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Fate of multipolar physics in 5d2 double perovskites

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Physical Review B 2023年第4期108卷 045149-045149页

作者： Ahmed Rayyan Xiaoyu Liu Hae-Young Kee Department of Physics University of Toronto Toronto Ontario Canada M5S 1A7 Department of Materials Science and Engineering University of Washington Seattle Washington 98195 USA CIFAR Program in Quantum Materials Canadian Institute for Advanced Research Toronto Ontario Canada M5G 1M1

In a cubic environment, the ground state of spin-orbit coupled 5d2 ions is a non-Kramers Eg doublet, which hosts quadrupole and octupole moments. A series of 5d2 osmium double perovskites Ba2MOsO6 (M=Mg, Ca, Zn, Cd) have recently been proposed to exhibit multipolar orders. We investigate the structural properties of these materials using ab initio calculations and find that the cubic structure is unstable for the Cd compound while the Mg, Ca, and Zn materials retain Fm3¯m symmetry. We show that Ba2CdOsO6 favors a rhombohedral R3¯ structure characterized by a−a−a− octahedral tiltings as indicated by unstable T1g phonon modes. Trigonal distortions split the excited T2g triplet into an Eg′ doublet and an Ag singlet, which may cross energy levels with the Eg doublet and suppress the multipolar physics. We find a window where Eg remains the lowest energy state under trigonal distortion, enabling the emergence of multipole phases in noncubic crystal environments.

关键词： Spin-orbit coupling Mott insulators Perovskites Crystal-field theory Density functional theory

Loss tangent fluctuations due to two-level systems in superconducting microwave resonators

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arXiv 2024年

作者： Vallières, André Russell, Megan E. You, Xinyuan Garcia-Wetten, David A. Goronzy, Dominic P. Walker, Mitchell J. Bedzyk, Michael J. Hersam, Mark C. Romanenko, Alexander Lu, Yao Grassellino, Anna Koch, Jens McRae, Corey Rae H. Graduate Program in Applied Physics Northwestern University EvanstonIL60208 United States Fermi National Accelerator Laboratory BataviaIL60510 United States Department of Physics and Astronomy Northwestern University EvanstonIL60208 United States Department of Materials Science and Engineering Northwestern University EvanstonIL60208 United States Department of Chemistry Northwestern University EvanstonIL60208 United States Department of Electrical and Computer Engineering Northwestern University EvanstonIL60208 United States Center for Applied Physics and Superconducting Technologies Northwestern University EvanstonIL60208 United States Electrical Computing and Energy Engineering Department University of Colorado BoulderCO80309 United States Department of Physics University of Colorado BoulderCO80309 United States National Institute of Standards and Technology BoulderCO80305 United States

Superconducting microwave resonators are critical to quantum computing and sensing technologies. Additionally, they are common proxies for superconducting qubits when determining the effects of performance-limiting loss mechanisms such as from two-level systems (TLS). The extraction of these loss mechanisms is often performed by measuring the internal quality factor Qi as a function of power or temperature. In this work, we investigate large temporal fluctuations of Qi at low powers over periods of 12 to 16 hours (relative standard deviation σQi/Qi = 13%). These fluctuations are ubiquitous across multiple resonators, chips and cooldowns. We are able to attribute these fluctuations to variations in the TLS loss tangent due to two main indicators. First, measured fluctuations decrease as power and temperature increase. Second, for interleaved measurements, we observe correlations between low- and medium-power Qi fluctuations and an absence of correlations with high-power fluctuations. Agreement with the TLS loss tangent mean is obtained by performing measurements over a time span of a few hours. We hypothesize that, in addition to decoherence due to coupling to individual near-resonant TLS, superconducting qubits are affected by these observed TLS loss tangent fluctuations. © 2024, CC BY.

关键词： Qubits

TAROGE-M: Antarctic High-Mountain Radio Antenna Array for Detecting Ultra-High Energy ANITA Anomalous Events 38

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TAROGE-M: Antarctic High-Mountain Radio Antenna Array for De...

38th International Cosmic Ray Conference, ICRC 2023

作者： Wang, Shih-Hao Chen, Pisin Chen, Yaocheng Chen, Ying-Chih Choi, Taejin Ham, Young-Bae Hsu, Shih-Ying Huang, Jian-Jung Huang, MingHuey A. Jee, Geonhwa Jung, Jongil Kim, Jieun Kuo, Chung-Yun Kwon, Hyuck-Jin Lee, Changsup Leung, Chung-Hei Liu, Tsung-Che Nam, Jiwoo Shiao, Yu-Shao J. Shin, Bok-Kyun Su, Shih-Chieh Wang, Min-Zu Wang, Shih-Hao Wang, Yu-Hsin Anker, Astrid Barwick, Steven W. Besson, Dave Z. Bouma, Sjoerd Cataldo, Maddalena Gaswint, Geoffrey Glaser, Christian Hallmann, Steffen Hanson, Jordan C. Henrichs, Jakob Kleinfelder, Stuart A. Lahmann, Robert Meyers, Zachary S. Nelles, Anna Novikov, Alexander Paul, Manuel P. Pyras, Lilly Persichilli, Christopher Plaisier, Ilse Rice-Smith, Ryan Seikh, Mohammad F. H. Tatar, Joulien Welling, Christoph Zhao, Leshan Department of Physics National Taiwan University Taipei10617 Taiwan Leung Center for Cosmology and Particle Astrophysics National Taiwan University Taipei10617 Taiwan Kavli Institute for Particle Astrophysics and Cosmology SLAC National Accelerator Laboratory Stanford University StanfordCA94305 United States Division of Atmospheric Sciences Korea Polar Research Institute Incheon Korea Republic of Department of Polar Science Korea University of Science and Technology Daejeon Korea Republic of Department of Energy Engineering National United University Miaoli Taiwan Department of Astronomy Space Science and Geology Chungnam National University Daejeon34134 Korea Republic of Department of Physics and Astronomy University of Delaware NewarkDE19716 United States Department of Electrophysics National Yang Ming Chiao Tung University Hsinchu300 Taiwan Department of applied physics National Pingtung university Pingtung900 Taiwan Chung Cheng Institute of Technology National Defense University Taoyuan335 Taiwan Undergraduate Degree Program of Systems Engineering and Technology National Yang Ming Chiao Tung University Hsinchu300 Taiwan National Nano Device Laboratories Hsinchu300 Taiwan Ulsan National Institute of Science and Technology Ulsan44919 Korea Republic of Institute of Astronomy and Astrophysics Academia Sinica Astronomy-Mathematics Building No. 1 Sec. 4 Roosevelt Rd. Taipei10617 Taiwan Department of Physics and Astronomy University of California IrvineCA92697 United States Department of Physics and Astronomy University of Kansas LawrenceKS66045 United States DESY Zeuthen15738 Germany ECAP Friedrich-Alexander-Universität Erlangen-Nürnberg Erlangen91058 Germany Uppsala University Department of Physics and Astronomy UppsalaSE-752 37 Sweden Whittier College Department of Physics WhittierCA90602 United States Department of Electrical Engineering and Computer Science University of California IrvineCA92697 United States Resea

TAROGE-M is a radio antenna array atop ∼ 2.7 km-high Mt. Melbourne in Antarctica for detecting ultra-high energy (UHE, E > 1017 eV) air showers in near-horizontal directions. Besides the detection of cosmic rays and Earth-skimming tau neutrinos, its primary goal is to reproduce the discovery and verify the origin of so-called ANITA anomalous events, having feature of upward-going UHE air showers but cannot be explained by tau neutrinos. The detection concept takes advantages of a high altitude for a broad view toward the horizon;strong and near-vertical geomagnetic field for enhancing the radio signal;and quiet radio environment in Antarctica. Its relatively simple design and high duty cycle make it easily to be extended and thus to achieve an exposure competitive with ANITA experiments within a few years. The first TAROGE-M station operating at 180-450 MHz frequencies deployed in 2020 detected seven UHE cosmic ray events within 25.3-day livetime. The events have a mean energy of ∼ 1 EeV and an estimated flux consistent with other experiments, and validate the station as an UHE particle detector. In 2022-2023 season, the system was upgraded for a robust long-term operation, with a more detailed calibration with a drone-borne pulser. We also discuss the planned upgrade, including the implementation of interferometric trigger, which is expected to increase the cosmic ray and tau neutrino acceptances by a factor of 10 at 0.1 EeV, corresponding to a lower energy threshold by a factor of 3. © Copyright owned by the author(s) under the terms of the Creative Commons.

关键词： Cosmic rays

Assessment of Electrocoagulation Control System Strategy in Textile Wastewater Treatment Plant

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Assessment of Electrocoagulation Control System Strategy in ...

2020 International Electronics Symposium, IES 2020

作者： Efendy, Bobby Ekawati, Estiyanti Nazuwatussyadiyah Budi, Eko Mursito Institut Teknologi Bandung Engineering Physics Program Faculty of Industrial Technology Bandung Indonesia Center for Instrumentation Technology and Automation Institut Teknologi Bandung Engineering Physics Research Group Faculty of Industrial Technology Bandung Indonesia

ISBN: (纸本)9781728195308

Electrocoagulation is a method of wastewater treatment that applies an electrical current into the liquid to coagulate the suspended particles. This study assessed two control strategies for electrocoagulation systems in wastewater treatment in terms of dynamic performances and energy consumptions. The first control strategy used the electrical current as a manipulated variable, and the second used the waste liquid flowrate instead. For either strategy, the controlled output was the turbidity of the product liquid. The assessment was conducted in an experimental setting, in a laboratory-scale, continuous pilot plant. The experiment began with the identification of the dynamic characteristics of the electrocoagulation process due to the combined changes in the electrical current between 1.8-5.2 Ampere and the changes in waste flowrate between 10.37-14.67 ml/s. First-Order-Process-with-Time-Delay equations approximated these processes. The statistical Analysis of Variance was used to select the best process condition to compare two control strategies. The associated Proportional Integral controllers were designed and applied for either strategy. The experiment showed that manipulating electrical current yield 7.48% longer settling time, but with significantly lower energy consumption throughout the electrocoagulation process. The result highlighted the benefit of using electrical current as of the manipulated variable in the electrocoagulation process in the pilot plant. © 2020 IEEE.

关键词： Wastewater treatment

Three-dimensional morphology of an ultrafine Al-Si eutectic produced via laser rapid solidification

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arXiv 2023年

作者： Zhou, Xinyi Chao, Paul Sloan, Luke Lien, Huai-Hsun Hunter, Allen H. Misra, Amit Shahani, Ashwin J. Engineering Physics Program University of Michigan Ann ArborMI48109 United States Department of Materials Science and Engineering University of Michigan Ann ArborMI48109 United States Michigan Center for Materials Characterization University of Michigan Ann ArborMI48109 United States Department of Chemical Engineering University of Michigan Ann ArborMI48109 United States

Al-Si alloys processed by laser rapid solidification yield eutectic microstructures with ultrafine and interconnected fibers. Such fibrous structures have long been thought to bear resemblance to those formed in impurity-doped alloys upon conventional casting. Here, we show that any similarity is purely superficial. By harnessing high-throughput characterization and computer vision techniques, we perform a three-dimensional analysis of the branching behavior of the ultrafine eutectic and compare it against an impurity-modified eutectic as well as a random fractal (as a benchmark). Differences in the branching statistics point to different microstructural origins of the impurity- and quench-modified eutectic. Our quantitative approach is not limited to the data presented here but can be used to extract abstract information from other volumetric datasets, without customization. © 2023, CC BY.

关键词： Eutectics

The analysis of adsorption capacity in heavy metal ions by using activated carbon from sago waste

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AIP Conference Proceedings 2024年第1期3074卷

作者： Octolia Togibasa Khaeriah Dahlan Yane Oktovina Ansanay Martina Bunga Daniel Napitupulu Tatang Sutarman Piter Wilson Wafumilena Beatrix Yuliana Nukuboy Physics Study Program Department of Physics Universitas Cenderawasih Jl. Kamp Wolker Jayapura 99358 Indonesia Geophysical Engineering Study Program Department of Physics Universitas Cenderawasih Jl. Kamp Wolker Jayapura 99358 Indonesia

Activated carbon is an interesting and third-highest-studied material due to its wide range of applications and environmental benefits. Activated carbon is also a promising material processed from sago waste in order to improve its economic value. The Sago waste utilized was obtained from the local community in Maribu Village, Jayapura, Papua, Indonesia and the fabrication process includes dehydration, carbonization, and chemical activation of KOH with 20% concentration. In this study, activated carbon was characterized with a scanning electron microscopy, X-ray diffractometer, as well as Fourier-transformed infrared spectroscopy to analyze the crystalline structure, morphology, and functional groups. The end product of the activated carbon was utilized to adsorb Hg(II), Cd(II), as well as Pb(II) heavy metal ions. The adsorption capacity was then examined with Atomic Absorption Spectroscopy using an analytical method. This study’s result showed that the activated carbon has mesoporous characteristics with fine structure and morphology. Therefore, the material was suitable for use as heavy metal adsorbent, with high absorption efficiency of over 80%.

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High pressure synthesis and characterization of the pyrochlore Dy2Pt2O7:A new spin ice material

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Chinese physics B 2020年第4期29卷 116-120页

作者： Qi Cui Yun-Qi Cai Xiang Li Zhi-Ling Dun Pei-Jie Sun Jian-Shi Zhou Hai-Dong Zhou Jin-Guang Cheng Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China Materials Science and Engineering Program Mechanical EngineeringUniversity of Texas at AustinAustinTexas 78712USA Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement of Ministry of Education School of PhysicsBeijing Institute of TechnologyBeijing 100081China Department of Physics and Astronomy University of TennesseeKnoxvilleTN 37996USA School of Physics Georgia Institute of TechnologyAtlantaGA 30332USA Songshan Lake Materials Laboratory Dongguan 523808China

The cubic pyrochlore Dy2Pt2O7 was synthesized under 4 GPa and 1000℃ and its magnetic and thermodynamic properties were characterized by DC and AC magnetic susceptibility and specific heat down to 0.1 *** found that Dy2Pt2O7 does not form long-range magnetic order,but displays characteristics of canonical spin ice such as Dy2Pt2O7,including(1)a large effective moment 9.64μB close to the theoretical value and a small positive Curie-Weiss temperatureθCW=+0.77 K signaling a dominant ferromagnetic interaction among the Ising spins;(2)a saturation moment ~4.5μB being half of the total moment due to the local<111>Ising anisotropy;(3)thermally activated spin relaxation behaviors in the low(~1 K)and high(~20 K)temperature regions with different energy barriers and characteristic relaxation time;and most importantly,(4)the presence of a residual entropy close to Pauling’s estimation for water ice.

关键词： Dy2Pt2O7 pyrochlore oxide spin ice high-pressure synthesis

Unavoidable emergent biaxiality in chiral molecular-colloidal hybrid liquid crystals

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arXiv 2023年

作者： Wu, Jin-Sheng Lázaro, Marina Torres Ghosh, Souvik Mundoor, Haridas Wensink, Henricus H. Smalyukh, Ivan I. Department of Physics and Chemical Physics Program University of Colorado BoulderCO United States Laboratoire de Physique des Solides UMR 8502 Université Paris-Saclay CNRS Orsay91405 France International Institute for Sustainability with Knotted Chiral Meta Matter Hiroshima University Higashihiroshima Japan Department of Electrical Computer and Energy Engineering Materials Science and Engineering Program and Soft Materials Research Center University of Colorado BoulderCO United States Renewable and Sustainable Energy Institute National Renewable Energy Laboratory University of Colorado BoulderCO80309 United States

Chiral nematic or cholesteric liquid crystals (LCs) are chiral mesophases with long-ranged orientational order featuring a quasi-layered periodicity imparted by a helical director configuration but lacking positional order. Doping molecular cholesteric LCs with thin colloidal rods with a large length-to-width ratio or disks with a large diameter-to-thickness ratio adds another level of complexity to the system because of the interplay between weak surface anchoring boundary conditions and bulk-based elastic distortions around the particle-LC interface. By using colloidal disks and rods with different geometric shapes and boundary conditions, we demonstrate that these anisotropic colloidal inclusions exhibit biaxial orientational probability distributions, where they have tendencies to orient with the long rod axes and disk normals perpendicular to the helix axis, thus imparting strong local biaxiality on the hybrid cholesteric LC structure. Unlike the situation in non-chiral hybrid molecular-colloidal LCs, where biaxial order emerges only at modest to high volume fractions of the anisotropic colloidal particles, above a uniaxial-biaxial transition concentration, the orientational probability distribution of colloidal inclusions immersed in chiral nematic hosts are unavoidably biaxial even at vanishingly low particle volume fractions. In addition, the colloidal inclusions induce local biaxiality in the molecular orientational order of the LC host medium, which enhances the weak biaxiality of the LC in a chiral nematic phase coming from the symmetry breaking caused by the presence of the helical axis. With the help of analytical modeling and computer simulations based on minimizing the Landau de Gennes free energy of the host LC around the colloidal inclusions, we explain our experimental findings and conclude that the biaxial order of chiral molecular-colloidal LCs is strongly enhanced as compared to both achiral molecular-colloidal LCs and molecular cholesteric LCs

关键词： Probability distributions

Stress-shape misalignment in confluent cell layers

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arXiv 2023年

作者： Nejad, Mehrana R. Ruske, Liam J. McCord, Molly Zhang, Jun Zhang, Guanming Notbohm, Jacob Yeomans, Julia M. The Rudolf Peierls Centre for Theoretical Physics Department of Physics University of Oxford Parks Road OxfordOX1 3PU United Kingdom Biophysics Program University of Wisconsin-Madison United States Department of Mechanical Engineering University of Wisconsin-Madison United States Department of Engineering Physics University of Wisconsin-Madison United States Center for Soft Matter Research Department of Physics New York University New York10003 United States Simons Center for Computational Physical Chemistry Department of Chemistry New York University New York10003 United States

This study investigates the relationship between cell shape and cell-generated stresses in confluent cell layers. Using simultaneous measurements of cell shape orientation and cell-generated contractile forces in MDCK and LP-9 colonies, we report the emergence of correlated, dynamic domains in which misalignment between the directors defined by cell shape and by contractile forces reaches up to 90o, effectively creating extensile domains in a monolayer of contractile cells. To understand this misalignment, we develop a continuum model that decouples the orientation of cell-generated active forces from the orientation of the cell shapes. This challenges the prevailing understanding that cells throughout a tissue create either contractile or extensile forces, and the validity of the usual active nematic models of cell motility where active forces are strictly slaved to cell shape orientation. © 2023, CC BY.

关键词： Cells