506 research outputs found
Dual adaptive training of photonic neural networks
Photonic neural network (PNN) is a remarkable analog artificial intelligence
(AI) accelerator that computes with photons instead of electrons to feature low
latency, high energy efficiency, and high parallelism. However, the existing
training approaches cannot address the extensive accumulation of systematic
errors in large-scale PNNs, resulting in a significant decrease in model
performance in physical systems. Here, we propose dual adaptive training (DAT)
that allows the PNN model to adapt to substantial systematic errors and
preserves its performance during the deployment. By introducing the systematic
error prediction networks with task-similarity joint optimization, DAT achieves
the high similarity mapping between the PNN numerical models and physical
systems and high-accurate gradient calculations during the dual backpropagation
training. We validated the effectiveness of DAT by using diffractive PNNs and
interference-based PNNs on image classification tasks. DAT successfully trained
large-scale PNNs under major systematic errors and preserved the model
classification accuracies comparable to error-free systems. The results further
demonstrated its superior performance over the state-of-the-art in situ
training approaches. DAT provides critical support for constructing large-scale
PNNs to achieve advanced architectures and can be generalized to other types of
AI systems with analog computing errors.Comment: 31 pages, 11 figure
Ethyl 3-(4-methylbenzenesulfonamido)thieno[2,3-b]pyridine-2-carboxylate
The thieno[2,3-b]pyridine ring system of the title compound, C17H16N2O4S2, is essentially planar, the amino and carbonyl groups being nearly coplanar with the heterocyclic ring system. There are two N—H⋯O hydrogen-bonding interactions involving the same N—H donor set and two different acceptors, one in an intramolecular bond helping to fix the molecular geometry and the other defining a dimeric structure around the symmetry centre at (0, , )
Lasiodiplodia sp. ME4-2, an endophytic fungus from the floral parts of Viscum coloratum, produces indole-3-carboxylic acid and other aromatic metabolites
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Stable Hydrazone-Linked Covalent Organic Frameworks Containing O,N,O'-Chelating Sites for Fe(III) Detection in Water.
Two stable crystalline hydrazone-linked covalent organic frameworks (COFs) (Bth-Dha and Bth-Dma) containing functional O,N,O'-chelating sites have been designed and successfully synthesized by the Schiff-base condensation reactions between benzene-1,3,5-tricarbohydrazide (Bth) and 2,5-dihydroxyterephthalaldehyde (Dha) or 2,5-dimethoxyterephthal-aldehyde (Dma), respectively. Bth-Dma exhibits strong fluorescence in the solid state and in an aqueous dispersion, while no fluorescence can be observed for Bth-Dha. Interestingly, the as-synthesized Bth-Dma can be used as a turn-off fluorescence sensor for the Fe(III) ion in aqueous solution with outstanding selectivity and sensitivity. The recognition process can be attributed to the coordination interaction between Fe(III) ion and the O,N,O'-chelating sites in the pore wall of Bth-Dma COF, as verified by X-ray photoelectron spectroscopy and 1H NMR spectroscopy. To the best of our knowledge, this is the first report on the rational design of luminescent COF with predesigned O,N,O'-chelating sites as a fluorescence sensor for highly selective and sensitive metal ion detection. This work may pave the way for designing luminescent COF sensors with functional binding sites for detecting specific metal ions
Interrelated Thermalization and Quantum Criticality in a Lattice Gauge Simulator
Gauge theory and thermalization are both foundations of physics and nowadays
are both topics of essential importance for modern quantum science and
technology. Simulating lattice gauge theories (LGTs) realized recently with
ultracold atoms provides a unique opportunity for carrying out a correlated
study of gauge theory and thermalization in the same setting. Theoretical
studies have shown that an Ising quantum phase transition exists in this
implemented LGT, and quantum thermalization can also signal this phase
transition. Nevertheless, it remains an experimental challenge to accurately
determine the critical point and controllably explore the thermalization
dynamics in the quantum critical regime due to the lack of techniques for
locally manipulating and detecting matter and gauge fields. Here, we report an
experimental investigation of the quantum criticality in the LGT from both
equilibrium and non-equilibrium thermalization perspectives by equipping the
single-site addressing and atom-number-resolved detection into our LGT
simulator. We accurately determine the quantum critical point agreed with the
predicted value. We prepare a state deterministically and study
its thermalization dynamics across the critical point, leading to the
observation that this state thermalizes only in the critical
regime. This result manifests the interplay between quantum many-body scars,
quantum criticality, and symmetry breaking.Comment: 6+4 pages, 4+7 figure
One Small Step for Generative AI, One Giant Leap for AGI: A Complete Survey on ChatGPT in AIGC Era
OpenAI has recently released GPT-4 (a.k.a. ChatGPT plus), which is
demonstrated to be one small step for generative AI (GAI), but one giant leap
for artificial general intelligence (AGI). Since its official release in
November 2022, ChatGPT has quickly attracted numerous users with extensive
media coverage. Such unprecedented attention has also motivated numerous
researchers to investigate ChatGPT from various aspects. According to Google
scholar, there are more than 500 articles with ChatGPT in their titles or
mentioning it in their abstracts. Considering this, a review is urgently
needed, and our work fills this gap. Overall, this work is the first to survey
ChatGPT with a comprehensive review of its underlying technology, applications,
and challenges. Moreover, we present an outlook on how ChatGPT might evolve to
realize general-purpose AIGC (a.k.a. AI-generated content), which will be a
significant milestone for the development of AGI.Comment: A Survey on ChatGPT and GPT-4, 29 pages. Feedback is appreciated
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Demonstration of coherent terahertz transition radiation from relativistic laser-solid interactions
Coherent transition radiation in the terahertz (THz) region with energies of sub-mJ/pulse has been demonstrated by relativistic laser-driven electron beams crossing the solid-vacuum boundary. Targets including mass-limited foils and layered metal-plastic targets are used to verify the radiation mechanism and characterize the radiation properties. Observations of THz emissions as a function of target parameters agree well with the formation-zone and diffraction model of transition radiation. Particle-in-cell simulations also well reproduce the observed characteristics of THz emissions. The present THz transition radiation enables not only a potential tabletop brilliant THz source, but also a novel noninvasive diagnostic for fast electron generation and transport in laser-plasma interactions
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