41,475 results match your criteria Astronomy Reports[Journal]

Multifunctional antiferromagnetic materials with giant piezomagnetism and noncollinear spin current.

Nat Commun 2021 May 14;12(1):2846. Epub 2021 May 14.

Department of Physics, The Hong Kong University of Science and Technology, Hong Kong, China.

We propose a new type of spin-valley locking (SVL), named C-paired SVL, in antiferromagnetic systems, which directly connects the spin/valley space with the real space, and hence enables both static and dynamical controls of spin and valley to realize a multifunctional antiferromagnetic material. The new emergent quantum degree of freedom in the C-paired SVL is comprised of spin-polarized valleys related by a crystal symmetry instead of the time-reversal symmetry. Thus, both spin and valley can be accessed by simply breaking the corresponding crystal symmetry. Read More

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Modulating the voltage sensor of a cardiac potassium channel shows antiarrhythmic effects.

Proc Natl Acad Sci U S A 2021 May;118(20)

Department of Biomedical Engineering, Washington University, St. Louis, MO 63130;

Cardiac arrhythmias are the most common cause of sudden cardiac death worldwide. Lengthening the ventricular action potential duration (APD), either congenitally or via pathologic or pharmacologic means, predisposes to a life-threatening ventricular arrhythmia, Torsade de Pointes. I (KCNQ1+KCNE1), a slowly activating K current, plays a role in action potential repolarization. Read More

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Electronic, magnetic, vibrational, and X-ray spectroscopy of inverse full-Heusler FeIrSi alloy.

Phys Chem Chem Phys 2021 May 14. Epub 2021 May 14.

Physical Sciences Research Center (PSRC), Department of Physics, Pachhunga University College, Mizoram University, Aizawl-796001, India.

We report the electronic, magnetic, structural, vibrational, and X-ray absorption spectroscopy of the inverse full-Heusler Fe2IrSi alloy. We employed state-of-the-art first-principles computational techniques. Our ab initio calculations revealed a ferromagnetic half-metallicity with a magnetic moment of ∼5. Read More

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Correlated Magnetic Weyl Semimetal State in Strained Pr Ir O.

Adv Mater 2021 May 14:e2008528. Epub 2021 May 14.

Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul, 08826, Republic of Korea.

Correlated topological phases (CTPs) with interplay between topology and electronic correlations have attracted tremendous interest in condensed matter physics. Therein, correlated Weyl semimetals (WSMs) are rare in nature and, thus, have so far been less investigated experimentally. In particular, the experimental realization of the interacting WSM state with logarithmic Fermi velocity renormalization has not been achieved yet. Read More

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Thermodynamics of a Two-Step Electroweak Phase Transition.

Phys Rev Lett 2021 Apr;126(17):171802

Department of Physics and Helsinki Institute of Physics, P.O. Box 64, FI-00014 University of Helsinki, Finland.

New field content beyond that of the standard model of particle physics can alter the thermal history of electroweak symmetry breaking in the early Universe. In particular, the symmetry breaking may have occurred through a sequence of successive phase transitions. We study the thermodynamics of such a scenario in a real triplet extension of the standard model, using nonperturbative lattice simulations. Read More

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Entanglement and Purification Transitions in Non-Hermitian Quantum Mechanics.

Phys Rev Lett 2021 Apr;126(17):170503

Joint Center for Quantum Information and Computer Science, NIST/University of Maryland, College Park, Maryland 20742 USA.

A quantum system subject to continuous measurement and postselection evolves according to a non-Hermitian Hamiltonian. We show that, as one increases the strength of postselection, this non-Hermitian Hamiltonian can undergo a spectral phase transition. On one side of this phase transition (for weak postselection), an initially mixed density matrix remains mixed at all times, and an initially unentangled state develops volume-law entanglement; on the other side, an arbitrary initial state approaches a unique pure state with low entanglement. Read More

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Measurement of the 2νββ Decay Half-Life of ^{130}Te with CUORE.

Phys Rev Lett 2021 Apr;126(17):171801

INFN-Sezione di Roma, Roma I-00185, Italy.

We measured two-neutrino double beta decay of ^{130}Te using an exposure of 300.7 kg yr accumulated with the CUORE detector. Using a Bayesian analysis to fit simulated spectra to experimental data, it was possible to disentangle all the major background sources and precisely measure the two-neutrino contribution. Read More

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Time-Domain Anyon Interferometry in Kitaev Honeycomb Spin Liquids and Beyond.

Phys Rev Lett 2021 Apr;126(17):177204

Department of Physics and Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125, USA.

Motivated by recent experiments on the Kitaev honeycomb magnet α-RuCl_{3}, we introduce time-domain probes of the edge and quasiparticle content of non-Abelian spin liquids. Our scheme exploits ancillary quantum spins that communicate via time-dependent tunneling of energy into and out of the spin liquid's chiral Majorana edge state. We show that the ancillary-spin dynamics reveals the edge-state velocity and, in suitable geometries, detects individual non-Abelian anyons and emergent fermions via a time-domain counterpart of quantum-Hall anyon interferometry. Read More

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Implications of PREX-2 on the Equation of State of Neutron-Rich Matter.

Phys Rev Lett 2021 Apr;126(17):172503

Department of Physics, Florida State University, Tallahassee, Florida 32306, USA.

Laboratory experiments sensitive to the equation of state of neutron rich matter in the vicinity of nuclear saturation density provide the first rung in a "density ladder" that connects terrestrial experiments to astronomical observations. In this context, the neutron skin thickness of ^{208}Pb (R_{skin}^{208}) provides a stringent laboratory constraint on the density dependence of the symmetry energy. In turn, an improved value of R_{skin}^{208} has been reported recently by the PREX collaboration. Read More

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Cavity-QED Quantum Simulator of Dynamical Phases of a Bardeen-Cooper-Schrieffer Superconductor.

Phys Rev Lett 2021 Apr;126(17):173601

JILA, NIST, Department of Physics, University of Colorado, Boulder, Colorado 80309, USA.

We propose to simulate dynamical phases of a BCS superconductor using an ensemble of cold atoms trapped in an optical cavity. Effective Cooper pairs are encoded via the internal states of the atoms, and attractive interactions are realized via the exchange of virtual photons between atoms coupled to a common cavity mode. Control of the interaction strength combined with a tunable dispersion relation of the effective Cooper pairs allows exploration of the full dynamical phase diagram of the BCS model as a function of system parameters and the prepared initial state. Read More

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Interrelation of Elasticity and Thermal Bath in Nanotube Cantilevers.

Phys Rev Lett 2021 Apr;126(17):175502

ICFO-Institut De Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain.

We report the first study on the thermal behavior of the stiffness of individual carbon nanotubes, which is achieved by measuring the resonance frequency of their fundamental mechanical bending modes. We observe a reduction of the Young's modulus over a large temperature range with a slope -(173±65)  ppm/K in its relative shift. These findings are reproduced by two different theoretical models based on the thermal dynamics of the lattice. Read More

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Floquet Engineering Correlated Materials with Unpolarized Light.

V L Quito R Flint

Phys Rev Lett 2021 Apr;126(17):177201

Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.

Floquet engineering is a powerful tool that drives materials with periodic light. Traditionally, the light is monochromatic, with amplitude, frequency, and polarization varied. We introduce Floquet engineering via unpolarized light built from quasimonochromatic light and show how it can modify strongly correlated systems, while preserving the original symmetries. Read More

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3D Imaging from Multipath Temporal Echoes.

Phys Rev Lett 2021 Apr;126(17):174301

School of Physics & Astronomy, University of Glasgow, Glasgow G12 8QQ, United Kingdom.

Echo location is a broad approach to imaging and sensing that includes both manmade RADAR, LIDAR, SONAR, and also animal navigation. However, full 3D information based on echo location requires some form of scanning of the scene in order to provide the spatial location of the echo origin-points. Without this spatial information, imaging objects in three-dimensional (3D) is a very challenging task as the inverse retrieval problem is strongly ill-posed. Read More

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Prospects for Measuring the Hubble Constant with Neutron-Star-Black-Hole Mergers.

Phys Rev Lett 2021 Apr;126(17):171102

Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ, United Kingdom.

Gravitational wave (GW) and electromagnetic (EM) observations of neutron-star-black-hole (NSBH) mergers can provide precise local measurements of the Hubble constant (H_{0}), ideal for resolving the current H_{0} tension. We perform end-to-end analyses of realistic populations of simulated NSBHs, incorporating both GW and EM selection for the first time. We show that NSBHs could achieve unbiased 1. Read More

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Sierpiński Structure and Electronic Topology in Bi Thin Films on InSb(111)B Surfaces.

Phys Rev Lett 2021 Apr;126(17):176102

Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.

Deposition of Bi on InSb(111)B reveals a striking Sierpiński-triangle (ST)-like structure in Bi thin films. Such a fractal geometric topology is further shown to turn off the intrinsic electronic topology in a thin film. Relaxation of a huge misfit strain of about 30% to 40% between Bi adlayer and substrate is revealed to drive the ST-like island formation. Read More

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Structural Landscapes in Geometrically Frustrated Smectics.

Phys Rev Lett 2021 Apr;126(17):177801

Mathematical Institute, University of Oxford, Oxford OX2 6GG, United Kingdom.

A phenomenological free energy model is proposed to describe the behavior of smectic liquid crystals, an intermediate phase that exhibits orientational order and layering at the molecular scale. Advantageous properties render the functional amenable to numerical simulation. The model is applied to a number of scenarios involving geometric frustration, leading to emergent structures such as focal conic domains and oily streaks and enabling detailed elucidation of the very rich energy landscapes that arise in these problems. Read More

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Universality of Time-Temperature Scaling Observed by Neutron Spectroscopy on Bottlebrush Polymers.

Nano Lett 2021 May 14. Epub 2021 May 14.

Department of Physics & Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, United States.

The understanding of materials requires access to the dynamics over many orders of magnitude in time; however, single analytical techniques are restricted in their respective time ranges. Assuming a functional relationship between time and temperature is one viable tool to overcome these limits. Despite its frequent usage, a breakdown of this assertion at the glass-transition temperature is common. Read More

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Biomembrane Structure and Material Properties Studied With Neutron Scattering.

Front Chem 2021 27;9:642851. Epub 2021 Apr 27.

Oak Ridge National Laboratory, Shull-Wollan Center, Oak Ridge, TN, United States.

Cell membranes and their associated structures are dynamical supramolecular structures where different physiological processes take place. Detailed knowledge of their static and dynamic structures is therefore needed, to better understand membrane biology. The structure-function relationship is a basic tenet in biology and has been pursued using a range of different experimental approaches. Read More

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Cues to gender and racial identity reduce creativity in diverse social networks.

Sci Rep 2021 May 13;11(1):10261. Epub 2021 May 13.

Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY, USA.

The characteristics of social partners have long been hypothesized as influential in guiding group interactions. Understanding how demographic cues impact networks of creative collaborators is critical for elevating creative performances therein. We conducted a randomized experiment to investigate how the knowledge of peers' gender and racial identities distorts people's connection patterns and the resulting creative outcomes in a dynamic social network. Read More

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A continuous metal-insulator transition driven by spin correlations.

Nat Commun 2021 May 13;12(1):2779. Epub 2021 May 13.

Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA, 91125, USA.

While Mott insulators induced by Coulomb interactions are a well-recognized class of metal-insulator transitions, insulators purely driven by spin correlations are much less common, as the reduced energy scale often invites competition from other degrees of freedom. Here, we demonstrate a clean example of a spin-correlation-driven metal-insulator transition in the all-in-all-out pyrochlore antiferromagnet CdOsO, where the lattice symmetry is preserved by the antiferromagnetism. After the antisymmetric linear magnetoresistance from conductive, ferromagnetic domain walls is removed experimentally, the bulk Hall coefficient reveals four Fermi surfaces of both electron and hole types, sequentially departing the Fermi level with decreasing temperature below the Néel temperature, T = 227 K. Read More

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Unusual layer-by-layer growth of epitaxial oxide islands during Cu oxidation.

Nat Commun 2021 May 13;12(1):2781. Epub 2021 May 13.

Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA, USA.

Elucidating metal oxide growth mechanisms is essential for precisely designing and fabricating nanostructured oxides with broad applications in energy and electronics. However, current epitaxial oxide growth methods are based on macroscopic empirical knowledge, lacking fundamental guidance at the nanoscale. Using correlated in situ environmental transmission electron microscopy, statistically-validated quantitative analysis, and density functional theory calculations, we show epitaxial CuO nano-island growth on Cu is layer-by-layer along CuO(110) planes, regardless of substrate orientation, contradicting classical models that predict multi-layer growth parallel to substrate surfaces. Read More

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Crystallization of nanoparticles induced by precipitation of trace polymeric additives.

Nat Commun 2021 May 13;12(1):2767. Epub 2021 May 13.

Department of Materials Science and Engineering, University of California, Berkeley, CA, USA.

Orthogonal to guided growth of nanoparticle (NP) crystals using DNA or supramolecules, a trace amount of polymeric impurities (<0.1 wt.%) leads to reproducible, rapid growth of 3D NP crystals in solution and on patterned substrates with high yield. Read More

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The chain of chirality transfer in tellurium nanocrystals.

Science 2021 May;372(6543):729-733

Materials Sciences Division, Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.

Despite persistent and extensive observations of crystals with chiral shapes, the mechanisms underlying their formation are not well understood. Although past studies suggest that chiral shapes can form because of crystallization in the presence of chiral additives, or because of an intrinsic tendency that stems from the crystal structure, there are many cases in which these explanations are not suitable or have not been tested. Here, an investigation of model tellurium nanocrystals provides insights into the chain of chirality transfer between crystal structure and shape. Read More

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Adaptive optics control using model-based reinforcement learning.

Opt Express 2021 May;29(10):15327-15344

Reinforcement learning (RL) presents a new approach for controlling adaptive optics (AO) systems for Astronomy. It promises to effectively cope with some aspects often hampering AO performance such as temporal delay or calibration errors. We formulate the AO control loop as a model-based RL problem (MBRL) and apply it in numerical simulations to a simple Shack-Hartmann Sensor (SHS) based AO system with 24 resolution elements across the aperture. Read More

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Faradic capacitive deionization (FCDI) for desalination and ion removal from wastewater.

Chemosphere 2021 Jul 17;275:130001. Epub 2021 Feb 17.

Department of Sustainable and Renewable Energy Engineering, University of Sharjah, PO Box 27272, Sharjah, United Arab Emirates; Mechanical Engineering and Design, Aston University, School of Engineering and Applied Science, Aston Triangle, Birmingham, B4 7ET, UK. Electronic address:

Capacitive deionization (CDI) is one of the emerging desalination technologies that attracted much attention in the last years as a low-cost, energy-efficient, and environmentally-friendly alternative to other desalination technologies, such as multi-stage flash desalination (MSF) and multiple effect distillation (MED). The implementation of faradaic electrode materials is a promising method for enhancing CDI systems' performance by achieving higher salt removal characteristics, lower energy consumption, and better ion selectivity. Therefore, a novel CDI technology named Faradaic CDI (FCDI) that implements faradaic electrode materials arose as a high-performance CDI cell design. Read More

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25-hydroxycholesterol interacts differently with lipids of the inner and outer membrane leaflet - The Langmuir monolayer study complemented with theoretical calculations.

J Steroid Biochem Mol Biol 2021 May 10:105909. Epub 2021 May 10.

Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland.

25-hydroxycholesterol (25-OH), a molecule with unusual behavior at the air/water interface, being anchored to the water surface alternatively with a hydroxyl group at C(3) or C(25), has been investigated in mixtures with main membrane phospholipids (phosphatidylcholines - PCs, and phosphatidylethanolamines - PEs), characteristic of the outer and inner membrane leaflet, respectively. To achieve this goal, the classical Langmuir monolayer approach based on thermodynamic analysis of interactions was conducted in addition to microscopic imaging of films (in situ with BAM and after transfer onto mica with AFM), surface-sensitive spectroscopy (PM-IRRAS), as well as theoretical calculations. Our results show that the strength of interactions is primarily determined by the kind of polar group (strong, attractive interactions leading to surface complexes formation were found to occur with PCs while weak or repulsive ones with PEs). Read More

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A novel Vancomycin-Functionalized-Magnetic Graphene Composite for Use as a Near-Infrared-Induced Synergistic Chemo-Photothermal Antibacterial.

Macromol Biosci 2021 May 13:e2100082. Epub 2021 May 13.

Laboratory of Nanoscale Biosensing and Bioimaging (NBAB), School of Ophthalmology and Optometry, School of Biomedical Engineering, State Key Laboratory of Ophthalmology, Optometry, and Vision Science, Wenzhou Medical University, Wenzhou, Zhejiang, 325027, China.

Antibiotic-resistant bacterial strains are a major cause of disease. They continue to remain a challenge in the clinic particularly in the vision system. For example, infectious endophthalmitis is a major blind-causing disease caused by bacteria. Read More

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