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IEEE Symposium on Nuclear science (NSS/MIC)

作者： K. Witek M. Caccia W. Kucewicz Ł. Mik Faculty Of Computer Science Electronics And Telecommunications AGH University of Krakow Krakow Poland Department of Science and High Technology Università degli Studi dell'Insubria Como Italy Faculty Of Electronics Telecommunications and Mechatronics University of Applied Sciences in Tarnow Tarnow Poland

ISBN: (数字)9798350388152

ISBN: (纸本)9798350388169

Time-to-Digital Converters (TDCs) play a critical role in numerous high-precision applications across the fields of nuclear science, biomedical engineering, and digital communication systems, including Time-of-Flight (ToF) ranging, Positron Emission Tomography (PET), and All-Digital Phase-Locked Loops (ADPLLs). The demand for flexible architectures providing higher timing precision for an increased number of channels has become a focal point due to the limitations of traditional single-channel TDCs which suffer from low bitrate and resolution. This paper presents the design, implementation and commissioning of a 64-channel TDC using the latest Xilinx Field-Programmable Gate Array (FPGA) technology, aimed at overcoming these challenges and significantly enhancing measurement capabilities. The design is based on a combination of Tapped Delay Line (TDL) and Coarse Counter techniques to optimize both precision and dynamic range. The implementation achieved a remarkable temporal resolution of 18 picoseconds in an exemplary multi-stop implementation providing a sequence of nine time stamps in each cycle. This paper details the system architecture, the implementation challenges and the performance evaluation.

关键词： Performance evaluation Semiconductor device measurement Microwave integrated circuits Image resolution Semiconductor detectors Systems architecture Dynamic range

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Contrastive Learning via Randomly Generated Deep Supervision

Contrastive Learning via Randomly Generated Deep Supervision

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2025 IEEE International Conference on Acoustics, Speech, and Signal Processing, ICASSP 2025

作者： Wang, Shibo Ma, Zili Chan, Ka-Hou Liu, Yue Tong, Tong Gao, Qinquan Zhai, Guangtao Liu, Xiaohong Tan, Tao Faculty of Applied Sciences Macao Polytechnic University China Ischemaview Inc. Menlo ParkCA United States College of Physics and Information Engineering Fuzhou University Fuzhou China John Hopcroft Center for Computer Science Shanghai Jiao Tong University Shanghai China

ISBN: (纸本)9798350368741

Unsupervised visual representation learning has gained significant attention in the computer vision community, driven by recent advancements in contrastive learning. Most existing contrastive learning frameworks rely on instance discrimination as a pretext task, treating each instance as a distinct category. However, this often leads to intra-class collision in a large latent space, compromising the quality of learned representations. To address this issue, we propose a novel contrastive learning method that utilizes randomly generated supervision signals. Our framework incorporates two projection heads: one handles conventional classification tasks, while the other employs a random algorithm to generate fixed-length vectors representing different classes. The second head executes a supervised contrastive learning task based on these vectors, effectively clustering instances of the same class and increasing the separation between different classes. Our method, Contrastive Learning via Randomly Generated Supervision(CLRGS), significantly improves the quality of feature representations across various datasets and achieves state-of-the-art performance in contrastive learning tasks. © 2025 IEEE.

关键词： Class collision Contrastive learning Supervised contrastive learning

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Evaluation and Comparison of Emotionally Evocative Image Augmentation Methods

arXiv

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arXiv 2024年

作者： Ignatowicz, Jan Kutt, Krzysztof Nalepa, Grzegorz J. Jagiellonian Human-Centered AI Lab Mark Kac Center for Complex Systems Research Institute of Applied Computer Science Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Lojasiewicza 11 Kraków30-348 Poland

Experiments in affective computing are based on stimulus datasets that, in the process of standardization, receive metadata describing which emotions each stimulus evokes. In this paper, we explore an approach to creating stimulus datasets for affective computing using generative adversarial networks (GANs). Traditional dataset preparation methods are costly and time consuming, prompting our investigation of alternatives. We conducted experiments with various GAN architectures, including Deep Convolutional GAN, Conditional GAN, Auxiliary Classifier GAN, Progressive Augmentation GAN, and Wasserstein GAN, alongside data augmentation and transfer learning techniques. Our findings highlight promising advances in the generation of emotionally evocative synthetic images, suggesting significant potential for future research and improvements in this domain. © 2024, CC BY.

关键词： Generative adversarial networks

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Quantifying colors at micrometer scale by colorimetric microscopy (C-Microscopy) approach

arXiv

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arXiv 2023年

作者： Jany, Benedykt R. Marian Smoluchowski Institute of Physics Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Lojasiewicza 11 Krakow30348 Poland

The color is the primal property of the objects around us and is direct manifestation of light-matter interactions. The color information is used in many different fields of science, technology and industry to investigate material properties or for identification of concentrations of substances. Usually the color information is used as a global parameter in a macro scale. To quantitatively measure color information in micro scale one needs to use dedicated microscope spectrophotometers or specialized micro-reflectance setups. Here, the Colorimetric Microscopy (C-Microscopy) approach based on digital optical microscopy and a free software is presented. The C-Microscopy approach uses color calibrated image and colorimetric calculations to obtain physically meaningful quantities i. e., dominant wavelength and excitation purity maps at micro level scale. This allows for the discovery of the local color details of samples surfaces. Later, to fully characterize the optical properties, the hyperspectral reflectance data at micro scale (reflectance as a function of wavelength for a each point) are colorimetrically recovered. The C-Microscopy approach was successfully applied to various types of samples i.e., two metamorphic rocks unakite and lapis lazuli, which are mixtures of different minerals;and to the surface of gold 99.999 % pellet, which exhibits different types of surface features. The C-Microscopy approach could be used to quantify the local optical properties changes of various materials at microscale in an accessible way. The approach is freely available as a set of python jupyter notebooks. © 2023, CC BY.

关键词： Color

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Imprints of primordial gravitational waves with non-Bunch-Davies initial states on CMB bispectra

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Physical Review D 2023年第10期108卷 103522-103522页

作者： Shingo Akama Hiroaki W. H. Tahara Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University 30-348 Krakow Poland Department of Physics Rikkyo University Toshima Tokyo 171-8501 Japan

It has been shown that both scalar and tensor modes with non-Bunch-Davies initial states can enhance the amplitudes of the primordial bispectra compared to those with the Bunch-Davies state, especially for wave number modes in a flattened triangle configuration. However, in the case of the non-Bunch-Davies scalar modes, it has also been found that those enhancements in Fourier space are somewhat reduced in bispectra of cosmic microwave background (CMB) fluctuations. In this paper, we show that the enhancement resulting from the tensor modes is partially reduced to a degree differing from that of the scalar modes, which makes the non-Bunch-Davies effects unobservable in gravitational theories with the same quadratic and cubic operators of the tensor perturbations as general relativity. Furthermore, we present examples of gravitational theories yielding enhancements that would potentially be detected through CMB experiments.

关键词： Alternative gravity theories Cosmic microwave background Inflation

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Entanglement wedge method, out-of-time-ordered correlators, and pole skipping

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Physical Review D 2025年第10期111卷 106013-106013页

作者： Banashree Baishya Adrita Chakraborty Nibedita Padhi Department of Physics Indian Institute of Technology Guwahati Assam-781039 India Faculty of Physics and Applied Computer Science AGH University of Krakow al. Adama Mickiewicza 30 30-059 Krakow Poland Department of Physics Indian Institute of Technology Kharagpur Kharagpur 721302 India

We investigate two salient chaotic features, namely Lyapunov exponent and butterfly velocity, for an asymptotically Lifshitz black hole background with arbitrary dynamical critical exponent. These features are computed using three methods: entanglement wedge method, out-of-time-ordered correlator computation, and pole skipping. We present a comparative study where all of these methods yield exactly similar results for the butterfly velocity and Lyapunov exponent. This establishes an equivalence between all three methods for probing chaos in the chosen gravity background. Furthermore, we evaluate the chaos at the classical level by computing the eikonal phase and Lyapunov exponent from the bulk gravity. In the classical approach, we comment on potential limitations while choosing the turning point of the null geodesic in our gravity background. All chaotic properties emerge as nontrivial functions of the anisotropy index. By examining the classical eikonal phase, we uncover different scattering scenarios in the near-horizon and near-boundary regimes. Finally, we remark on a possible classical/quantum correspondence from the analysis of classical eikonal phase shift and Lyapunov exponent.

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Quantum catalysis in cavity quantum electrodynamics

arXiv

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arXiv 2023年

作者： de Oliveira, A. Perarnau-Llobet, Martí Brunner, Nicolas Lipka-Bartosik, Patryk Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Kraków30-348 Poland Department of Applied Physics University of Geneva Geneva1211 Switzerland

Catalysis plays a key role in many scientific areas, most notably in chemistry and biology. Here we present a catalytic process in a paradigmatic quantum optics setup, namely the Jaynes-Cummings model, where an atom interacts with an optical cavity. The atom plays the role of the catalyst, and allows for the deterministic generation of non-classical light in the cavity. Considering a cavity prepared in a "classical" coherent state, and choosing appropriately the atomic state and the interaction time, we obtain an evolution with the following properties. First, the state of the cavity has been modified, and now features non-classicality, as witnessed by sub-Poissonian statistics or Wigner negativity. Second, the process is catalytic, in the sense that the atom is deterministically returned to its initial state exactly, and can be re-used multiple times. What is more, we also show that our findings are robust under dissipation and can be applied to scenarios featuring cavity loss and atomic decay. Finally, we investigate the mechanism of this catalytic process, in particular highlighting the key role of correlations and quantum coherence. © 2023, CC BY.

关键词： Atoms

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EXISTENCE RESULTS FOR SINGULAR FRACTIONAL p-KIRCHHOFF PROBLEMS

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Acta Mathematica Scientia 2022年第3期42卷 1209-1224页

作者： Mingqi XIANG Vicent iu D.RADULESCU Binlin ZHANG College of Science Civil Aviation University of ChinaTianjin 300300China Faculty of Applied Mathematics AGH University of Science and Technologyal.Mickiewicza 3030-059 Krak´owPoland Department of Mathematics University of CraiovaStreet A.I.Cuza No.13200585 CraiovaRomania Institute of Mathematics Physics and MechanicsJadranska 191000 LjubljanaSlovenia College of Mathematics and Systems Science Shandong University of Science and TechnologyQingdao 266590China

This paper is concerned with the existence and multiplicity of solutions for singular Kirchhoff-type problems involving the fractional p-Laplacian *** precisely,we study the following nonlocal problem:{M (∫∫_(R2N)|x|^(α1p)|y|^(α2p)|u(x) − u(y)|^(p)/|x − y|^(N+ps) dxdy)L_(p)^(s)u = |x| ^(β)f(u) in Ω,u = 0 in R^(N) \ Ω,where L_(p)^(s) is the generalized fractional p-Laplacian operator,N≥1,s∈(0,1),α_(1),α_(2),β∈R,Ω■R^(N) is a bounded domain with Lipschitz boundary,and M:R0^(+)→R0^(+),f:Ω→R are continuous ***,we introduce a variational framework for the above ***,the existence of least energy solutions is obtained by using variational methods,provided that the nonlinear term f has(θ_(p-1))-sublinear growth at ***,the existence of infinitely many solutions is obtained by using Krasnoselskii’s genus ***,we obtain the existence and multiplicity of solutions if f has(θ_(p-1))-superlinear growth at *** main features of our paper are that the Kirchhoff function may vanish at zero and the nonlinearity may be singular.

关键词： Fractional Kirchhoff equation singular problems variational and topological methods

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Critical nonlinear aspects of hopping transport for reconfigurable logic in disordered dopant networks

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Physical Review applied 2024年第2期22卷 024063页

作者： Henri Tertilt Jonas Mensing Marlon Becker Wilfred G. van der Wiel Peter A. Bobbert Andreas Heuer Institute for Physical Chemistry Department of Physics NanoElectronics Group Faculty of Electrical Engineering Mathematics and Computer Science MESA+ Institute for Nanotechnology and Center for Brain-Inspired Nano Systems (BRAINS) Department of Applied Physics Center for Computational Energy Research (CCER)

Nonlinear behavior in the hopping transport of interacting charges enables reconfigurable logic in disordered dopant network devices, where voltages applied at control electrodes tune the relation between voltages applied at input electrodes and the current measured at an output electrode. From kinetic Monte Carlo simulations we analyze the critical nonlinear aspects of variable-range hopping transport for realizing Boolean logic gates in these devices on three levels. First, we quantify the occurrence of individual gates for random choices of control voltages. We find that linearly inseparable gates such as the xor gate are less likely to occur than linearly separable gates such as the and gate, despite the fact that the number of different regions in the multidimensional control voltage space for which and or xor gates occur is comparable. Second, we use principal-component analysis to characterize the distribution of the output current vectors for the (00,10,01,11) logic input combinations in terms of eigenvectors and eigenvalues of the output covariance matrix. This allows a simple and direct comparison of the behavior of different simulated devices and a comparison to experimental devices. Third, we quantify the nonlinearity in the distribution of the output current vectors necessary for realizing Boolean functionality by introducing three nonlinearity indicators. The analysis provides a physical interpretation of the effects of changing the hopping distance and temperature and is used in a comparison with data generated by a deep neural network trained on a physical device.

关键词： Carrier dynamics Dynamics of networks Electrical conductivity Fitness Hopping transport Network optimization Optimization problems Temperature

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Percolation thresholds on a triangular lattice for neighborhoods containing sites up to the fifth coordination zone

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Physical Review E 2021年第5期103卷 052107-052107页

作者： Krzysztof Malarz AGH University of Science and Technology Faculty of Physics and Applied Computer Science al. Mickiewicza 30 30-059 Kraków Poland

We determine thresholds pc for random-site percolation on a triangular lattice for all available neighborhoods containing sites from the first to the fifth coordination zones, including their complex combinations. There are 31 distinct neighborhoods. The dependence of the value of the percolation thresholds pc on the coordination number z are tested against various theoretical predictions. The proposed single scalar index ξ=∑iziri2/i (depending on the coordination zone number i, the neighborhood coordination number z, and the square distance r2 to sites in ith coordination zone from the central site) allows one to differentiate among various neighborhoods and relate pc to ξ. The thresholds roughly follow a power law pc∝ξ−γ with γ≈0.710(19).

关键词： Percolation Disordered systems Finite-size scaling

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