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Static Hopf solitons and knotted emergent fields in solid-state noncentrosymmetric magnetic nanostructures

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arXiv 2018年

作者： Tai, Jung-Shen B. Smalyukh, Ivan I. Department of Physics University of Colorado BoulderCO80309 United States Materials Science and Engineering Program Soft Materials Research Center Department of Electrical Computer and Energy Engineering University of Colorado BoulderCO80309 United States Renewable and Sustainable Energy Institute National Renewable Energy Laboratory University of Colorado BoulderCO80309 United States

Two-dimensional topological solitons, commonly called Skyrmions, are extensively studied in solid-state magnetic nanostructures and promise many spintronics applications. However, three-dimensional topological solitons dubbed hopfions have not been demonstrated as stable spatially localized structures in solid-state magnetic materials. Here we model the existence of such static solitons with different Hopf index values in noncentrosymmetric solid magnetic nanostructures with a perpendicular interfacial magnetic anisotropy. We show how this surface anisotropy, along with the Dzyaloshinskii-Moriya interactions and the geometry of nanostructures, stabilize hopfions. We demonstrate knots in emergent field lines and computer simulate Lorentz transmission electron microscopy images of such solitonic configurations to guide their experimental discovery in magnetic solids. Copyright © 2018, The Authors. All rights reserved.

关键词： Solitons

Binding a hopfion in chiral magnet nanodisk

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arXiv 2018年

作者： Liu, Yizhou Lake, Roger K. Zang, Jiadong Department of Electrical and Computer Engineering University of California RiversideCA92521 United States Department of Physics and Materials Science Program University of New Hampshire DurhamNH03824 United States Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sci-ences Beijing100190 China

Hopfions are three-dimensional (3D) topological textures characterized by the integer Hopf invariant QH. Here, we present the realization of a zero-field, stable hopfion spin texture in a magnetic system consisting of a chiral magnet nanodisk sandwiched by two films with perpendicular magnetic anisotropy. The preimages of the spin texture and numerical calculations of QH show that the hop-fion has QH = 1. Furthermore, another non-trivial state that includes a monopole{antimonopole pair (MAP) is also stabilized in this system. By applying an external magnetic field, hopfion and MAP states with the same polarization can be switched between each other. The topological transition between the hopfion and the MAP state involves a creation (annihilation) of the MAP and twist of the preimages. Our work paves the way to study non-trivial 3D topological spin textures and stimulates more investigations in the field of 3D spintronics. Copyright © 2018, The Authors. All rights reserved.

关键词： Textures

Nonreciprocal cavities and the time-bandwidth limit

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arXiv 2018年

作者： Mann, Sander A. Sounas, Dimitrios L. Alù, Andrea Department of Electrical and Computer Engineering University of Texas at Austin AustinTX United States Photonics Initiative Advanced Science Research Center City University of New York New York10031 United States Physics Program Graduate Center City University of New York New York10016 United States Department of Electrical Engineering City College of the City University of New York New York10031 United States

The time-bandwidth limit inherently relates the lifetime of a resonance and its spectral bandwidth, with direct implications on the maximum storage time of a pulse versus its frequency content. It has been recently argued that nonreciprocal cavities may overcome this constraint, by breaking the strict equality of their incoupling and outcoupling coefficients. Here, we generally study the implications of nonreciprocity on resonant cavities and derive general relations, stemming from microscopic reversibility, that govern their dynamics. We show that nonreciprocal cavities do not provide specific advantages in terms of the time-bandwidth limit, but they may have other attractive properties for nanophotonic systems. Copyright © 2018, The Authors. All rights reserved.

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Quantitative multimodal 3D characterization of cellular dynamics in wounded skin

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Quantitative multimodal 3D characterization of cellular dyna...

Bio-Optics: Design and Application, BODA 2017

作者： Li, Joanne Bower, Andrew J. Chaney, Eric J. Marjanovic, Marina Boppart, Stephen A. Beckman Institute for Advanced Science and Technology University of Illinois at Urbana-Champaign United States Department of Bioengineering University of Illinois at Urbana-Champaign United States Department of Electrical and Computer Engineering University of Illinois at Urbana-Champaign United States Department of Internal Medicine University of Illinois at Urbana-Champaign United States

Cell dynamics play a crucial role in wound healing. We report a multimodal analysis method to characterize cell dynamics and morphology. The outcome may provide insightful information about the skin microenvironment d... 详细信息

ISBN: (纸本)9781943580255

关键词： Dynamics

Quantifying Gerrymandering in North Carolina

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arXiv 2018年

作者： Herschlag, Gregory Kang, Han Sung Luo, Justin Graves, Christy Vaughn Bangia, Sachet Ravier, Robert Mattingly, Jonathan C. Department of Mathematics Duke University DurhamNC27708 United States Department of Biomedical Engineering Duke University DurhamNC27708 United States Department of Computer Science Duke University DurhamNC27708 United States Department of Electrical and Computer Engineering Duke University DurhamNC27708 United States Department of Economics Duke University DurhamNC27708 United States Program in Applied and Computational Mathematics Princeton University PrincetonNJ United States Department of Statistical Science Duke University DurhamNC27708 United States

Using an ensemble of redistricting plans, we evaluate whether a given political districting faithfully represents the geo-political landscape. Redistricting plans are sampled by a Monte Carlo algorithm from a probability distribution that adheres to realistic and non-partisan criteria. Using the sampled redistricting plans and historical voting data, we produce an ensemble of elections that reveal geo-political structure within the state. We showcase our methods on the two most recent districtings of NC for the U.S. House of Representatives, as well as a plan drawn by a bipartisan redistricting panel. We find the two state enacted plans are highly atypical outliers whereas the bipartisan plan accurately represents the ensemble both in partisan outcome and in the fine scale structure of district-level results. Copyright © 2018, The Authors. All rights reserved.

关键词： Probability distributions

High-speed two-photon fluorescence lifetime imaging microscopy of NADH for label-free metabolic imaging

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High-speed two-photon fluorescence lifetime imaging microsco...

Optical Molecular Probes, Imaging and Drug Delivery, OMP 2017

作者： Bower, Andrew J. Li, Joanne Chaney, Eric J. Marjanovic, Marina Boppart, Stephen A. Beckman Institute for Advanced Science and Technology University of Illinois at Urbana-Champaign United States Department of Electrical and Computer Engineering University of Illinois at Urbana-Champaign United States Department of Bioengineering University of Illinois at Urbana-Champaign United States Department of Internal Medicine University of Illinois at Urbana-Champaign United States

Two-photon fluorescence lifetime imaging microscopy (TP-FLIM) of reduced nicotinamide adenine dinucleotide is a sensitive metabolic imaging modality. Here, a video rate TP-FLIM system is demonstrated for metabolic ima... 详细信息

ISBN: (纸本)9781943580255

关键词： Photons

Polaritonic frequency-comb generation and breather propagation in a negative-index metamaterial with a cold four-level atomic medium

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arXiv 2019年

作者： Asgarnezhad-Zorgabad, Saeid Berini, Pierre Sanders, Barry C. Department of Physics Sharif University of Technology Tehran11365 11155 Iran Institute for Quantum Science and Technology University of Calgary CalgaryABT2N 1N4 Canada Department of Physics University of Ottawa 150 Louis-Pasteur OttawaONK1N 6N5 Canada Centre for Research in Photonics University of Ottawa 25 Templeton St. OttawaONK1N 6N5 Canada School of Electrical Engineering and Computer Science 700 King Edward St. OttawaONK1N 6N5 Canada Program in Quantum Information Science Canadian Institute for Advanced Research TorontoONM5G 1M1 Canada

We develop a concept for a waveguide that exploits spatial control of nonlinear surface-polaritonic waves. Our scheme includes an optical cavity with four-level N-type atoms in a lossless dielectric placed above a negative-index metamaterial layer. We propose exciting a polaritonic Akhmediev breather at a certain position of the interface between the atomic medium and the metamaterial by modifying laser-field intensities and detunings. Furthermore, we propose generating position-dependent polaritonic frequency combs by engineering widths of the electromagnetically induced transparency window commensurate with the surface-polaritonic modulation instability. Therefore, this waveguide acts as a high-speed polaritonic modulator and position-dependent frequency-comb generator, which can be applied to compact photonic chips. Copyright © 2019, The Authors. All rights reserved.

关键词： Metamaterials

Author Correction: Federated learning enables big data for rare cancer boundary detection

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Nature communications 2023年第1期14卷 436页

作者： Sarthak Pati Ujjwal Baid Brandon Edwards Micah Sheller Shih-Han Wang G Anthony Reina Patrick Foley Alexey Gruzdev Deepthi Karkada Christos Davatzikos Chiharu Sako Satyam Ghodasara Michel Bilello Suyash Mohan Philipp Vollmuth Gianluca Brugnara Chandrakanth J Preetha Felix Sahm Klaus Maier-Hein Maximilian Zenk Martin Bendszus Wolfgang Wick Evan Calabrese Jeffrey Rudie Javier Villanueva-Meyer Soonmee Cha Madhura Ingalhalikar Manali Jadhav Umang Pandey Jitender Saini John Garrett Matthew Larson Robert Jeraj Stuart Currie Russell Frood Kavi Fatania Raymond Y Huang Ken Chang Carmen Balaña Jaume Capellades Josep Puig Johannes Trenkler Josef Pichler Georg Necker Andreas Haunschmidt Stephan Meckel Gaurav Shukla Spencer Liem Gregory S Alexander Joseph Lombardo Joshua D Palmer Adam E Flanders Adam P Dicker Haris I Sair Craig K Jones Archana Venkataraman Meirui Jiang Tiffany Y So Cheng Chen Pheng Ann Heng Qi Dou Michal Kozubek Filip Lux Jan Michálek Petr Matula Miloš Keřkovský Tereza Kopřivová Marek Dostál Václav Vybíhal Michael A Vogelbaum J Ross Mitchell Joaquim Farinhas Joseph A Maldjian Chandan Ganesh Bangalore Yogananda Marco C Pinho Divya Reddy James Holcomb Benjamin C Wagner Benjamin M Ellingson Timothy F Cloughesy Catalina Raymond Talia Oughourlian Akifumi Hagiwara Chencai Wang Minh-Son To Sargam Bhardwaj Chee Chong Marc Agzarian Alexandre Xavier Falcão Samuel B Martins Bernardo C A Teixeira Flávia Sprenger David Menotti Diego R Lucio Pamela LaMontagne Daniel Marcus Benedikt Wiestler Florian Kofler Ivan Ezhov Marie Metz Rajan Jain Matthew Lee Yvonne W Lui Richard McKinley Johannes Slotboom Piotr Radojewski Raphael Meier Roland Wiest Derrick Murcia Eric Fu Rourke Haas John Thompson David Ryan Ormond Chaitra Badve Andrew E Sloan Vachan Vadmal Kristin Waite Rivka R Colen Linmin Pei Murat Ak Ashok Srinivasan J Rajiv Bapuraj Arvind Rao Nicholas Wang Ota Yoshiaki Toshio Moritani Sevcan Turk Joonsang Lee Snehal Prabhudesai Fanny Morón Jacob Mandel Konstantinos Kamnitsas Ben Glocker Luke V M Dixon Matthew Williams Peter Zamp Center for Biomedical Image Computing and Analytics (CBICA) University of Pennsylvania Philadelphia PA USA. Department of Radiology Perelman School of Medicine University of Pennsylvania Philadelphia PA USA. Department of Pathology and Laboratory Medicine Perelman School of Medicine University of Pennsylvania Philadelphia PA USA. Department of Informatics Technical University of Munich Munich Bavaria Germany. Intel Corporation Santa Clara CA USA. Department of Neuroradiology Heidelberg University Hospital Heidelberg Germany. Clinical Cooperation Unit Neuropathology German Cancer Consortium (DKTK) within the German Cancer Research Center (DKFZ) Heidelberg Germany. Department of Neuropathology Heidelberg University Hospital Heidelberg Germany. Division of Medical Image Computing German Cancer Research Center Heidelberg Germany. Pattern Analysis and Learning Group Department of Radiation Oncology Heidelberg University Hospital Heidelberg Germany. Neurology Clinic Heidelberg University Hospital Heidelberg Germany. Department of Radiology & Biomedical Imaging University of California San Francisco San Francisco CA USA. Symbiosis Center for Medical Image Analysis Symbiosis International University Pune Maharashtra India. Department of Neuroimaging and Interventional Radiology National Institute of Mental Health and Neurosciences Bangalore Karnataka India. Department of Radiology School of Medicine and Public Health University of Wisconsin Madison WI USA. Department of Medical Physics School of Medicine and Public Health University of Wisconsin Madison WI USA. Leeds Teaching Hospitals Trust Department of Radiology Leeds UK. Department of Radiology Brigham and Women's Hospital Harvard Medical School Boston MA USA. Athinoula A. Martinos Center for Biomedical Imaging Massachusetts General Hospital Charlestown MA USA. Catalan Institute of Oncology Badalona Spain. Consorci MAR Parc de Salut de Barcelona Catalonia Spain. Department of Radiology (IDI

Label-free 3D computational imaging of spermatozoon locomotion, head spin and flagellum beating over a large volume

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Light(science & Applications) 2017年第1期6卷 300-310页

作者： Mustafa Ugur Daloglu Wei Luo Faizan Shabbir Francis Lin Kevin Kim Inje Lee Jia-Qi Jiang Wen-Jun Cai Vishwajith Ramesh Meng-Yuan Yu Aydogan Ozcan Electrical and Computer Engineering Department University of CaliforniaLos AngelesCA 90095USA Bioengineering Department University of CaliforniaLos AngelesCA 90095USA California NanoSystems Institute(CNSI) University of CaliforniaLos AngelesCA 90095USA Chemistry and Biochemistry Department University of CaliforniaLos AngelesCA 90095USA Department of Physics and Astronomy University of CaliforniaLos AngelesCA 90095USA Department of Mathematics University of CaliforniaLos AngelesCA 90095USA Computer Science Department University of CaliforniaLos AngelesCA 90095USA Department of Surgery David Geffen School of MedicineUniversity of CaliforniaLos AngelesCA 90095USA

We report a high-throughput and label-free computational imaging technique that simultaneously measures in three-dimensional(3D)space the locomotion and angular spin of the freely moving heads of microswimmers and the beating patterns of their flagella over a sample volume more than two orders-of-magnitude larger compared to existing optical *** this platform,we quantified the 3D locomotion of 2133 bovine sperms and determined the spin axis and the angular velocity of the sperm head,providing the perspective of an observer seated at the moving and spinning sperm *** this constantly transforming perspective,flagellum-beating patterns are decoupled from both the 3D translation and spin of the head,which provides the opportunity to truly investigate the 3D spatio-temporal kinematics of the *** addition to providing unprecedented information on the 3D locomotion of microswimmers,this computational imaging technique could also be instrumental for micro-robotics and sensing research,enabling the high-throughput quantification of the impact of various stimuli and chemicals on the 3D swimming patterns of sperms,motile bacteria and other micro-organisms,generating new insights into taxis behaviors and the underlying biophysics.

关键词： flagellar motion holography on-chip microscopy sperm head spin sperm tracking