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arXiv 2023年

作者： Lipka-Bartosik, Patryk Chubb, Christopher T. Renes, Joseph M. Tomamichel, Marco Korzekwa, Kamil Department of Applied Physics University of Geneva Geneva1211 Switzerland Institute for Theoretical Physics ETH Zurich Zürich8093 Switzerland Department of Electrical and Computer Engineering National University of Singapore Singapore117583 Singapore Centre for Quantum Technologies National University of Singapore Singapore117543 Singapore Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Kraków30-348 Poland

We address the problem of exact and approximate transformation of quantum dichotomies in the asymptotic regime, i.e., the existence of a quantum channel E mapping (Equation presented) into (Equation presented) with an error ϵn (measured by trace distance) and (Equation presented) into (Equation presented) exactly, for a large number n. We derive second-order asymptotic expressions for the optimal transformation rate Rn in the small, moderate, and large deviation error regimes, as well as the zero-error regime, for an arbitrary pair (ρ1,σ1) of initial states and a commuting pair (ρ2,σ2) of final states. We also prove that for σ1 and σ2 given by thermal Gibbs states, the derived optimal transformation rates in the first three regimes can be attained by thermal operations. This allows us, for the first time, to study the second-order asymptotics of thermodynamic state interconversion with fully general initial states that may have coherence between different energy eigenspaces. Thus, we discuss the optimal performance of thermodynamic protocols with coherent inputs and describe three novel resonance phenomena allowing one to significantly reduce transformation errors induced by finite-size effects. What is more, our result on quantum dichotomies can also be used to obtain, up to second-order asymptotic terms, optimal conversion rates between pure bipartite entangled states under local operations and classical communication. Copyright © 2023, The Authors. All rights reserved.

关键词： Thermodynamics

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Investigation of Novel Preclinical Total Body PET Designed With J-PET Technology: A Simulation Study

arXiv

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arXiv 2024年

作者： Dadgar, M. Parzych, S. Ardebili, F. Tayefi Baran, J. Chug, N. Curceanu, C. Czerwiński, E. Dulski, K. Eliyan, K. Gajos, A. Hiesmayr, B.C. Kacprzak, K. Kaplon, L. Klimaszewski, K. Konieczka, P. Korcyl, G. Kozik, T. Krzemien, W. Kumar, D. Niedzwiecki, S. Panek, D. del Rio, E. Perez Raczynski, L. Sharma, S. Shivani Shopa, R.Y. Skurzok, M. Ardebili, K. Tayefi Vandenberghe, S. Wislicki, W. Stepien, E.L. Moskal, P. The Faculty of Physics Astronomy and Applied Computer Science Total Body Jagiellonian-PET Laboratory Jagiellonian University Kraków31-007 Poland The Faculty of Physics Astronomy and Applied Computer Science Total Body Jagiellonian-PET Laboratory Jagiellonian University Kraków31-007 Poland INFN Laboratori Nazionali di Frascati Frascati00044 Italy The Faculty of Physics University of Vienna Vienna1010 Austria The Department of Complex Systems National Centre for Nuclear Research Otwock-Świerk 05-400 Poland High Energy Physics Division National Centre for Nuclear Research Otwock-Świerk 05-400 Poland The Department of Electronics and Information Systems MEDISIP Ghent University-IBiTech Ghent9000 Belgium

The growing interest in human-grade total body positron emission tomography (PET) systems has also application in small animal research. Due to the existing limitations in human-based studies involving drug development and novel treatment monitoring, animal-based research became a necessary step for testing and protocol preparation. In this simulation-based study two unconventional, cost-effective small animal total body PET scanners (for mouse and rat studies) have been investigated in order to inspect their feasibility for preclinical research. They were designed with the novel technology explored by the Jagiellonian-PET (J-PET) Collaboration. Two main PET characteristics: sensitivity and spatial resolution were mainly inspected to evaluate their performance. Moreover, the impact of the scintillator dimension and time-of-flight on the latter parameter was examined in order to design the most efficient tomographs. The presented results show that for mouse TB J-PET the achievable system sensitivity is equal to 2.35% and volumetric spatial resolution to 9.46 ± 0.54 mm3, while for rat TB J-PET they are equal to 2.6% and 14.11 ± 0.80 mm3, respectively. Furthermore, it was shown that the designed tomographs are almost parallax-free systems, hence, they resolve the problem of the acceptance criterion tradeoff between enhancing spatial resolution and reducing sensitivity. © 2024, CC BY.

关键词： Positrons

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Stochastic kinetics under combined action of two noise sources

arXiv

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arXiv 2022年

作者： Pogorzelec, Przemyslaw Dybiec, Bartlomiej Doctoral School of Exact and Natural Sciences Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Lojasiewicza 11 Kraków30-348 Poland Institute of Theoretical Physics Mark Kac Center for Complex Systems Research Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Lojasiewicza 11 Kraków30-348 Poland

We are exploring two archetypal noise induced escape scenarios: escape from a finite interval and from the positive half-line under the action of the mixture of Lévy and Gaussian white noises in the overdamped regime, for the random acceleration process and higher order processes. In the case of escape from finite intervals, mixture of noises can result in the change of value of the mean first passage time in comparison to the action of each noise separately. At the same time, for the random acceleration process on the (positive) half-line, over the wide range of parameters, the exponent characterizing the power-law decay of the survival probability is equal to the one characterizing the decay of the survival probability under action of the (pure) Lévy noise. There is a transient region, width of which increases with stability index α, when the exponent decreases from the one for Lévy noise to the one corresponding to the Gaussian white noise driving. © 2022, CC BY.

关键词： White noise

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Fuzzy Logic-Based Control of a Battery Energy Storage System to Mitigate Frequency Excursions in the Cuban Power System Caused by Electric Arc Furnaces

SSRN

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SSRN 2024年

作者： Domínguez, Julio Espinosa Serban, Ioan Breffe, Orlys Ernesto Torres Transilvania University of Brasov Department of Electrical Engineering and Applied Physics Faculty of Electrical Engineering and Computer Science Eroilor 29 Brasov500036 Romania Technological University of Havana Department of Electrical Engineering Faculty of Electrical Engineering Street 114 # 11901 e/ Ciclovía and Rotonda Havana19390 Cuba

This paper proposes an adaptive control for a battery energy storage system (BESS) using a fuzzy logic controller (FLC), specially designed to operate in parallel with an electric arc furnace (EAF) in the Cuban power system. The BESS control system was developed with considerations for the characteristics of the Cuban power system, the typical power demand profile of the EAF, and the lifetime of batteries. The primary goal is to mitigate the frequency excursions that currently occur during EAF operation, enabling the furnace to complete the smelting process without restrictions. Furthermore, the system aims to reduce battery overloading, thereby enhancing their lifetime. For this purpose, the BESS active power is managed by an adaptive compensator, governed by the FLC. Based on information coming from all the three components involved - power system frequency, furnace state and battery usage rate, the proposed FLC generates an optimum output to adjust the BESS behaviour. The performance of the proposed system was evaluated through simulations and experimental tests. The results demonstrate that using adaptive control applied to BESS can be an effective solution for steel plants connected to weakly-regulated power systems, such as the current Cuban power system. © 2024, The Authors. All rights reserved.

关键词： Fuzzy logic

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Estimation of River Water Surface Elevation Using UAV Photogrammetry and Machine Learning

arXiv

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arXiv 2023年

作者： Szostak, Radoslaw Pietroń, Marcin Wachniew, Przemyslaw Zimnoch, Miroslaw Ćwiąkala, Pawel AGH University of Science and Technology Faculty of Physics and Applied Computer Science ul. Reymonta 19 building D-10 Kraków Poland AGH University of Science and Technology Faculty of Computer Science Electronics and Telecommunications al. Mickiewicza 30 building D-17 Krakow Poland AGH University of Science and Technology Faculty of Geo-Data Science Geodesy and Environmental Engineering al. Mickiewicza 30 building C-4 Krakow Poland

Unmanned aerial vehicle (UAV) photogrammetry allows for the creation of orthophotos and digital surface models (DSMs) of a terrain. However, DSMs of water bodies mapped with this technique reveal water surface distortions, preventing the use of photogrammetric data for accurate determination of water surface elevation (WSE). Firstly, we propose a new solution in which a deep learning (DL) convolutional neural network (CNN) is used as a WSE estimator from photogrammetric DSMs and orthophotos. Second, we improved the previously known "water-edge" method by filtering the outliers using a forward-backwards exponential weighted moving average (FBEWMA). An additional improvement in these two methods was achieved by performing a linear regression of the WSE values against chainage. Furthermore, the solutions estimate the uncertainty of the predictions, which allows the evaluation of the model credibility when the ground-truth values are unknown. To our knowledge, this is the first approach in which DL was used for this task. A brand new machine learning data set has been created for the purpose of this work. It was collected on a small lowland river in winter and summer conditions. It consists of 322 samples, each corresponding to a 10 by 10 meter area of the river channel and adjacent land. Each data set sample contains orthophoto and DSM arrays as input, along with a single ground-truth WSE value as output. The data set was supplemented with data collected by other researchers that compared the state-of-the-art methods for determining WSE using an UAV. This makes these additional data an excellent benchmark to compare the method developed with existing ones. The results of the DL solution were verified using the reliable k-fold cross-validation method, in which samples from a single survey campaign were excluded from training and used as a validation subset. This provided an in-depth examination of the model's ability to perform on previously unseen data. The WSE RMSE va

关键词： Antennas

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Nagaoka spin-valley ordering in silicene quantum dots

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Physical Review B 2021年第12期103卷 125306-125306页

作者： Piotr Jurkowski Bartłomiej Szafran AGH University of Science and Technology Faculty of Physics and Applied Computer Science al. Mickiewicza 30 30-059 Kraków Poland

We study a cluster of quantum dots defined within silicene that hosts confined electron states with spin and valley degrees of freedom. Atomistic tight-binding and continuum Dirac approximations are applied for a few-electron system in the quest for spontaneous valley polarization driven by interdot tunneling and an electron-electron interaction, i.e., a valley counterpart of itinerant Nagaoka ferromagnetic ordering recently identified in a GaAs square cluster of quantum dots with three excess electrons [J. P. Dehollain et al., Nature (London) 579, 528 (2020)]. We find that for a Hamiltonian without intrinsic spin-orbit coupling the valley polarization in the ground state can be observed in a range of interdot spacings provided that the spin of the system is frozen by an external magnetic field. The intervalley scattering effects are negligible for a cluster geometry that supports the valley-polarized ground state. In the presence of a strong intrinsic spin-orbit coupling that is characteristic to silicene, no external magnetic field is necessary for the observation of a ground state that is polarized in both the spin and valley. The effective magnetic field due to the spin-orbit interaction produces a perfect anticorrelation of the spin and valley isospin components in the low-energy spectrum. Experimental detection of spin-valley ground-state polarization by a charge response to a potential variation is discussed.

关键词： Magnetic order Spin-orbit coupling Valleytronics Double quantum dots Graphene Quantum dots Silicene Two-dimensional electron system Exact diagonalization Tight-binding model

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Annular confinement for electrons on liquid helium

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Physical Review B 2021年第23期104卷 235402-235402页

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

We discuss the annular electron confinement on the liquid helium surface induced by a submerged tubular electrode. For a shallow liquid layer the resulting potential has a minimum off the symmetry axis of the electrode. The ground-state angular momentum transitions that are driven by the external magnetic field can be resolved when the confinement radii in the first and second Rydberg subbands of the vertical quantization are different, e.g., for submersion depth of the tube comparable to its radius. Then, discontinuities in the main microwave absorption line appear with the period that corresponds to the subsequent magnetic flux quanta passing across the area within the ground-state confinement radius.

关键词： Aharonov-Bohm effect Electronic excitation & ionization Electronic structure Mesoscopics Surface & interfacial phenomena Surface states 0-dimensional systems 2-dimensional systems Quantum dots Quantum rings Two-dimensional electron gas Finite-element method Liquid helium cooling Microwave techniques

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Non-homotopic Loops with a Bounded Number of Pairwise Intersections 29th

Non-homotopic Loops with a Bounded Number of Pairwise Int...

引用

29th International Symposium on Graph Drawing and Network Visualization, GD 2021

作者： Blažej, Václav Opler, Michal Šileikis, Matas Valtr, Pavel Faculty of Information Technology Czech Technical University in Prague Prague Czech Republic Computer Science Institute Charles University Prague Czech Republic Czech Academy of Sciences Institute of Computer Science Prague Czech Republic Department of Applied Mathematics Faculty of Mathematics and Physics Charles University Prague Czech Republic

ISBN: (纸本)9783030929305

Let Vn be a set of n points in the plane and let x∉ Vn. An x-loop is a continuous closed curve not containing any point of Vn. We say that two x-loops are non-homotopic if they cannot be transformed continuously into each other without passing through a point of Vn. For n= 2, we give an upper bound eO(k) on the maximum size of a family of pairwise non-homotopic x-loops such that every loop has fewer than k self-intersections and any two loops have fewer than k intersections. The exponent O(k) is asymptotically tight. The previous upper bound 2(2k)4 was proved by Pach et al. [6]. We prove the above result by proving the asymptotic upper bound eO(k) for a similar problem when x∈ Vn, and by proving a close relation between the two problems. © 2021, Springer Nature Switzerland AG.

关键词： Drawing (graphics)

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Comment on “Phase transition in a network model of social balance with Glauber dynamics”

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Physical Review E 2021年第6期103卷 066301-066301页

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

In a recent work [R. Shojaei et al., Phys. Rev. E 100, 022303 (2019)] the authors calculate numerically the critical temperature Tc of the balanced-imbalanced phase transition in a fully connected graph. According to their findings, Tc decreases with the number of nodes N. Here we calculate the same critical temperature using the heat-bath algorithm. We show that Tc increases with N as Nγ, with γ close to 0.5 or 1.0. This value depends on the initial fraction of positive bonds.

关键词： Social dynamics Social networks

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Towards the Heider balance: Cellular automaton with a global neighborhood

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Physical Review E 2021年第2期104卷 024307-024307页

作者： Malgorzata J. Krawczyk Krzysztof Kulakowski Zdzislaw Burda AGH University of Science and Technology Faculty of Physics and Applied Computer Science al. Mickiewicza 30 30-059 Kraków Poland

We study a simple deterministic map that leads a fully connected network to the Heider balance. The map is realized by an algorithm that updates all links synchronously in a way depending on the state of the entire network. We observe that the probability of reaching a balanced state increases with the system size N. Jammed states become less frequent for larger N. The algorithm generates also limit cycles, mostly of length 2, but also of length 3, 4, 6, 12, or 14. We give a simple argument to estimate the mean size of basins of attraction of balanced states, and we discuss the symmetries of the system including the automorphism group as well as gauge invariance of triad configurations. We argue that both symmetries play an essential role in the occurrence of cycles observed in the synchronous dynamics realized by the algorithm.

关键词： Cycles Evolving networks

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