituents on the coumarin moiety were synthesized and evaluated for their photo-physical and chemical properties as light-responsive controlled-release plant root stimulators. The 1H-NMR and HPLC techniques were used to verify the release of NAA from the caged compounds. After irradiation at 365 nm, the caged compounds exhibited the fastest release rate at t1/2 of 6.7 days and the slowest release rate at t1/2 of 73.7 days. Caged compounds at high concentration (10-5 M and 10-6 M) significantly stimulate secondary root germination while free NAA at the same level is toxic and leads to inhibition of secondary root germination. Cytotoxicity of the caged compounds against Fibroblasts and Vero cells were evaluated and the results suggested that at 10-5 – 10-6 M, caged compounds exhibit no significant cytotoxic to the cells. Thus, the caged compounds of NAA in this study can be of great benefits as efficient agrochemicals.
关键词： Photoremovable protecting groups,Agrochemicals,Coumarin caged compounds,Photocontrolled-release plant growth regulators,Plant root simulators,1-Naphthaleneacetic acid
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Spectral Sensitization With Dyes Of Heterophase Microsystems "Nucleus a?? Silver Halide Shell"
摘要： This task force paper summarizes the state-of-the-art real-time digital simulation concepts and technologies that are used for the analysis, design, and testing of the electric power system and its apparatus. This paper highlights the main building blocks of the real-time simulator, i.e., hardware, software, input-output systems, modeling, and solution techniques, interfacing capabilities to external hardware and various applications. It covers the most commonly used real-time digital simulators in both industry and academia. A comprehensive list of the real-time simulators is provided in a tabular review. The objective of this paper is to summarize salient features of various real-time simulators, so that the reader can benefit from understanding the relevant technologies and their applications, which will be presented in a separate paper.
关键词： simulation,digital simulators,power engineering,hardware-in-the-loop (HIL),power system transient simulation,real-time systems,Digital real-time simulation (DRTS)
更新于2025-09-19 17:13:59
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[IEEE OCEANS 2019 MTS/IEEE SEATTLE - Seattle, WA, USA (2019.10.27-2019.10.31)] OCEANS 2019 MTS/IEEE SEATTLE - Distributed Acoustic Sensing measurement by using seafloor optical fiber cable system off Sanriku for seismic observation
摘要： The energy management system (EMS) at utility control centers collects real-time measurements to monitor current grid conditions. The EMS is also a suite of analytics that synthesizes these measurements to provide the grid operator with information to identify current problems and potential future problems. With evolving grid influences, such as growth of variable renewable generation resources, distributed generation, microgrids, demand response (DR), and customer engagement programs, managing the grid is becoming more challenging. Concurrently, however, there are nascent new technologies and advances in grid management schemes that will improve the ability to manage the future grid operations. These technologies include new subsecond synchrophasor measurements and analytics, advances in high-performance computing, visualization platforms, digital relays, cloud computing, and so on. Advances in grid management schemes include adding more intelligence at the substation and distribution systems, as well as microgrids and wide-area monitoring systems. One key initiative is to develop a predict-and-mitigate paradigm enabling anticipatory vision and timely decisions to mitigate potential problems before they spread to the rest of the grid. The word ‘‘proactive’’ means ‘‘to act now in anticipation of future problems.’’ Proactive grid management opportunities and solutions are described in this paper.
关键词： visualization,simulators,FACTS,phasor measurement units (PMUs),Energy management systems (EMSs),synchrophasors,wide-area monitoring system (WAMS)
更新于2025-09-16 10:30:52
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Challenges in the pre-normative characterization of bifacial photovoltaic modules
摘要： Bifacial photovoltaic (PV) technology is receiving growing interest on the market, with several companies commercializing bifacial modules alongside their conventional products, with various c-Si structures, such as PERC, PERT, HIT, IBC, etc. Current-voltage characterization of bifacial PV modules at Standard Test Conditions (STC) is challenging, as it requires an extension of the definition of STC that includes the spectral and total irradiance on the rear side of the module. Indoor characterization in principle allows the most accurate control of these quantities: the simplest procedure involves measurements of each side of the bifacial module at a time with a single light source, while carefully keeping the other side in the dark. This procedure requires attention to minimize unintended contributions to the module power from the non-illuminated side, which is associated to the reflected irradiance from surroundings, to the optical properties of the module, and to the geometrical disposition of the cells. This work revises the pre-normative activity that has led to the draft standard IEC 60904-1-2 (due for publication in 2018) and focuses on the new norm in what concerns indoor measurement with a single-source simulator. It illustrates the metrological challenges in the selection of the non-reflective material behind the non-illuminated side, and their impact to the electrical characterization of bifacial modules.
关键词： Electrical characterization,Standard Test Conditions,Solar simulators,Bifacial photovoltaic modules
更新于2025-09-12 10:27:22
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AIP Conference Proceedings [AIP Publishing 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Fes, Morocco (25–27 March 2019)] 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Toward a simple and accurate spectral balance monitoring of solar simulators for multijunction solar cells
摘要： Currently, solar simulators demand component solar cells, also named isotypes, in order to equilibrate their spectrum and match the required norm. Each architecture of cell needs a specific set of isotypes and each one of them need calibration in order to assess the incident power coming from the solar simulator in its spectral range. In this article, pseudo-isotypes are proposed in order to ease the spectral balance of new architectures of multijunction solar cells (MJSC). Pseudo-isotypes are silicon and germanium photodiodes filtered with filters reproducing the cut-on and the cut-off of each MJSC subcell. The use of pseudo-isotypes requires the development of a simple and accurate calibration in order to obtain the constants associated with these references without sending it to a certified laboratory. An indoor calibration method is described and its accuracy is assessed. IV characteristics of 3J MJSC under a solar simulator are carried out with different sets of references: i) isotypes calibrated outdoor, ii) isotypes calibrated indoor, and iii) pseudo-isotypes calibrated indoor.
关键词： indoor calibration,solar simulators,multijunction solar cells,pseudo-isotypes,spectral balance
更新于2025-09-11 14:15:04
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<i>Ab initio</i> exact diagonalization simulation of the Nagaoka transition in quantum dots
摘要： Recent progress of quantum simulators provides insight into the fundamental problems of strongly correlated systems. To adequately assess the accuracy of these simulators, the precise modeling of the many-body physics, with accurate model parameters, is crucially important. In this paper, we employed an ab initio exact diagonalization framework to compute the correlated physics of a few electrons in artificial potentials. We apply this approach to a quantum-dot system and study the magnetism of the correlated electrons, obtaining good agreement with recent experimental measurements in a plaquette. Through control of dot potentials and separation, including geometric manipulation of tunneling, we examine the Nagaoka transition and determine the robustness of the ferromagnetic state. While the Nagaoka theorem considers only a single-band Hubbard model, in this work we perform extensive ab initio calculations that include realistic multiorbital conditions in which the level splitting is smaller than the interactions. This simulation complements the experiments and provides insight into the formation of ferromagnetism in correlated systems. More generally, our calculation sets the stage for further theoretical analysis of analog quantum simulators at a quantitative level.
关键词： Nagaoka transition,ab initio exact diagonalization,ferromagnetic state,quantum simulators,strongly correlated systems,quantum-dot system
更新于2025-09-11 14:15:04
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[ASME ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference - Quebec City, Quebec, Canada (Sunday 26 August 2018)] Volume 1B: 38th Computers and Information in Engineering Conference - High Degree of Freedom Hand Pose Tracking Using Limited Strain Sensing and Optical Training
摘要： The ability to track human operators’ hand usage when working in production plants and factories is critically important for developing realistic digital factory simulators as well as manufacturing process control. We propose an instrumented glove with only a few strain gauge sensors and a micro-controller that continuously tracks and records the hand configuration during actual use. At the heart of our approach is a trainable system that can predict the fourteen joint angles in the hand using only a small set of strain sensors. First, ten strain gauges are placed at the various joints in the hand to optimize the sensor layout using the English letters in the American Sign Language as a benchmark for assessment. Next, the best sensor configurations for three through ten strain gauges are computed using a support vector machine classifier. Following the layout optimization, our approach learns a mapping between the sensor readouts to the actual joint angles optically captured using a Leap Motion system. Three regression methods including linear, quadratic and neural regression are then used to train the mapping between the strain gauge data and the corresponding joint angles. The final proposed model involves four strain gauges mapped to the fourteen joint angles using a two-layer feed-forward neural network.
关键词： digital factory simulators,neural regression,strain gauge sensors,hand pose tracking,Leap Motion
更新于2025-09-09 09:28:46