检索结果-内蒙古大学图书馆

Probing the intergalactic medium during the Epoch of Reionization using 21-cm signal power spectra

学校读者我要写书评

暂无评论

arXiv 2024年

作者： Ghara, R. Shaw, A.K. Zaroubi, S. Ciardi, B. Mellema, G. Koopmans, L.V.E. Acharya, A. Choudhury, M. Giri, S.K. Iliev, I.T. Ma, Q. Mertens, F.G. Kapteyn Astronomical Institute University of Groningen PO Box 800 Groningen9700AV Netherlands Department of Natural Sciences The Open University of Israel 1 University Road PO Box 808 Ra'anana4353701 Israel Haverford College 370 Lancaster Ave HaverfordPA19041 United States Center for Particle Cosmology Department of Physics and Astronomy University of Pennsylvania PhiladelphiaPA19104 United States Department of Computer Science University of Nevada Las VegasNV89154 United States Department of Natural Sciences The Open University of Israel 1 University Road Ra'anana4353701 Israel Max-Planck Institute for Astrophysics Karl-Schwarzschild-Straße 1 Garching85748 Germany The Oskar Klein Centre Department of Astronomy Stockholm University AlbaNova StockholmSE-10691 Sweden Center for Fundamental Physics of the Universe Department of Physics Brown University ProvidenceRI02914 United States Nordita KTH Royal Institute of Technology Stockholm University Hannes Alfvéns väg 12 StockholmSE-106 91 Sweden Astronomy Centre Department of Physics and Astronomy Pevensey II Building University of Sussex BrightonBN1 9QH United Kingdom School of Physics and Electronic Science Guizhou Normal University Guiyang550001 China LERMA Observatoire de Paris PSL Research University CNRS Sorbonne Université ParisF-75014 France

The redshifted 21-cm signal from the epoch of reionization (EoR) directly probes the ionization and thermal states of the intergalactic medium during that period. In particular, the distribution of the ionized regions around the radiating sources during EoR introduces scale-dependent features in the spherically-averaged EoR 21-cm signal power spectrum. The goal is to study these scale-dependent features at different stages of reionization using numerical simulations and build a source model-independent framework to probe the properties of the intergalactic medium using EoR 21-cm signal power spectrum measurements. Under the assumption of high spin temperature, we modelled the redshift evolution of the ratio of EoR 21-cm brightness temperature power spectrum and the corresponding density power spectrum using an ansatz consisting of a set of redshift and scale-independent parameters. This set of eight parameters probes the redshift evolution of the average ionization fraction and the quantities related to the morphology of the ionized regions. We have tested this ansatz on different reionization scenarios generated using different simulation algorithms and found that it is able to recover the redshift evolution of the average neutral fraction within an absolute deviation 0.1. Our framework allows us to interpret 21-cm signal power spectra in terms of parameters related to the state of the IGM. This source model-independent framework is able to efficiently constrain reionization scenarios using multi-redshift power spectrum measurements with ongoing and future radio telescopes such as LOFAR,MWA, HERA, and SKA. This will add independent information regarding the EoR IGM properties. Copyright © 2024, The Authors. All rights reserved.

关键词： Power spectrum

A cryogenic test-mass suspension with flexures operating in compression for third-generation gravitational-wave detectors

学校读者我要写书评

暂无评论

arXiv 2025年

作者： Peña Arellano, Fabián E. Leon, Nelson L. López, Leonardo González DeSalvo, Riccardo Themann, Harry Appavuravther, Esra Zerina Avallone, Guerino Badaracco, Francesca Barton, Mark A. Bertolini, Alessandro Chavez, Christian Damas, Andy Damas, Richard Gallego, Britney Hennes, Eric Iannone, Gerardo Linker, Seth Mondin, Marina Moreno, Claudia Pang, Kevin Selleri, Stefano Soto, Mynor Travasso, Flavio Van-Heijningen, Joris Velez, Fernando Zeoli, Morgane Blvd. Gral. Marcelino García Barragán 1421 Col. Olímpica Jalisco Guadalajara44430 Mexico Institute for Cosmic Ray Research KAGRA Observatory The University of Tokyo 238 Higashi-Mozumi Kamioka-cho Gifu Hida City506-1205 Japan California State University Los Angeles College of Engineering Computer Science and Technology 5151 State University Dr Los AngelesCA90032 United States University of Sannio Department of Engineering Corso Garibaldi 107 BeneventoI-82100 Italy Gruppo Collegato di Salerno Sezione di Napoli via Giovanni Paolo II SA Fisciano Italy California State University Los Angeles Department of Physics and Astronomy 5151 State University Dr Los AngelesCA90032 United States Max Planck Institute for Gravitational Waves Albert Einstein Institute – GEO 600 Callinstraße 38 Hannover30167 Germany Department of Physics "E. R. Caianiello" University of Salerno Via Giovanni Paolo II 132 SA FiscianoI-84084 Italy University of Genova Department of Physics via Dodecaneso 33 Genova16146 Italy Institute for Gravitational Research University of Glasgow GlasgowG12 8QQ United Kingdom Nikhef Science Park 105 Amsterdam1098 XG Netherlands University of Florence Dept. of Information Engineering Via di S. Marta 3 Firenze50139 Italy University of Camerino School of Science and Technology Physics Division Via Madonna delle Carceri 9B MC Camerino62032 Italy Sezione di Perugia - via Pascoli Perugia06125 Italy Vrije Universiteit Amsterdam Department of Physics and Astronomy De Boelelaan 1100 Amsterdam1081 HZ Netherlands UCLouvain Chemin du cyclotron 2 Louvain-la-NeuveB-1348 Belgium Precision Mechatronics Laboratory A&M Dept ULiège Allée de la Découverte 9 LiègeB-4000 Belgium

This paper presents an analysis of the conceptual design of a novel silicon suspension for the cryogenic test-mass mirrors of the low-frequency detector of the Einstein Telescope gravitational-wave observatory. In traditional suspensions, tensional stress is a severe limitation for achieving low thermal noise, safer mechanical margins and high thermal conductance simultaneously. In order to keep the tensional stress sufficiently low, we propose the use of rigid beams with large cross sections, combined with short flexures under compressional load. This configuration takes advantage of the many times higher strength of silicon in compression to respect to its strength in tension. The flexures are mechanically robust and at the same time soft in the working direction, thus producing low suspension thermal noise and, by being short, provide high thermal conductance for cryogenic cooling. The rigid beams, located between the test mass and an intermediate mass, allow the elimination of the recoil mass used conventionally for applying control forces for interferometer lock, and the use of optical anti-springs to reduce the pendulum resonant frequency to further improve the vibration isolation of the test mass. The configuration has the capability to reach a lower mirror operational temperature, which is expected to produce a substantial reduction of the thermal noise in the mirrors of the interferometer. © 2025, CC BY.

关键词： Conceptual design

Corrigendum to “Extraction of notable points from ECG data: A description of a dataset related to 30-s seated and 30-s stand up” [Data in Brief, volume 46 (2023) 108874]

学校读者我要写书评

暂无评论

Data in Brief 2023年 47卷

作者： Rui Pedro Duarte Francisco Alexandre Marinho Eduarda Sofia Bastos Rui João Pinto Pedro Miguel Silva Alice Fermino Hanna Vitalyvna Denysyuk António Jorge Gouveia Norberto Jorge Gonçalves Paulo Jorge Coelho Eftim Zdravevski Petre Lameski Toni Tripunovski Nuno M. Garcia Ivan Miguel Pires Escola de Ciências e Tecnologia Universidade de Trás-Os-Montes e Alto Douro Quinta de Prados Vila Real 5001-801 Portugal Computer Science Department Universidade da Beira Interior Covilhã 6200-001 Portugal Instituto de Telecomunicações Universidade da Beira Interior Covilhã 6200-001 Portugal School of Technology and Management Polytechnic of Leiria Leiria 2411-901 Portugal Institute for Systems Engineering and Computers at Coimbra (INESC Coimbra) DEEC Pólo II Coimbra 3030-290 Portugal Faculty of Computer Science and Engineering University Ss Cyril and Methodius 1000 Skopje North Macedonia Institute of Pathophysiology and Nuclear Medicine University Ss Cyril and Methodius 1000 Skopje North Macedonia

Business forecasting in the light of statistical approaches and machine learning classifiers 3rd

学校读者我要写书评

暂无评论

Business forecasting in the light of statistical approaches ...

3rd International Conference on Advances in Computing and Data sciences, ICACDS 2019

作者： Chakrabarti, Prasun Satpathy, Biswajit Bane, Siddhant Chakrabarti, Tulika Chaudhuri, Narendra S. Siano, Pierluigi Department of Business Administration Sambalpur University SambalpurOdisha768019 India ITM Universe VadodaraGujarat391510 India Department of Computer Science and Engineering ITM Universe VadodaraGujarat391510 India Department of Chemistry Sir Padampat Singhania University Udaipur313601 India Department of Computer Science and Engineering Indian Institute of Technology IndoreMadhya Pradesh453552 India Department of Industrial Engineering University of Salerno Via Giovanni Paolo II 132 FiscianoSA84084 Italy

ISBN: (纸本)9789811399381

The paper focuses a non-conventional approach using Poisson and Binomial distributions for optimum strategic business forecasting. An analysis has been carried out based on profit-loss statistics of consecutive ten years. Relevance of Poisson distribution in business forecasting is shown. Relevance of Binomial distribution in business forecasting is also shown. Curve fitting has been applied to reveal further some discovered facts related to gain analysis. Linear Regression, Exponential, Parabolic, Power function, Logarithmic, polynomial of degree 2 and 4 curves are shown as cases. Novel facts related to business forecasting in the light of machine learning classifiers have been pointed out leading to new directions in the field of research in business analytics. © Springer Nature Singapore Pte Ltd 2019.

关键词： Machine learning

Studies of cosmic-ray solar modulation with the PAMELA experiment 27

学校读者我要写书评

暂无评论

Studies of cosmic-ray solar modulation with the PAMELA exper...

27th European Cosmic Ray Symposium, ECRS 2022

作者： Lenni, A. Boezio, M. Munini, R. Marcelli, N. Menn, W. Potgieter, M.S. Ngobeni, M.D. Adriani, O. Barbarino, G.C. Bazilevskaya, G.A. Bellotti, R. Boezio, M. Bogomolov, E.A. Bongi, M. Bonvicini, V. Bruno, A. Cafagna, F. Campana, D. Carlson, P. Casolino, M. Castellini, G. De Santis, C. Galper, A.M. Koldashov, S.V. Koldobskiy, S. Kvashnin, A.N. Lenni, A. Leonov, A.A. Malakhov, V.V. Marcelli, L. Marcelli, N. Martucci, M. Mayorov, A.G. Menn, W. Merge, M. Mikhailov, V.V. Mocchiutti, E. Monaco, A. Mori, N. Munini, R. Osteria, G. Panico, B. Papini, P. Pearce, M. Picozza, P. Ricci, M. Ricciarini, S.B. Simon, M. Sotgiu, A. Sparvoli, R. Spillantini, P. Stozhkov, Y.I. Vacchi, A. Vannuccini, E. Vasilyev, G.I. Voronov, S.A. Yurkin, Y.T. Zampa, G. Zampa, N. INFN Section of Trieste TriesteI-34127 Italy IFPU - Institute of Fundamental Physics of the Universe TriesteI-34151 Italy Department of Physics University of Siegen SiegenD-57068 Germany Institute for Experimental and Applied Physics University of Kiel KielD-24118 Germany Centre for Space Research North-West University Potchefstroom2520 South Africa University of Florence Department of Physics Sesto Fiorentino FlorenceI-50019 Italy INFN Sezione di Florence Sesto Fiorentino FlorenceI-50019 Italy University of Naples "Federico II " Department of Physics NaplesI-80126 Italy INFN Sezione di Naples NaplesI-80126 Italy Lebedev Physical Institute MoscowRU-119991 Russia University of Bari Department of Physics BariI-70126 Italy INFN Sezione di Bari BariI-70126 Italy INFN Sezione di Trieste TriesteI-34149 Italy Ioffe Physical Technical Institute St. PetersburgRU-194021 Russia KTH Department of Physics The Oskar Klein Centre for Cosmoparticle Physics AlbaNova University Centre StockholmSE-10691 Sweden INFN Sezione di Rome "Tor Vergata" RomeI-00133 Italy RIKEN EUSO team Global Research Cluster Wako-shi Saitama Japan IFAC Sesto Fiorentino FlorenceI-50019 Italy MEPhI National Research Nuclear University MEPhI MoscowRU-115409 Russia University of Trieste Department of Physics TriesteI-34127 Italy University of Rome "Tor Vergata " Department of Physics RomeI-00133 Italy INFN Laboratori Nazionali di Frascati Via Enrico Fermi 40 FrascatiI-00044 Italy University of Siegen Department of Physics SiegenD-57068 Germany Istituto Nazionale di Astrofisica Fosso del cavaliere 100 RomaI-00133 Italy University of Udine Department of Mathematics Computer Science and Physics Via delle Scienze Udine206 Italy

The launch of the satellite-borne PAMELA instrument on the 15th June 2006 opened a new era of high-precision studies of cosmic rays. Due to its low detection energy threshold and its long operation, PAMELA was able to accurately measure the fluxes of several cosmic-ray species over a large energy range and study their time variations below a few tens of GeVs. In this presentation we will review PAMELA results on the time-dependent proton, helium and electron fluxes measured between a few tens of MeV/n and few tens of GeV/n from 2006 to 2014. Moreover, preliminary results of yearly energy spectra of deuterons, helium-3 and helium-4 nuclei below 1 GeV/n will be discussed. These measurements covered a time including the minimum phase of the 23rd solar cycle and the 24th solar maximum including the polarity reversal of the solar magnetic field. The PAMELA measurements have allowed to significantly improve the understanding of the charged-particle propagation through the Heliosphere, the charge-sign effect due to the drift motions of these particles and to calibrate state-of-the-art models of cosmic-ray transport in the Heliosphere. © Copyright owned by the author(s).

关键词： Cosmic rays

Self-Testing of a Single Quantum System: Theory and Experiment

学校读者我要写书评

暂无评论

arXiv 2022年

作者： Hu, Xiao-Min Xie, Yi Arora, Atul Singh Ai, Ming-Zhong Bharti, Kishor Zhang, Jie Wu, Wei Chen, Ping-Xing Cui, Jin-Ming Liu, Bi-Heng Huang, Yun-Feng Li, Chuan-Feng Guo, Guang-Can Roland, Jérémie Cabello, Adán Kwek, Leong-Chuan CAS Key Laboratory of Quantum Information University of Science and Technology of China Hefei230026 China CAS Center For Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Hefei230026 China Department of Physics College of Liberal Arts and Sciences National University of Defense Technology Hunan Changsha410073 China Interdisciplinary Center for Quantum Information National University of Defense Technology Hunan Changsha410073 China Université libre de Bruxelles Belgium Institute of Quantum Information and Matter Department of Computing and Mathematical Sciences California Institute of Technology United States Centre for Quantum Technologies National University of Singapore Singapore Joint Center for Quantum Information and Computer Science Joint Quantum Institute NIST University of Maryland College ParkMD20742 United States Departamento de Física Aplicada II Universidad de Sevilla SevillaE-41012 Spain Instituto Carlos I de Física Teórica y Computacional Universidad de Sevilla SevillaE-41012 Spain MajuLab CNRS-UNS-NUS-NTU International Joint Research Unit UMI 3654 Singapore Singapore National Institute of Education Nanyang Technological University Singapore637616 Singapore

Certifying individual quantum devices with minimal assumptions is crucial for the development of quantum technologies. Here, we investigate how to leverage single-system contextuality to realize self-testing. We develop a robust self-testing protocol based on the simplest contextuality witness for the simplest contextual quantum system, the Klyachko-Can-Binicioğlu-Shumovsky (KCBS) inequality for the qutrit. We establish a lower bound on the fidelity of the state and the measurements (to an ideal configuration) as a function of the value of the witness under a pragmatic assumption on the measurements we call the KCBS orthogonality condition. We apply the method in an experiment with randomly chosen measurements on a single trapped 40Ca+ and near-perfect detection efficiency. The observed statistics allow us to self-test the system and provide the first experimental demonstration of quantum self-testing of a single system. Further, we quantify and report that deviations from our assumptions are minimal, an aspect previously overlooked by contextuality experiments. Copyright © 2022, The Authors. All rights reserved.

关键词： Quantum optics

PRS-Net: Planar reflective symmetry detection net for 3D models

学校读者我要写书评

暂无评论

arXiv 2019年

作者： Gao, Lin Zhang, Ling-Xiao Meng, Hsien-Yu Ren, Yi-Hui Lai, Yu-Kun Kobbelt, Leif Institute of Computing Technology Chinese Academy of Sciences Beijing China University of Maryland College ParkMD United States Visual Computing Group School of Computer Science and Informatics Cardiff University Wales United Kingdom Institute for Computer Graphics and Multimedia RWTH Aachen University Aachen Germany

In geometry processing, symmetry is a universal type of high-level structural information of 3D models and benefits many geometry processing tasks including shape segmentation, alignment, matching, and completion. Thus it is an important problem to analyze various symmetry forms of 3D shapes. Planar reflective symmetry is the most fundamental one. Traditional methods based on spatial sampling can be time-consuming and may not be able to identify all the symmetry planes. In this paper, we present a novel learning framework to automatically discover global planar reflective symmetry of a 3D shape. Our framework trains an unsupervised 3D convolutional neural network to extract global model features and then outputs possible global symmetry parameters, where input shapes are represented using voxels. We introduce a dedicated symmetry distance loss along with a regularization loss to avoid generating duplicated symmetry planes. Our network can also identify generalized cylinders by predicting their rotation axes. We further provide a method to remove invalid and duplicated planes and axes. We demonstrate that our method is able to produce reliable and accurate results. Our neural network based method is hundreds of times faster than the state-of-the-art methods, which are based on sampling. Our method is also robust even with noisy or incomplete input surfaces. Copyright © 2019, The Authors. All rights reserved.

关键词： Geometry

Significant-loophole-free test of Kochen-Specker contextuality using two species of atomic-ions

学校读者我要写书评

暂无评论

arXiv 2021年

作者： Wang, Pengfei Zhang, Junhua Luan, Chun-Yang Um, Mark Wang, Ye Qiao, Mu Xie, Tian Zhang, Jing-Ning Cabello, Adán Kim, Kihwan State Key Laboratory of Low Dimensional Quantum Physics Department of Physics Tsinghua University Beijing100084 China Beijing Academy of Quantum Information Sciences Beijing100193 China Shenzhen Institute for Quantum Science and Engineering Southern University of Science and Technology Shenzhen518055 China Department of Electrical and Computer Engineering Duke University DurhamNC27708 United States Kavli Nanoscience Institute Thomas J. Watson Sr. Laboratory of Applied Physics California Institute of Technology PasadenaCA91125 United States Departamento de Física Aplicada II Universidad de Sevilla SevillaE-41012 Spain Instituto Carlos I de Física Teórica y Computacional Universidad de Sevilla SevillaE-41012 Spain Frontier Science Center for Quantum Information Beijing100084 China

Quantum measurements cannot be thought of as revealing preexisting results, even when they do not disturb any other measurement in the same trial. This feature is called contextuality and is crucial for the quantum advantage in computing. Here, we report the first observation of quantum contextuality simultaneously free of the detection, sharpness and compatibility loopholes. The detection and sharpness loopholes are closed by adopting a hybrid two-ion system and highly efficient fluorescence measurements offering a detection efficiency of 100% and a measurement repeatability > 98%. The compatibility loophole is closed by targeting correlations between observables for two different ions in a Paul trap, a 171Yb+ ion and a 138Ba+ ion, chosen so measurements on each ion use different operation laser wavelengths, fluorescence wavelengths, and detectors. The experimental results show a violation of the bound for the most adversarial noncontextual models and open a new way to certify quantum *** Codes 81P13(Primary) 78A37(Secondary) © 2021, CC BY.

关键词： Ions

Retraction notice to “New impressive performances for the analytical solutions to the (1+1)-dimensional van der-waals gas system against its numerical solutions” [Res. Phys. 51 (2023) 106667]

学校读者我要写书评

暂无评论

Results in Physics 2025年 72卷

作者： Emad H.M. Zahran Hijaz Ahmad Sameh Askar Dilber Uzun Ozsahin Departments of Basic Science Benha University Faculty of Engineering Shubra Egypt Section of Mathematics International Telematic University Uninettuno Corso Vittorio Emanuele II 39 00186 Roma Italy Near East University Operational Research Center in Healthcare Nicosia PC: 99138 TRNC Mersin 10 Turkey Department of Computer Science and Mathematics Lebanese American University Beirut Lebanon Department of Statistics and Operations Research College of Science King Saud University P.O. Box 2455 Riyadh 11451 Saudi Arabia Department of Medical Diagnostic Imaging College of Health Science University of Sharjah Sharjah United Arab Emirates Research Institute for Medical and Health Sciences University of Sharjah Sharjah United Arab Emirates