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Spin decoherence and off-resonance behavior of radiofrequency-driven spin rotations in storage rings

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arXiv 2023年

作者： Nikolaev, N.N. Rathmann, F. Slim, J. Andres, A. Hejny, V. Nass, A. Kacharava, A. Lenisa, P. Pretz, J. Saleev, A. Shmakova, V. Soltner, H. Abusaif, F. Aggarwal, A. Aksentev, A. Alberdi, B. Barion, L. Bekman, I. Beyß, M. Böhme, C. Breitkreutz, B. Canale, N. Ciullo, G. Dymov, S. Fröhlich, N.-O. Gebel, R. Gaisser, M. Grigoryev, K. Grzonka, D. Hetzel, J. Javakhishvili, O. Kamerdzhiev, V. Karanth, S. Keshelashvili, I. Kononov, A. Laihem, K. Lehrach, A. Lomidze, N. Lorentz, B. Macharashvili, G. Magiera, A. McHedlishvili, D. Melnikov, A. Müller, F. Pesce, A. Poncza, V. Prasuhn, D. Shergelashvili, D. Shurkhno, N. Siddique, S. Silenko, A. Stassen, S. Stephenson, E.J. Ströher, H. Tabidze, M. Tagliente, G. Valdau, Y. Vitz, M. Wagner, T. Wirzba, A. Wrońska, A. Wüstner, P. Żurek, M. L.D. Landau Institute for Theoretical Physics Chernogolovka142432 Russia Institut für Kernphysik Forschungszentrum Jülich Jülich52425 Germany III. Physikalisches Institut B RWTH Aachen University Aachen52056 Germany University of Ferrara Istituto Nazionale di Fisica Nucleare Ferrara44100 Italy Zentralinstitut für Engineering Elektronik und Analytik Forschungszentrum Jülich Jülich52425 Germany Marian Smoluchowski Institute of Physics Jagiellonian University Cracow30348 Poland Institute for Nuclear Research Russian Academy of Sciences Moscow117312 Russia Department of Electrical and Computer Engineering Agricultural University of Georgia Tbilisi0159 Georgia High Energy Physics Institute Tbilisi State University Tbilisi0186 Georgia GSI Helmholtzzentrum für Schwerionenforschung Darmstadt64291 Germany Bogoliubov Laboratory of Theoretical Physics Joint Institute for Nuclear Research Dubna141980 Russia Indiana University Department of Physics BloomingtonIN47405 United States Istituto Nazionale di Fisica Nucleare sez. Bari Bari70125 Italy Institute for Advanced Simulation Forschungszentrum Jülich Jülich52425 Germany

Radiofrequency-driven resonant spin rotators are routinely used as standard instruments in polarization experiments in particle and nuclear physics. Maintaining the continuous exact parametric spin-resonance condition of the equality of the spin rotator and the spin precession frequency during operation constitutes one of the challenges. We present a detailed analytic description of the impact of detuning the exact spin resonance on the vertical and the in-plane precessing components of the polarization. An important part of the formalism presented here is the consideration of experimentally relevant spin-decoherence effects. We discuss applications of the developed formalism to the interpretation of the experimental data on the novel pilot bunch approach to control the spin-resonance condition during the operation of the radiofrequency-driven Wien filter that is used as a spin rotator in the first direct deuteron electric dipole moment measurement at COSY. We emphasize the potential importance of the hitherto unexplored phase of the envelope of the horizontal polarization as an indicator of the stability of the radiofrequency-driven spin rotations in storage rings. The work presented here serves as a satellite publication to the work published concurrently on the proof of principle experiment about the so-called pilot bunch approach that was developed to provide co-magnetometry for the deuteron electric dipole moment experiment at COSY. © 2023, CC BY.

关键词： Electric dipole moments

Hadoop perfect file: A fast access container for small files with direct in disc metadata access

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arXiv 2019年

作者： Tchaye-Kondi, Jude Zhai, Yanlong Lin, Kwei-Jay Zhu, Liehuang Tao, Wenjun Yang, Kai School of Computer Science Beijing Institute of Technology Beijing100081 China Department of Electrical Engineering and Computer Science University of California IrvineCA92697 United States Science and Technology on Special System Simulation Laboratory Beijing Simulation Center Beijing China

Storing and processing massive small files is one of the major challenges for the Hadoop Distributed File System (HDFS). In order to provide fast data access, the NameNode (NN) in HDFS maintains the metadata of all files in its main-memory. Hadoop performs well with a small number of large files that require relatively little metadata in the NN’s memory. But for a large number of small files, Hadoop has problems such as NN memory overload caused by the huge metadata size of these small files. We present a new type of archive file, Hadoop Perfect File (HPF), to solve HDFS’s small files problem by merging small files into a large file on HDFS. Existing archive files offer limited functionality and have poor performance when accessing a file in the merged file due to the fact that during metadata lookup it is necessary to read and process the entire index file(s). In contrast, HPF file can directly access the metadata of a particular file from its index file without having to process it entirely. The HPF index system uses two hash functions: file’s metadata are distributed through index files by using a dynamic hash function and, for each index file, we build an order preserving perfect hash function that preserves the position of each file’s metadata in the index file. The HPF design will only read the part of the index file that contains the metadata of the searched file during its access. HPF file also supports the file appending functionality after its creation. Our experiments show that HPF can be more than 40% faster file’s access from the original HDFS. If we don’t consider the caching effect, HPF’s file access is around 179% faster than MapFile and 11294% faster than HAR file. If we consider caching effect, HPF is around 35% faster than MapFile and 105% faster than HAR file. Copyright © 2019, The Authors. All rights reserved.

关键词： File organization

Pilot bunch and co-magnetometry of polarized particles stored in a ring

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arXiv 2023年

作者： Slim, J. Rathmann, F. Andres, A. Hejny, V. Nass, A. Kacharava, A. Lenisa, P. Nikolaev, N.N. Pretz, J. Saleev, A. Shmakova, V. Soltner, H. Abusaif, F. Aggarwal, A. Aksentev, A. Alberdi, B. Barion, L. Bekman, I. Beyß, M. Böhme, C. Breitkreutz, B. Canale, N. Ciullo, G. Dymov, S. Fröhlich, N.-O. Gebel, R. Gaisser, M. Grigoryev, K. Grzonka, D. Hetzel, J. Javakhishvili, O. Kamerdzhiev, V. Karanth, S. Keshelashvili, I. Kononov, A. Laihem, K. Lehrach, A. Lomidze, N. Lorentz, B. Macharashvili, G. Magiera, A. McHedlishvili, D. Melnikov, A. Müller, F. Pesce, A. Poncza, V. Prasuhn, D. Shergelashvili, D. Shurkhno, N. Siddique, S. Silenko, A. Stassen, S. Stephenson, E.J. Ströher, H. Tabidze, M. Tagliente, G. Valdau, Y. Vitz, M. Wagner, T. Wirzba, A. Wrońska, A. Wüstner, P. Żurek, M. III. Physikalisches Institut B RWTH Aachen University Aachen52056 Germany Institut für Kernphysik Forschungszentrum Jülich Jülich52425 Germany University of Ferrara Istituto Nazionale di Fisica Nucleare Ferrara44100 Italy L.D. Landau Institute for Theoretical Physics Chernogolovka142432 Russia Zentralinstitut für Engineering Elektronik und Analytik Forschungszentrum Jülich Jülich52425 Germany Marian Smoluchowski Institute of Physics Jagiellonian University Cracow30348 Poland Institute for Nuclear Research Russian Academy of Sciences Moscow117312 Russia Department of Electrical and Computer Engineering Agricultural University of Georgia Tbilisi0159 Georgia High Energy Physics Institute Tbilisi State University Tbilisi0186 Georgia GSI Helmholtzzentrum für Schwerionenforschung Darmstadt64291 Germany Bogoliubov Laboratory of Theoretical Physics Joint Institute for Nuclear Research Dubna141980 Russia Indiana University Department of Physics BloomingtonIN47405 United States Istituto Nazionale di Fisica Nucleare sez. Bari Bari70125 Italy Institute for Advanced Simulation Forschungszentrum Jülich Jülich52425 Germany

In polarization experiments at storage rings, one of the challenges is to maintain the spin-resonance condition of a radio-frequency spin rotator with the spin-precessions of the orbiting particles. Time-dependent variations of the magnetic fields of ring elements lead to unwanted variations of the spin precession frequency. We report here on a solution to this problem by shielding (or masking) one of the bunches stored in the ring from the high-frequency fields of the spin rotator, so that the masked pilot bunch acts as a co-magnetometer for the other signal bunch, tracking fluctuations in the ring on a time scale of about one second. While the new method was developed primarily for searches of electric dipole moments of charged particles, it may have far-reaching implications for future spin physics facilities, such as the EIC and NICA. © 2023, CC BY.

关键词： Charged particles

Reachability as a Unifying Framework for Computing Helicopter Safe Operating Conditions and Autonomous Emergency Landing ⁎

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IFAC-PapersOnLine 2020年第2期53卷 9282-9287页

作者： Matthew R. Kirchner Eddie Ball Jacques Hoffler Don Gaublomme Image and Signal Processing Branch Code D5J1000 Naval Air Warfare Center Weapons Division China Lake CA USA Electrical and Computer Engineering Department University of California Santa Barbara CA 93106 USA Flight Vehicle Modeling and Simulation Branch Naval Air Warfare Center Aircraft Division Patuxent River MD USA

We present a numeric method to compute the safe operating flight conditions for a helicopter such that we can ensure a safe landing in the event of a partial or total engine failure. The unsafe operating region is the complement of the backwards reachable tube, which can be found as the sub-zero level set of the viscosity solution of a Hamilton-Jacobi (HJ) equation. Traditionally, numerical methods used to solve the HJ equation rely on a discrete grid of the solution space and exhibit exponential scaling with dimension, which is problematic for the high-fidelity dynamics models required for accurate helicopter modeling. We avoid the use of spatial grids by formulating a trajectory optimization problem, where the solution at each initial condition can be computed in a computationally efficient manner. The proposed method is shown to compute an autonomous landing trajectory from any operating condition, even in non-cruise flight conditions.

关键词： Reachability Autorotation Optimal Control

Numerical Analysis of Electrical Discharge in DC Switches Under External Circuit Parameter Variations

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Numerical Analysis of Electrical Discharge in DC Switches Un...

International Conference on Electric Power Equipment - Switching Technology (ICEPE-ST)

作者： Kyung Sik Seo Myung Ki Baek Il Han Park School of Electronic and Electrical Engineering Sungkyunkwan University Suwon Korea Computer Simulation-Based Design Department Korea Electrotechnology Research Institute Changwon Korea

This paper presents a self-consistent and multiphysics discharge model to analyze the characteristics of the electric discharge generated in a current-switching system. Switching discharge is numerically analyzed by a simplified one-dimensional model using the finite element method. Several simulations with different external resistances were performed to analyze the effect of the external circuit parameter on electric discharge.

关键词： Discharges (electric) Cathodes Mathematical model Plasma temperature Atmospheric modeling Switches

Modeling Interface Charge Traps in Junctionless FETs, Including Temperature Effects

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arXiv 2019年

作者： Rassekh, Amin Jazaeri, Farzan Fathipour, Morteza Sallese, Jean-Michel Ecole Polytechnique Fédérale de Lausanne Switzerland device simulation and modeling Laboratory department of electrical and computer engineering University of Tehran Iran

In this paper, an analytical predictive model of interface charge traps in symmetric long channel double-gate junctionless transistors is proposed based on a charge-based model. Interface charge traps arising from the exposure to chemicals, high-energy ionizing radiation or aging mechanism could degrade the charge-voltage characteristics. The model is predictive in a range of temperature from 77K to 400K. The validity of the approach is confirmed by extensive comparisons with numerical TCAD simulations in all regions of operation from deep depletion to accumulation and linear to saturation. Copyright © 2019, The Authors. All rights reserved.

关键词： Ionizing radiation

Ductile deformation mechanism in semiconductor α-Ag_(2)S

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npj Computational Materials 2018年第1期4卷 289-294页

作者： Guodong Li Qi An Sergey I.Morozov Bo Duan William A.Goddard III Qingjie Zhang Pengcheng Zhai G.Jeffrey Snyder State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology430070 WuhanChina Department of Materials Science and Engineering Northwestern UniversityEvanstonIL 60208USA Department of Chemical and Materials Engineering University of Nevada RenoRenoNV 89557USA Department of Computer Simulation and Nanotechnology South Ural State UniversityChelyabinsk 454080Russia Materials and Process Simulation Center California Institute of TechnologyPasadenaCA 91125USA

Inorganic semiconductor α-Ag_(2)S exhibits a metal-like ductile behavior at room temperature,but the origin of this high ductility has not been fully explored *** on density function theory simulations on the intrinsic mechanical properties of α-Ag_(2)S,its underlying ductile mechanism is attributed to the following three factors:(i)the low ideal shear strength and multiple slip pathways under pressure,(ii)easy movement of Ag–S octagon framework without breaking Ag−S bonds,and(iii)a metallic Ag−Ag bond forms which suppresses the Ag-S frameworks from slipping and holds them *** easy slip pathways(or easy rearrangement of atoms without breaking bonds)in α-Ag_(2)S provide insight into the understanding of the plastic deformation mechanism of ductile semiconductor materials,which is beneficial for devising and developing flexible semiconductor materials and electronic devices.

关键词： deformation ductile ductility

Selective excitation of a three-dimensionally oriented single plasmonic dipole

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Photonics Research 2019年第6期7卷 693-698页

作者： FAJUN XIAO GUANGLIN WANG XUETAO GAN WUYUN SHANG SHIYIN CAO WEIREN ZHU TING MEI MALIN PREMARATNE JIANLIN ZHAO MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions and Shaanxi Key Laboratory of Optical Information Technology School of Science Northwestern Polytechnical University Xi'an 710129 China Department of Electronic Engineering Shanghai Jiao Tong University Shanghai 200240 China Advanced Computing and Simulation Laboratory (AXL) Department of Electrical and Computer Systems Engineering Monash University Clayton VIC 3800 Australia

We experimentally demonstrate a scheme to deterministically excite a three-dimensionally oriented electric dipole in a single Au nanosphere by using a tightly focused radially polarized beam whose focal field possesses polarization states along three-dimensional(3D) orientations owing to the spatial overlap between longitudinal and radial electric field components. Experiment observations indicate that the orientation of an excited dipole moment gradually changes from out-of-plane to in-plane when the nanosphere is moved away from the beam center, which is reconfirmed by full-wave simulations. Moreover, rigorous calculation based on Mie theory reveals that a reduced effective ambient permittivity accompanies the rotation of the dipole moment, leading to a blue-shifted and narrowed resonance peak. We envision that our results could find applications in detecting the 3D orientation of isolated molecules and benefit the fine manipulation of light–matter interactions at the single-molecule level.

关键词： Selective excitation plasmonic dipole

Power Characterization of Memory Intensive Applications: Analysis and Implications 1st

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Power Characterization of Memory Intensive Applications: Ana...

1st International Symposium on Benchmarking, Measuring, and Optimization, Bench 2018

作者： Qiu, Yeliang Jiang, Congfeng Fan, Tiantian Wang, Yumei Zhang, Liangbin Wan, Jian Shi, Weisong Key Laboratory of Complex Systems Modeling and Simulation Ministry of Education Hangzhou Dianzi University Hangzhou310037 China School of Computer Science and Technology Hangzhou Dianzi University Hangzhou310037 China College of Big Data and Software Engineering Zhejiang Wanli University Ningbo China School of Information and Electronic Engineering Zhejiang University of Science and Technology Hangzhou310023 China Department of Computer Science Wayne State University DetroitMI48202 United States

ISBN: (纸本)9783030328122

DRAM is a significant source of server power consumption especially when the server runs memory intensive applications. Current power aware scheduling assumes that DRAM is as energy proportional as other components. However, the non-energy proportionality of DRAM significantly affects the power and energy consumption of the whole server system when running memory intensive applications. Thus good knowledge of server power characterization under memory intensive workloads can help better workload placement with power reduction. In this paper, we investigate the power characteristics of memory intensive applications on real rack servers of different generations. Through comprehensive analysis we find that (1) Server power consumption changes with workload intensity and concurrent execution threads. However, fully utilized memory systems are not the most energy efficient. (2) Powered memory modules of installed memory capacity, i.e. the memory capacity per processor core has significant impact on the application’s performance and server power consumption even if the memory system is not fully utilized. (3) Memory utilization is not always a good indicator for server power consumption when it is running memory intensive applications. Our experiments show that hardware configuration, workload types, as well as concurrently running threads have significant impact on a server’s energy efficiency when running memory intensive applications. Our findings presented in this paper provide useful insights and guidance to system designers, as well as data center operators for energy efficiency aware job scheduling and power reductions. © 2019, Springer Nature Switzerland AG.

关键词： Energy efficiency