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arXiv 2020年

作者： Choi, Steve K. Hasselfield, Matthew Ho, Shuay-Pwu Patty Koopman, Brian Lungu, Marius Abitbol, Maximilian H. Addison, Graeme E. Ade, Peter A.R. Aiola, Simone Alonso, David Amiri, Mandana Amodeo, Stefania Angile, Elio Austermann, Jason E. Baildon, Taylor Battaglia, Nick Beall, James A. Bean, Rachel Becker, Daniel T. Bond, J. Richard Bruno, Sarah Marie Calabrese, Erminia Calafut, Victoria Campusano, Luis E. Carrero, Felipe Chesmore, Grace E. Cho, Hsiao-Mei Clark, Susan E. Cothard, Nicholas F. Crichton, Devin Crowley, Kevin T. Darwish, Omar Datta, Rahul Denison, Edward V. Devlin, Mark J. Duell, Cody J. Duff, Shannon M. Duivenvoorden, Adriaan J. Dunkley, Jo Dünner, Rolando Essinger-Hileman, Thomas Fankhanel, Max Ferraro, Simone Fox, Anna E. Fuzia, Brittany Gallardo, Patricio A. Gluscevic, Vera Golec, Joseph E. Grace, Emily Gralla, Megan Guan, Yilun Hall, Kirsten Halpern, Mark Han, Dongwon Hargrave, Peter Henderson, Shawn Hensley, Brandon Hill, J. Colin Hilton, Gene C. Hilton, Matt Hincks, Adam D. Hložek, Renée Hubmayr, Johannes Huffenberger, Kevin M. Hughes, John P. Infante, Leopoldo Irwin, Kent Jackson, Rebecca Klein, Jeff Knowles, Kenda Kosowsky, Arthur Lakey, Victoria Li, Dale Li, Yaqiong Li, Zack Lokken, Martine Louis, Thibaut MacInnis, Amanda Madhavacheril, Mathew Maldonado, Felipe Mallaby-Kay, Maya Marsden, Danica Maurin, Loïc McMahon, Jeff Menanteau, Felipe Moodley, Kavilan Morton, Tim Naess, Sigurd Namikawa, Toshiya Nati, Federico Newburgh, Laura Nibarger, John P. Nicola, Andrina Niemack, Michael D. Nolta, Michael R. Orlowski-Sherer, John Page, Lyman A. Pappas, Christine G. Partridge, Bruce Phakathi, Phumlani Prince, Heather Puddu, Roberto Qu, Frank J. Rivera, Jesus Robertson, Naomi Rojas, Felipe Salatino, Maria Schaan, Emmanuel Schillaci, Alessandro Schmitt, Benjamin L. Sehgal, Neelima Sherwin, Blake D. Sierra, Carlos Sievers, Jon Sifon, Cristobal Sikhosana, Precious Simon, Sara Spergel, David N. Staggs, Suzanne T. Stevens, Jason Storer, Emilie Sunder, Dhaneshwar D. Switzer, Eric R. Thorne, Ben Thornton, Robe Department of Physics Cornell University IthacaNY14853 United States Department of Astronomy Cornell University IthacaNY14853 United States Joseph Henry Laboratories of Physics Jadwin Hall Princeton University PrincetonNJ08544 United States Center for Computational Astrophysics Flatiron Institute 162 5th Avenue New YorkNY10010 United States Department of Astronomy and Astrophysics The Pennsylvania State University University ParkPA16802 United States Institute for Gravitation and the Cosmos The Pennsylvania State University University ParkPA16802 United States Department of Physics Yale University 217 Prospect St New HavenCT06511 United States Department of Physics and Astronomy University of Pennsylvania 209 South 33rd Street PhiladelphiaPA19104 United States Department of Physics University of Oxford Keble Road OxfordOX1 3RH United Kingdom Dept. of Physics and Astronomy The Johns Hopkins University 3400 N. Charles St. BaltimoreMD21218-2686 United States School of Physics and Astronomy Cardiff University The Parade Wales CardiffCF24 3AA United Kingdom Department of Physics and Astronomy University of British Columbia VancouverBCV6T 1Z4 Canada NIST Quantum Devices Group 325 Broadway Mailcode 817.03 BoulderCO80305 United States Department of Physics University of Michigan Ann Arbor48103 United States Canadian Institute for Theoretical Astrophysics University of Toronto TorontoONM5S 3H8 Canada Universidad de Chile Dept Astronomía Casilla Santiago36-D Chile Sociedad Radiosky Asesorías de Ingeniería Limitada Camino a Toconao 145-A Ayllu de Solor San Pedro de Atacama Chile Department of Physics University of Chicago ChicagoIL60637 United States SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo ParkCA94025 United States Institute for Advanced Study 1 Einstein Dr PrincetonNJ08540 United States Department of Applied and Engineering Physics Cornell University IthacaNY14853 United States Astrophysics Res

We present the temperature and polarization angular power spectra of the CMB measured by the Atacama Cosmology Telescope (ACT) from 5400 deg2 of the 2013-2016 survey, which covers >15000 deg2 at 98 and 150 GHz. For this analysis we adopt a blinding strategy to help avoid confirmation bias and, related to this, show numerous checks for systematic error done before unblinding. Using the likelihood for the cosmological analysis we constrain secondary sources of anisotropy and foreground emission, and derive a "CMB-only" spectrum that extends to = 4000. At large angular scales, foreground emission at 150 GHz is ∼1% of TT and EE within our selected regions and consistent with that found by Planck. Using the same likelihood, we obtain the cosmological parameters for ΛCDM for the ACT data alone with a prior on the optical depth of τ = 0.065 ± 0.015. ΛCDM is a good fit. The best-fit model has a reduced χ2 of 1.07 (PTE = 0.07) with H0 = 67.9 ± 1.5 km/s/Mpc. We show that the lensing BB signal is consistent with ΛCDM and limit the celestial EB polarization angle to ψP = −0.07◦ ± 0.09◦. We directly cross correlate ACT with Planck and observe generally good agreement but with some discrepancies in TE. All data on which this analysis is based will be publicly released. Copyright © 2020, The Authors. All rights reserved.

关键词： Cosmology

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A new search direction of DFP-CG method for solving unconstrained optimization problems

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AIP Conference Proceedings 2018年第1期1974卷

作者： Wan Farah Hanan Wan Osman Mohd Asrul Hery Ibrahim Mustafa Mamat 1Faculty of Computer Media & Technology Management Tati University College 24000 Kemaman Terengganu Malaysia 3Department of Computational and Applied Mathematics Universiti Sultan Zainal Abidin Campus Tembila 22200 Besut Terengganu Malaysia 2Faculty of Entrepreneurship and Business Universiti Malaysia Kelantan 16100 Kota Bharu Kelantan Malaysia

The conjugate gradient (CG) and Davidon, Fletcher and Powell (DFP) method are both well known solvers for solving unconstrained optimization problems. In this paper, we proposed a new hybrid DFP-CG method and compared with the ordinary DFP method in terms of number of iteration and CPU times. Numerical results show that the new algorithm is more efficient compared to the ordinary DFP method and proven to posses both sufficient descent and global convergence properties.

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The Atacama Cosmology Telescope: DR4 maps and cosmological parameters

arXiv

引用

arXiv 2020年

作者： Aiola, Simone Calabrese, Erminia Maurin, Loïc Naess, Sigurd Schmitt, Benjamin L. Abitbol, Maximilian H. Addison, Graeme E. Ade, Peter A.R. Alonso, David Amiri, Mandana Amodeo, Stefania Angile, Elio Austermann, Jason E. Baildon, Taylor Battaglia, Nick Beall, James A. Bean, Rachel Becker, Daniel T. Bond, J. Richard Bruno, Sarah Marie Calafut, Victoria Campusano, Luis E. Carrero, Felipe Chesmore, Grace E. Cho, Hsiao-Mei Choi, Steve K. Clark, Susan E. Cothard, Nicholas F. Crichton, Devin Crowley, Kevin T. Darwish, Omar Datta, Rahul Denison, Edward V. Devlin, Mark J. Duell, Cody J. Duff, Shannon M. Duivenvoorden, Adriaan J. Dunkley, Jo Dünner, Rolando Essinger-Hileman, Thomas Fankhanel, Max Ferraro, Simone Fox, Anna E. Fuzia, Brittany Gallardo, Patricio A. Gluscevic, Vera Golec, Joseph E. Grace, Emily Gralla, Megan Guan, Yilun Hall, Kirsten Halpern, Mark Han, Dongwon Hargrave, Peter Hasselfield, Matthew Helton, Jakob M. Henderson, Shawn Hensley, Brandon Hill, J. Colin Hilton, Gene C. Hilton, Matt Hincks, Adam D. Hložek, Renée Ho, Shuay-Pwu Patty Hubmayr, Johannes Huffenberger, Kevin M. Hughes, John P. Infante, Leopoldo Irwin, Kent Jackson, Rebecca Klein, Jeff Knowles, Kenda Koopman, Brian Kosowsky, Arthur Lakey, Victoria Li, Dale Li, Yaqiong Li, Zack Lokken, Martine Louis, Thibaut Lungu, Marius MacInnis, Amanda Madhavacheril, Mathew Maldonado, Felipe Mallaby-Kay, Maya Marsden, Danica McMahon, Jeff Menanteau, Felipe Moodley, Kavilan Morton, Tim Namikawa, Toshiya Nati, Federico Newburgh, Laura Nibarger, John P. Nicola, Andrina Niemack, Michael D. Nolta, Michael R. Orlowski-Sherer, John Page, Lyman A. Pappas, Christine G. Partridge, Bruce Phakathi, Phumlani Pisano, Giampaolo Prince, Heather Puddu, Roberto Qu, Frank J. Rivera, Jesus Robertson, Naomi Rojas, Felipe Salatino, Maria Schaan, Emmanuel Schillaci, Alessandro Sehgal, Neelima Sherwin, Blake D. Sierra, Carlos Sievers, Jon Sifon, Cristobal Sikhosana, Precious Simon, Sara Spergel, David N. Staggs, Suzanne T. Stevens, Jason Storer, Emilie Sunder, Dhaneshwar D. Switzer, Center for Computational Astrophysics Flatiron Institute 162 5th Avenue New YorkNY10010 United States Joseph Henry Laboratories of Physics Jadwin Hall Princeton University PrincetonNJ08544 United States School of Physics and Astronomy Cardiff University The Parade Wales CardiffCF24 3AA United Kingdom Université Paris-Saclay CNRS Institut d'astrophysique spatiale Orsay 91405 France Instituto de Astrofísica Centro de Astro-Ingeniería Facultad de Fìsica Pontificia Universidad Católica de Chile Av. Vicuña Mackenna 4860 Macul Santiago7820436 Chile Department of Physics and Astronomy University of Pennsylvania 209 South 33rd Street PhiladelphiaPA19104 United States Department of Physics University of Oxford Keble Road OxfordOX1 3RH United Kingdom Dept. of Physics and Astronomy The Johns Hopkins University 3400 N. Charles St. BaltimoreMD21218-2686 United States Department of Physics and Astronomy University of British Columbia VancouverBCV6T 1Z4 Canada Department of Astronomy Cornell University IthacaNY14853 United States NIST Quantum Devices Group 325 Broadway Mailcode 817.03 BoulderCO80305 United States Department of Physics University of Michigan Ann Arbor48103 United States Canadian Institute for Theoretical Astrophysics University of Toronto TorontoONM5S 3H8 Canada Universidad de Chile Dept Astronomía Casilla Santiago36-D Chile Sociedad Radiosky Asesorías de Ingeniería Limitada Camino a Toconao 145-A Ayllu de Solor San Pedro de Atacama Chile Department of Physics University of Chicago ChicagoIL60637 United States SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo ParkCA94025 United States Department of Physics Cornell University IthacaNY14853 United States Institute for Advanced Study 1 Einstein Dr PrincetonNJ08540 United States Department of Applied and Engineering Physics Cornell University IthacaNY14853 United States Astrophysics Research Centre School of Mathematics Statistics and Computer Scie

We present new arcminute-resolution maps of the Cosmic Microwave Background temperature and polarization anisotropy from the Atacama Cosmology Telescope, using data taken from 2013-2016 at 98 and 150 GHz. The maps cover more than 17,000 deg2, the deepest 600 deg2 with noise levels below 10µK-arcmin. We use the power spectrum derived from almost 6,000 deg2 of these maps to constrain cosmology. The ACT data enable a measurement of the angular scale of features in both the divergence-like polarization and the temperature anisotropy, tracing both the velocity and density at last-scattering. From these one can derive the distance to the last-scattering surface and thus infer the local expansion rate, H0. By combining ACT data with large-scale information from WMAP we measure H0 = 67.6±1.1 km/s/Mpc, at 68% confidence, in excellent agreement with the independently-measured Planck satellite estimate (from ACT alone we find H0 = 67.9 ±1.5 km/s/Mpc). The ΛCDM model provides a good fit to the ACT data, and we find no evidence for deviations: both the spatial curvature, and the departure from the standard lensing signal in the spectrum, are zero to within 1σ;the number of relativistic species, the primordial Helium fraction, and the running of the spectral index are consistent with ΛCDM predictions to within 1.5-2.2σ. We compare ACT, WMAP, and Planck at the parameter level and find good consistency;we investigate how the constraints on the correlated spectral index and baryon density parameters readjust when adding CMB large-scale information that ACT does not measure. The DR4 products presented here will be publicly released on the NASA Legacy Archive for Microwave Background Data Analysis. Copyright © 2020, The Authors. All rights reserved.

关键词： Cosmology

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Constraints on dark photon dark matter using data from LIGO’s and Virgo’s third observing run

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Physical Review D 2022年第6期105卷 063030-063030页

作者： R. Abbott T. D. Abbott F. Acernese K. Ackley C. Adams N. Adhikari R. X. Adhikari V. B. Adya C. Affeldt D. Agarwal M. Agathos K. Agatsuma N. Aggarwal O. D. Aguiar L. Aiello A. Ain P. Ajith T. Akutsu S. Albanesi A. Allocca P. A. Altin A. Amato C. Anand S. Anand A. Ananyeva S. B. Anderson W. G. Anderson M. Ando T. Andrade N. Andres T. Andrić S. V. Angelova S. Ansoldi J. M. Antelis S. Antier S. Appert Koji Arai Koya Arai Y. Arai S. Araki A. Araya M. C. Araya J. S. Areeda M. Arène N. Aritomi N. Arnaud S. M. Aronson K. G. Arun H. Asada Y. Asali G. Ashton Y. Aso M. Assiduo S. M. Aston P. Astone F. Aubin C. Austin S. Babak F. Badaracco M. K. M. Bader C. Badger S. Bae Y. Bae A. M. Baer S. Bagnasco Y. Bai L. Baiotti J. Baird R. Bajpai M. Ball G. Ballardin S. W. Ballmer A. Balsamo G. Baltus S. Banagiri D. Bankar J. C. Barayoga C. Barbieri B. C. Barish D. Barker P. Barneo F. Barone B. Barr L. Barsotti M. Barsuglia D. Barta J. Bartlett M. A. Barton I. Bartos R. Bassiri A. Basti M. Bawaj J. C. Bayley A. C. Baylor M. Bazzan B. Bécsy V. M. Bedakihale M. Bejger I. Belahcene V. Benedetto D. Beniwal T. F. Bennett J. D. Bentley M. BenYaala F. Bergamin B. K. Berger S. Bernuzzi D. Bersanetti A. Bertolini J. Betzwieser D. Beveridge R. Bhandare U. Bhardwaj D. Bhattacharjee S. Bhaumik I. A. Bilenko G. Billingsley S. Bini R. Birney O. Birnholtz S. Biscans M. Bischi S. Biscoveanu A. Bisht B. Biswas M. Bitossi M.-A. Bizouard J. K. Blackburn C. D. Blair D. G. Blair R. M. Blair F. Bobba N. Bode M. Boer G. Bogaert M. Boldrini L. D. Bonavena F. Bondu E. Bonilla R. Bonnand P. Booker B. A. Boom R. Bork V. Boschi N. Bose S. Bose V. Bossilkov V. Boudart Y. Bouffanais A. Bozzi C. Bradaschia P. R. Brady A. Bramley A. Branch M. Branchesi J. E. Brau M. Breschi T. Briant J. H. Briggs A. Brillet M. Brinkmann P. Brockill A. F. Brooks J. Brooks D. D. Brown S. Brunett G. Bruno R. Bruntz J. Bryant T. Bulik H. J. Bulten A. Buonanno R. Buscicchio D. Buskulic C. Buy R. L. Byer L. Cadonati G. Cagnoli C. Cahillane J. Calderón Bustillo J. D. Callaghan T. A. Callis LIGO Laboratory California Institute of Technology Pasadena California 91125 USA Louisiana State University Baton Rouge Louisiana 70803 USA Dipartimento di Farmacia Università di Salerno I-84084 Fisciano Salerno Italy INFN Sezione di Napoli Complesso Universitario di Monte S. Angelo I-80126 Napoli Italy OzGrav School of Physics and Astronomy Monash University Clayton 3800 Victoria Australia LIGO Livingston Observatory Livingston Louisiana 70754 USA University of Wisconsin-Milwaukee Milwaukee Wisconsin 53201 USA OzGrav Australian National University Canberra Australian Capital Territory 0200 Australia Max Planck Institute for Gravitational Physics (Albert Einstein Institute) D-30167 Hannover Germany Leibniz Universität Hannover D-30167 Hannover Germany Inter-University Centre for Astronomy and Astrophysics Pune 411007 India University of Cambridge Cambridge CB2 1TN United Kingdom Theoretisch-Physikalisches Institut Friedrich-Schiller-Universität Jena D-07743 Jena Germany University of Birmingham Birmingham B15 2TT United Kingdom Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) Northwestern University Evanston Illinois 60208 USA Instituto Nacional de Pesquisas Espaciais 12227-010 São José dos Campos São Paulo Brazil Gravity Exploration Institute Cardiff University Cardiff CF24 3AA United Kingdom INFN Sezione di Pisa I-56127 Pisa Italy International Centre for Theoretical Sciences Tata Institute of Fundamental Research Bengaluru 560089 India Gravitational Wave Science Project National Astronomical Observatory of Japan (NAOJ) Mitaka City Tokyo 181-8588 Japan Advanced Technology Center National Astronomical Observatory of Japan (NAOJ) Mitaka City Tokyo 181-8588 Japan INFN Sezione di Torino I-10125 Torino Italy Università di Napoli “Federico II” Complesso Universitario di Monte S. Angelo I-80126 Napoli Italy Université de Lyon Université Claude Bernard Lyon 1 CNRS Institut Lumière Matière F-69622 Villeurbanne Franc

We present a search for dark photon dark matter that could couple to gravitational-wave interferometers using data from Advanced LIGO and Virgo’s third observing run. To perform this analysis, we use two methods, one based on cross-correlation of the strain channels in the two nearly aligned LIGO detectors, and one that looks for excess power in the strain channels of the LIGO and Virgo detectors. The excess power method optimizes the Fourier transform coherence time as a function of frequency, to account for the expected signal width due to Doppler modulations. We do not find any evidence of dark photon dark matter with a mass between mA∼10−14–10−11 eV/c2, which corresponds to frequencies between 10–2000 Hz, and therefore provide upper limits on the square of the minimum coupling of dark photons to baryons, i.e., U(1)B dark matter. For the cross-correlation method, the best median constraint on the squared coupling is ∼1.31×10−47 at mA∼4.2×10−13 eV/c2; for the other analysis, the best constraint is ∼2.4×10−47 at mA∼5.7×10−13 eV/c2. These limits improve upon those obtained in direct dark matter detection experiments by a factor of ∼100 for mA∼[2–4]×10−13 eV/c2, and are, in absolute terms, the most stringent constraint so far in a large mass range mA∼2×10−13–8×10−12 eV/c2.

关键词： Dark matter Gravitational wave detectors

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APPLICATION OF MFCAV RIEMANN SOLVER TO MAIRE＇S CELL-CENTERED LAGRANGIAN METHOD

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Journal of computational mathematics 2015年第2期33卷 128-145页

作者： Yan Liu Baolin Tian Weidong Shen Shuanghu Wang Song Jiang Dekang Mao Applied Physics and Computational Mathematics Beijing 100095 P. R. China Department of Mathematics Shanghai University Shanghai 200444 P. R China

In this paper, we apply arbitrary Riemann solvers, which may not satisfy the Maire＇s requirement, to the Maire＇s node-based Lagrangian scheme developed in [P. H. Maire et al., SIAM J. Sci. Comput, 29 （2007）, 1781-1824]. In particular, we apply the so-called Multi-Fluid Channel on Averaged Volume （MFCAV） Riemann solver and a Riemann solver that adaptively combines the MFCAV solver with other more dissipative Riemann solvers to the Maire＇s scheme. It is noted that neither of the two solvers satisfies the Maire＇s requirement. Numerical experiments are presented to demonstrate that the application of the two Riemann solvers is successful.

关键词： Maire＇s node-based Lagrangian scheme Riemann solvers Riemann invariants,weighted least squares procedure.

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Extremely scalable algorithm for 108-atom quantum material simulation on the full system of the K computer 7

Extremely scalable algorithm for 108-atom quantum material s...

引用

7th Workshop on Latest Advances in Scalable Algorithms for Large-Scale Systems, ScalA 2016

作者： Hoshi, Takeo Imachi, Hiroto Kumahata, Kiyoshi Terai, Masaaki Miyamoto, Kengo Minami, Kazuo Shoji, Fumiyoshi Department of Applied Mathematics and Physics Tottori University 4-101 Koyama-Minami Tottori Japan Operations and Computer Technologies Division RIKEN Advanced Institute for Computational Science 7-1-26 Minatojima-minami-machi Chuo-kuKobe Japan

ISBN: (纸本)9781509052226

An extremely scalable linear-algebraic algorithm was developed for quantum material simulation (electronic state calculation) with 108 atoms or 100-nm-scale materials. The mathematical foundation is generalized shifted linear equations ((zB - A)x = b), instead of conventional generalized eigenvalue equations. The method has a highly parallelizable mathematical structure. The benchmark shows an extreme strong scaling and a qualified time-to-solution on the full system of the K computer. The method was demonstrated in a real material research for ultra-flexible (organic) devices, key devices of next-generation Internet-of-Things (IoT) products. The present paper shows that an innovative scalable algorithm for a real research can appear by the co-design among application, algorithm and architecture. © 2016 IEEE.

关键词： Quantum theory

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Influence of multi-photon excitation on the atomic above-threshold ionization

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Chinese Physics B 2015年第4期24卷 138-142页

作者：田原野王春成李苏宇郭福明丁大军 Roeterdink Wim-Ga 陈基根曾思良刘学深杨玉军 Institute of Atomic and Molecular Physics Jilin University Jilin Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy Jilin University Department of Physics and Materials Engineering Taizhou University Data Center for High Energy Density Physics Institute of Applied Physics and Computational Mathematics Science and Technology Computational Physics Laboratory Institute of Applied Physics and Computational Mathematics

Using the time-dependent pseudo-spectral scheme, we solve the time-dependent Schrodinger equation of a hydrogen- like atom in a strong laser field in momentum space. The intensity-resolved photoelectron energy spectrum in abovethreshold ionization is obtained and further analyzed. We find that with the increase of the laser intensity, the abovethreshold ionization emission spectrum exhibits periodic resonance structure. By analyzing the population of atomic bound states, we find that it is the multi-photon excitation of bound state that leads to the occurrence of this phenomenon, which is in fairly good agreement with the experimental results.

关键词： time-dependent pseudo-spectral scheme above-threshold ionization resonance structure

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Topological crystalline antiferromagnetic state in tetragonal FeS

arXiv

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arXiv 2017年

作者： Hao, Ningning Zheng, Fawei Zhang, Ping Shen, Shun-Qing Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions High Magnetic Field Laboratory Chinese Academy of Sciences Hefei Anhui230031 China Collaborative Innovation Center of Advanced Microstructures Nanjing University Jiangsu Province210093 China Institute of Applied Physics and Computational Mathematics Beijing100088 China Beijing Computational Science Research Center Beijing100193 China Department of Physics University of Hong Kong Pokfulam Road Hong Kong Hong Kong

Integration between magnetism and topology is an exotic phenomenon in condensed-matter physics. Here, we propose an exotic phase named topological crystalline antiferromagnetic state, in which antiferromagnetism intrinsically integrates with nontrivial topology, and we suggest such a state can be realized in tetragonal FeS. A combination of first-principles calculations and symmetry analyses shows that the topological crystalline antiferromagnetic state arises from band reconstruction induced by pair checker-board antiferromagnetic order together with band-gap opening induced by intrinsic spin-orbit coupling in tetragonal FeS. The topological crystalline antiferromagnetic state is protected by the product of fractional translation symmetry, mirror symmetry, and time-reversal symmetry, and present some unique features. In contrast to strong topological insulators, the topological robustness is surface-dependent. These findings indicate that non-trivial topological states could emerge in pure antiferromagnetic materials, which sheds new light on potential applications of topological properties in fast-developing antiferromagnetic spintronics. Copyright © 2017, The Authors. All rights reserved.

关键词： Crystalline materials

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Intrinsic data depth for Hermitian positive definite matrices

arXiv

引用

arXiv 2017年

作者： Chau, Joris Ombao, Hernando von Sachs, Rainer Institute of Statistics Biostatistics and Actuarial Sciences Universite catholique de Louvain Voie du Roman Pays 20 Louvain-la-NeuveB-1348 Belgium Department of Statistics University of California at Irvine Bren Hall 2206 IrvineCA92697 United States Department of Applied Mathematics and Computational Science King Abdullah University of Science and Technology Thuwal23955-6900 Saudi Arabia

Nondegenerate covariance, correlation and spectral density matrices are necessarily symmetric or Hermitian and positive definite. The main contribution of this paper is the development of statistical data depths for collections of Hermitian positive definite matrices by exploiting the geometric structure of the space as a Riemannian manifold. The depth functions allow one to naturally characterize most central or outlying matrices, but also provide a practical framework for inference in the context of samples of positive definite matrices. First, the desired properties of an intrinsic data depth function acting on the space of Hermitian positive definite matrices are presented. Second, we propose two computationally fast pointwise and integrated data depth functions that satisfy each of these requirements and investigate several robustness and efficiency aspects. As an application, we construct depth-based confidence regions for the intrinsic mean of a sample of positive definite matrices, which is applied to the exploratory analysis of a collection of covariance matrices associated to a multicenter research trial.62G30, 62G15, 62G35, 62M15 Copyright © 2017, The Authors. All rights reserved.

关键词： Covariance matrix

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A simple and efficient co-operative approach for solving multi-modal problems

A simple and efficient co-operative approach for solving mul...

引用

International Conference on Electrical, Electronics, and Optimization Techniques (ICEEOT)

作者： Hira Zaheer Millie Pant Oleg Monakhov Emilia Monakhova Department of Applied Science and Engineering Indian Institute of Technology Roorkee Computer Systems Department Institute of Computational Mathematics and Mathematical Geophysics

In the present study a simple and efficient approach is proposed to enhance the performance of Differential Evolution algorithm, while maintaining its basic structure, for solving continuous global optimization problems. The proposed variant named cooperative DE or CDE is based on utilizing all the individuals of the population. The proposed variant is tested on a set of 15 unconstrained benchmark problems and results are compared with other four strategies of DE.

关键词： Sociology Statistics Video recording Optimization Benchmark testing STEM Computers

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