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Study of the hottest droplet of fluid through correlations and fluctuations of collective variables

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arXiv 2025年

作者： Samanta, Rupam AGH University of Krakow Faculty of Physics and Applied Computer Science Poland

Collisions of two heavy nuclei at relativistic speeds at the Relativistic Heavy Ion collider (RHIC) at BNL and the Large Hadron Collider (LHC) at CERN, create a state of matter which has a temperature 105 times that of Sun’s core, a size of the order of nuclear radius (femtometer) and which behaves like a perfect fluid with minimal viscosity. This matter under extreme condition, is a medium where the quarks and gluons, normally existing as bound states in hadrons, travel freely with color degrees of freedom, with their interactions governed by Quantum Chromodynamics (QCD). This hot, dense, fluid-like droplet of deconfined state of quarks and gluons is known as the Quark Gluon Plasma (QGP). The QGP medium, surviving for a very short time (10−22 s) with its evolution dynamics described by the relativistic viscous hydrodynamics, creates thousands of particles hitting the detectors at the end. One of the most remarkable features is the collective flow of these particles, serving as a key phenomenon for probing the QGP medium in high energy nuclear collisions. The most peculiar and intriguing characteristics of the collective anisotropic flow, quantified in terms of flow harmonics, is the importance of event-by-event fluctuations, stemming mostly from event-by-event fluctuations in the initial state. In this thesis, we focus on fluctuations and correlations between the collective observables such as mean transverse momentum per particle ([pT]) and harmonic flow coefficients (vn) etc. Specifically, we show that the fluctuations of harmonic flow can be probed by the factorization-breaking coefficients between flow vectors in different pT-bins. Experimental difficulty can be reduced by taking one of the flow vectors momentum averaged. Fluctuations cause a decorrelation between the flow vectors, which can be attributed to equal contributions from the flow magnitude and flow angle decorrelation. We study fluctuations of mean transverse momentum per particle ([pT]) in ultra-ce

关键词： Colliding beam accelerators

Quantum catalysis in cavity quantum electrodynamics

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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

Recent results in polarized proton-proton elastic scattering at STAR 15

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Recent results in polarized proton-proton elastic scattering...

15th Conference on Elastic and Diffractive Scattering, EDS Blois 2013

作者： Adamczyk, Leszek Faculty of Physics and Applied Computer Science AGH-UST Cracow Poland

RHIC is the only spin-polarized proton collider ever built. With a special optics run of ß* ˜ 22 m STAR detector system is suitable for an investigation of the spin dependence of elastic proton-proton scattering. This is a brief summary of measurements of spin asymmetries at the center of mass energy vs = 200 GeV and in the four-momentum transfer squared -t range 0.003 2 by the STAR experiment at RHIC. © Tamás Csörgo, 2012

关键词： Germanium alloys

An Early Detection Model of Prostate Cancer Based on MRI 9

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An Early Detection Model of Prostate Cancer Based on MRI

9th IEEE International Conference on Data science in Cyberspace, DSC 2024

作者： Liu, Yuankun Xing, Lumin Wang, Di Nie, Xin Zhang, Xueyan Wu, Di Liu, Wenjian The First Affiliated Hospital of Shandong First Medical University Shandong Provincial Qianfoshan Hospital Jinan China City University of Macau Faculty of Data Science China Qilu University of Technology Shandong Academy of Sciences Key Laboratory of Computing Power Network and Information Security Ministry of Education Shandong Computer Science Center Jinan China Shandong Fundamental Research Center for Computer Science Shandong Provincial Key Laboratory of Computer Networks Jinan China Chongqing Jianzhu College Chongqing China Shandong Youth University of Political Science School of Information Work Office Jinan China University of Southern Queensland School of Mathematics Physics and Computing QLD Australia

ISBN: (纸本)9798350391367

Prostate cancer is a prevalent form of cancer among men, with a high rate of occurrence but relatively lower mortality compared to other types of cancer. Early detection is crucial because it allows for earlier intervention, potentially preventing progression to more severe stages, and improving patient outcomes. However, human diagnosis is time-consuming and inefficient, an autonomous early detection system is essential for saving lives. To address this challenge, we propose a novel MoE-MRIViT framework that uses advanced machine learning and computer vision techniques to analyze MRI images and identify features indicative of prostate cancer. The system processes the data using a vision transformer to extract precise prostate cancer features from MRI scans, and uses attention mechanisms to focus on significant areas. Through the MoE-MRIViT intervention in two stages, we have achieved superior results compared to the state-of-the-art (SOTA) methods. Experimental results demonstrate that our model achieves an impressive accuracy of 94.84%, outperforming the ResNet-101 and the basic ViT models, which achieve accuracies of 89.4% and 92.31%, respectively. © 2024 IEEE.

关键词： Urology

Atomistic Behavior of Deformed Au Thin Film during the Indentation Process 4

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Atomistic Behavior of Deformed Au Thin Film during the Inden...

4th International Conference on Innovative Research in applied science, Engineering and technology, IRASET 2024

作者： Ou-Khouya, Abdelkarim Mes-Adi, Hassane Taoufiki, Meryem Ibrahim, Imane Ait El Harfouf, Amin Herbazi, Rachid Tahiri, Mohamed Khouribga National School Of Applied Sciences Sultan Moulay Slimane University Process Engineering Computer Science And Mathematics Laboratory Khouribga25000 Morocco Sultan Moulay Slimane University Faculty Of Sciences And Techniques Sustainable Development Laboratory Beni-Mellal Morocco Mohamed V University Laboratory Of Condensed Matter And Interdisciplinary Sciences Cnrst Labeled Research Unit Faculty Of Sciences Departement Of Physics Rabat Morocco University Of Sultan Moulay Slimane Polydisciplinary Faculty Of Khouribga Department Of Physics Khouribga Morocco Tangier Morocco

ISBN: (纸本)9798350309508

In this study, we investigate the mechanical properties of gold (Au) materials using molecular dynamics simulations. In this simulation, the nanoindentation process was performed to analyze the deformation defects and hardness properties of Au under different indentation velocities. The results suggest that the deformation behavior of the Au specimen was affected by different indentation velocities. These findings were confirmed by examining the load-displacement curve, which indicated elastic deformation through the appearance of a linear load-displacement relationship at low indentation velocities. In contrast, plastic deformation was identified by the presence of intensified serrations in the load-displacement curve at higher indentation velocities. Under such conditions, the hardness exhibited minimal variation when the indenter velocity increased from 5 mls to 10 mls. However, a significant increase in hardness was noted when the indentation velocity was further raised to 15 mls. © 2024 IEEE.

关键词： Molecular dynamics

Competing charge density wave phases in YNiC2

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Physical Review B 2025年第19期111卷 195101-195101页

作者： Marta Roman Simone Di Cataldo Berthold Stöger Lisa Reisinger Emilie Morineau Kamil K. Kolincio Herwig Michor Institute of Solid State Physics TU Wien Wiedner Hauptstrasse 8-10 A-1040 Wien Austria Institute of Physics and Applied Computer Science Faculty of Applied Physics and Mathematics Gdańsk University of Technology Narutowicza 11/12 80-233 Gdańsk Poland Dipartimento di Fisica Sapienza University of Rome Piazzale Aldo Moro 5 00185 Rome Italy X-Ray Center TU Wien Getreidemarkt 9 A-1060 Wien Austria Faculty of Applied Physics and Mathematics Gdańsk University of Technology Narutowicza 11/12 80-233 Gdańsk Poland

Charge density wave (CDW) orders in YNiC2 are studied by means of combined experimental and computational techniques. On the experimental side, single crystals grown by the floating-zone method were examined by means of x-ray diffraction, as well as transport and thermal techniques. Density functional theory (DFT) calculations founded on the experimentally determined parent and CDW-modified crystal structures provide details of electronic and phononic structures as well as electron-phonon coupling and resolve changes inflicted upon entering the different CDW phases. Thereby, contrasting effects of subsequently emerging CDW states characterized by incommensurate q1ic and commensurate q2c modulation vectors are revealed. The former state, on-setting below T1ic≃305K, weakly modifies the electronic structure by opening an almost isotropic gap on a minor part of the Fermi surface (FS). The latter phase, which takes over below T2c≃272K has a more pronounced impact on physical properties via a decomposition of larger parts of the FS. These dissimilar behaviors are directly reflected in the electronic transport anisotropy, which is significantly weakened in the q2c-type CDW state. As revealed by our DFT studies, CDW phases are very close in energy and their origin is directly related to the anisotropy of electron-phonon coupling, which is linked to a specific orbital character of related FS sheets. Specific heat and thermal expansion studies reveal a nearly reversible first-order phase transition at around T2c≃272K, where both CDW phases coexist within a T interval of about 10 K.

关键词： Charge density waves

Multiple Defect States Engineering Towards High Thermoelectric Performance in Gete-Based Materials

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SSRN

SSRN 2024年

作者： Parashchuk, Taras Wiendlocha, Bartlomiej Cherniushok, Oleksandr Pryga, Kacper Ciesielski, Kamil Toberer, Eric Wojciechowski, Krzysztof T. AGH University of Krakow Faculty of Materials Science and Ceramics Department of Inorganic Chemistry Thermoelectric Research Laboratory Mickiewicza Ave. 30 Krakow30-059 Poland AGH University of Krakow Faculty of Physics and Applied Computer Science Mickiewicza Ave. 30 Krakow30-059 Poland Colorado School of Mines Department of Physics GoldenCO80401 United States AGH University of Krakow Centre of Energy Laboratory of Thermoelectric Technologies Mickiewicza Ave. 30 Krakow30-059 Poland

GeTe is a promising material for thermoelectric (TE) applications. However, its low Seebeck coefficient and high thermal conductivity in the mid-temperature range of 298-550 K have hindered its widespread use in TE devices. In this work, we show that a combination of resonant-like behavior, Fermi level tuning, and miscibility gap exploration can significantly improve the energy conversion performance of GeTe. The resonant-like hump in GeTe is induced by Ga doping, while Bi provides the optimized carrier concentration and induces band convergence. The synergistic effects of Bi and Ga significantly improve the Seebeck coefficient from 38 µVK-1 for undoped GeTe to over 120 µVK-1 for Bi and Ga-containing materials at 298 K and provide a high power factor over a wide temperature range. Phonon scattering is strengthened by optimizing the microstructure through Pb-induced spinodal decomposition, resulting in a very low lattice thermal conductivity of approximately 0.5 Wm-1K-1 at 600 K for the triple-doped samples. The improved power factor and reduced lattice thermal conductivity resulted in a significant increase in the maximum thermoelectric figure of merit ZT, reaching 2.1 at 600 K for the Ge0.87Pb0.05Bi0.06Ga0.02Te sample. Additionally, the average figure of merit ZTave for this sample achieved an outstanding value of 1.4 for Ge0.87Pb0.05Bi0.06Ga0.02Te at a temperature gradient of 475 K (Tc = 298 K). The developed material shows great potential for use in energy conversion devices, with an estimated energy conversion efficiency exceeding 17%. © 2024, The Authors. All rights reserved.

关键词： Germanium alloys

Deep neural networks for smooth approximation of physics with higher order and continuity B-spline base functions

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arXiv 2022年

作者： Doleglo, Kamil Paszyńska, Anna Paszyński, Maciej Demkowicz, Leszek Institute of Computer Science AGH University of Science and Technology Kraków Poland Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University Kraków Poland Oden Institute for Computational and Engineering Sciences The University of Texas at Austin United States

This paper deals with the following important research question. Traditionally, the neural network employs non-linear activation functions concatenated with linear operators to approximate a given physical phenomenon. They "fill the space" with the concatenations of the activation functions and linear operators and adjust their coefficients to approximate the physical phenomena. We claim that it is better to "fill the space" with linear combinations of smooth higher-order B-splines base functions as employed by isogeometric analysis and utilize the neural networks to adjust the coefficients of linear combinations. In other words, the possibilities of using neural networks for approximating the B-spline base functions' coefficients and by approximating the solution directly are evaluated. Solving differential equations with neural networks has been proposed by Maziar Raissi et al. in 2017 [16] by introducing physics-informed Neural Networks (PINN), which naturally encode underlying physical laws as prior information. Approximation of coefficients using a function as an input leverages the well-known capability of neural networks being universal function approximators [6]. In essence, in the PINN approach the network approximates the value of the given field at a given point. We present an alternative approach, where the physcial quantity is approximated as a linear combination of smooth B-spline basis functions, and the neural network approximates the coefficients of B-splines. This research compares results from the DNN approximating the coefficients of the linear combination of B-spline basis functions, with the DNN approximating the solution directly. We show that our approach is cheaper and more accurate when approximating smooth physical fields. © 2022, CC BY.

关键词： Deep neural networks

Honeycomb anti-dot artificial lattice as a prototypical correlated Dirac fermions system

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arXiv 2023年

作者： Biborski, Andrzej Zegrodnik, Michal Wójcik, Pawel Nowak, Michal P. Academic Centre for Materials and Nanotechnology AGH University of Krakow Al. Mickiewicza 30 Krakow30-059 Poland Faculty of Physics and Applied Computer Science AGH University of Krakow Al. Mickiewicza 30 Krakow30-059 Poland

We study theoretically the electronic properties of the artificial quantum dot honeycomb lattice defined in a two-dimensional electron gas, focusing on the possibility of achieving a regime in which electronic correlations play a dominant role. At first we establish a non-interacting model compatible with recently studied experimentally devices. According to the values of the obtained electron-electron interaction integrals, we postulate that the inclusion of inherent electron-gas self-screening is indispensable to reconstruct the experimental observations. Applying the Thomas-Fermi type of screening, we show that the radius of the anti-dot is crucial to achieve a correlated state in which phenomena like antiferromagentic ordering and interaction-induced insulating state appear. We estimate the conditions for which the electronically correlated state in an artificial honeycomb lattice can be realized. © 2023, CC BY.

关键词： Electron-electron interactions