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Substrate integrated waveguide filter with improved stopband performance using LTCC technology

Progress In Electromagnetics Research C 2014年 54卷 155-162页

作者： Zhang, Ping-Juan Li, Min-Quan College of Mathematics Physics and Information Engineering Anhui Science and Technology University Chuzhou233100 China Key Laboratory of Intelligent Computation and Signal Processing Ministry of Education Anhui University Hefei230039 China

A novel multi-layer third-order substrate integrated waveguide (SIW) bandpass filter with improved lower stopband performance is proposed. TE201-mode in folded-SIW cavity is utilized to implement negative cross coupling, and the TE101-mode is taken as a non-resonating node (NRN) for implementing bypass coupling. A circular aperture etched on the middle metal layer is used to realize coupling between source and the second SIW cavity. Then, three transmission zeros located below the passband can be obtained to improve stopband attenuation. Meanwhile, better spurious suppression performance above passband is achieved. A filter sample is designed and fabricated with multi-layer low-temperature co-fired ceramic (LTCC) technology. The measured S-parameters agree well with the simulated ones, with its predicted good performance. © 2014 Electromagnetics Academy. All rights reserved.

关键词： Substrate integrated waveguides

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x-dependence reconstruction of pion and kaon PDFs from Mellin moments author 38

x-dependence reconstruction of pion and kaon PDFs from Melli...

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38th International Symposium on Lattice Field Theory, LATTICE 2021

作者： Alexandrou, Constantia Bacchio, Simone Cloët, Ian Constantinou, Martha Hadjiyiannakou, Kyriakos Koutsou, Giannis Lauer, Colin Department of Physics University of Cyprus P.O. Box 20537 Nicosia1678 Cyprus Computation-Based Science and Technology Research Center The Cyprus Institute 20 Kavafi Str. Nicosia2121 Cyprus Physics Division Argonne National Laboratory LemontIL60439 United States Department of Physics Temple University 1925 N. 12th Street PhiladelphiaPA19122-1801 United States

We present a calculation of the connected-diagram contributions to the first three non-trivial Mellin moments for the pion and kaon, extracted using local operators with up to 3 covariant derivatives. We use one ensemble of gauge configurations with two degenerate light, a strange and a charm quark (Nf =2+1+1) of maximally twisted mass fermions with clover improvement. The ensemble has a pion mass ∼260 MeV, and a kaon mass ∼530 MeV. We reconstruct the x-dependence of the PDFs via fits to our results, and find that our lattice data favor a (1 − x)2-behavior in the large-x region for both the pion and kaon PDFs. We integrate the reconstructed PDFs to extract the higher moments, hxni, with 4 ≤ n ≤ 6. Finally, we compare the pion and kaon PDFs, as well as the ratios of their Mellin moments, to address the effect of SU(3) flavor symmetry breaking. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0)

关键词： Hadrons

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Observing Er3+ Sites in Si With an In Situ Single-Photon Detector

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Physical Review Applied 2023年第1期19卷 014037-014037页

作者： Ian R. Berkman Alexey Lyasota Gabriele G. de Boo John G. Bartholomew Brett C. Johnson Jeffrey C. McCallum Bin-Bin Xu Shouyi Xie Rose L. Ahlefeldt Matthew J. Sellars Chunming Yin Sven Rogge Centre of Excellence for Quantum Computation and Communication Technology School of Physics University of New South Wales Sydney NSW 2052 Australia Centre for Engineered Quantum Systems School of Physics The University of Sydney Sydney NSW 2006 Australia The University of Sydney Nano Institute The University of Sydney Sydney NSW 2006 Australia Centre of Excellence for Quantum Computation and Communication Technology School of Physics University of Melbourne Victoria 3010 Australia Centre of Excellence for Quantum Computation and Communication Technology School of Engineering RMIT University Victoria 3001 Australia Centre of Excellence for Quantum Computation and Communication Technology Research School of Physics Australian National University Canberra ACT 0200 Australia CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences University of Science and Technology of China Hefei 230026 China

We present a flexible method to study the optical properties of an Er3+ ensemble in Si accessed via resonant excitation and in situ single-photon detection. The technique allows an efficient resonant photoluminescence detection of optically active centers with weak oscillator strength in transparent crystals without the need for nanofabrication on the sample. We observe 70 Er3+ resonances in Si, of which 62 resonances have not been observed in the literature, with optical lifetimes ranging from 0.5 to 1.5 ms. We observe inhomogeneous broadening of less than 400 MHz and an upper bound on the homogeneous linewidth of 0.75 and 1.4 MHz for two separate resonances. These narrow, stable resonances confirm Er3+ in Si as a promising quantum information candidate. We discuss the use of this technique for rapid characterization of future samples, with the aim of enhancing the prevalence of sites which are favorable for quantum information applications.

关键词： Luminescence Nanophotonics Optical quantum information processing Quantum information with hybrid systems Single photon sources Doped semiconductors Rare-earth doped crystals Photoluminescence

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Elemental noncentrosymmetric superconductors

arXiv

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arXiv 2024年

作者： Zhang, Hu Research Center for Computational Physics of Hebei Province Hebei Key Laboratory of High-precision Computation and Application of Quantum Field Theory College of Physics Science and Technology Hebei University Baoding071002 China

Superconductivity has been discovered in many materials including elements, cuprates and nickelates. Noncentrosymmetric superconductors get attention due to their physical properties results from spatial inversion symmetry breaking. Here we propose the existence of elemental noncentrosymmetric superconductors which needs to break spatial inversion symmetry in single element phases realized by occupations of more than one Wyckoff positions. Elemental noncentrosymmetric superconductors allow us to study the admixture of spin-singlet and spin-triplet pairing states in elements with simple crystal structures and chemical conditions. We find that four-layer La thin films coming from bulk α-La with a double hexagonal close-packed structure are elemental noncentrosymmetric superconductors since the dimension reduction breaks the spatial inversion symmetry. In the normal state, four-layer La is a polar rare-earth metal with a spontaneous polarization having a polar layer group like ferroelectrics. Hence, to be more precise, four-layer La can also be called the elemental polar superconductor in the superconductivity state. Based on this method of breaking inversion symmetry, we discovery polar rare-earth metals, polar transition metals, polar alkali metals and polar alkali earth metals. Other candidate materials are bulk polar materials formed with group 15 elements, Bi thin films with polar stacking, polar double layer plumbene and Al thin films. The question of building the periodic table of elemental noncentrosymmetric superconductors is raised. © 2024, CC BY.

关键词： Rare earths

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Sparse Representations, Inference and Learning

arXiv

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arXiv 2023年

作者： Lauditi, Clarissa Troiani, E. Mézard, M. Department of Applied Science and Technology Politecnico di Torino Italy Statistical Physics of Computation Laboratory EPFL Switzerland Department of Computing Sciences Bocconi University Milano Italy

In recent years statistical physics has proven to be a valuable tool to probe into large dimensional inference problems such as the ones occurring in machine learning. Statistical physics provides analytical tools to study fundamental limitations in their solutions and proposes algorithms to solve individual instances. In these notes, based on the lectures by Marc Mézard in 2022 at the summer school in Les Houches, we will present a general framework that can be used in a large variety of problems with weak long-range interactions, including the compressed sensing problem, or the problem of learning in a perceptron. We shall see how these problems can be studied at the replica symmetric level, using developments of the cavity methods, both as a theoretical tool and as an algorithm. Copyright © 2023, The Authors. All rights reserved.

关键词： Statistical physics

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Tensor rank of the tripartite state |W〉⊗n

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Physical Review A 2010年第1期81卷 014301-014301页

作者： Nengkun Yu Eric Chitambar Cheng Guo Runyao Duan State Key Laboratory of Intelligent Technology and Systems Tsinghua National Laboratory for Information Science and Technology Department of Computer Science and Technology Tsinghua University Beijing 100084 China and Centre for Quantum Computation and Intelligent Systems (QCIS) Faculty of Engineering and Information Technology University of Technology Sydney New South Wales 2007 Australia Physics Department University of Michigan 450 Church Street Ann Arbor Michigan 48109-1040 USA

Tensor rank refers to the number of product states needed to express a given multipartite quantum state. Its nonadditivity as an entanglement measure has recently been observed. In this Brief Report, we estimate the tensor rank of multiple copies of the tripartite state |W〉=13(|100〉+|010〉+|001〉). Both an upper bound and a lower bound of this rank are derived. In particular, it is proven that the rank of |W〉⊗2 is 7, thus resolving a previously open problem. Some implications of this result are discussed in terms of transformation rates between |W〉⊗n and multiple copies of the state |GHZ〉=12(|000〉+|111〉).

关键词： Tensors

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Locally indistinguishable subspaces spanned by three-qubit unextendible product bases

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Physical Review A 2010年第3期81卷 032329-032329页

作者： Runyao Duan Yu Xin Mingsheng Ying Centre for Quantum Computation and Intelligent Systems (QCIS) Faculty of Engineering and Information Technology University of Technology Sydney New South Wales 2007 Australia State Key Laboratory of Intelligent Technology and Systems Tsinghua National Laboratory for Information Science and Technology Department of Computer Science and Technology Tsinghua University Beijing 100084 People's Republic of China Computer Science and Artificial Intelligence Laboratory Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA Department of Physics Tsinghua University Beijing 100084 People's Republic of China

We study the local distinguishability of general multiqubit states and show that local projective measurements and classical communication are as powerful as the most general local measurements and classical communication. Remarkably, this indicates that the local distinguishability of multiqubit states can be decided efficiently. Another useful consequence is that a set of orthogonal n-qubit states is locally distinguishable only if the summation of their orthogonal Schmidt numbers is less than the total dimension 2n. Employing these results, we show that any orthonormal basis of a subspace spanned by arbitrary three-qubit orthogonal unextendible product bases (UPB) cannot be exactly distinguishable by local operations and classical communication. This not only reveals another intrinsic property of three-qubit orthogonal UPB but also provides a class of locally indistinguishable subspaces with dimension 4. We also explicitly construct locally indistinguishable subspaces with dimensions 3 and 5, respectively. Similar to the bipartite case, these results on multipartite locally indistinguishable subspaces can be used to estimate the one-shot environment-assisted classical capacity of a class of quantum broadcast channels.

关键词： Quantum computers

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构建准层状自空穴掺杂SnSe取向薄膜获得优异热电功率因子和输出功率密度

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science Bulletin 2023年第22期68卷 2769-2778,M0005页

作者：薛宇利王晴高志钱鑫王江龙闫国英陈明敬赵立东王淑芳李志亮 Hebei Key Laboratory of Optic-Electronic Information and Materials Key Laboratory of High-Precision Computation and Application of Quantum Field Theory of Hebei ProvinceCollege of Physics Science and TechnologyHebei UniversityBaoding 071002China School of Materials Science and Engineering Beihang UniversityBeijing 100191China Engineering Research Center of Zero-Carbon Energy Buildings and Measurement Techniques Ministry of EducationHebei UniversityBaoding 071002China

热电技术可以实现热能与电能的相互转换,其开发利用对于缓解能源危机具有重要意义.近10年来,SnSe因其潜在的高能量转换效率、绿色环保和低成本特性而备受关注.但SnSe的固有载流子浓度低(约10~(17)cm^(-3)),导致其功率因子偏低,从而限制... 详细信息

热电技术可以实现热能与电能的相互转换,其开发利用对于缓解能源危机具有重要意义.近10年来,SnSe因其潜在的高能量转换效率、绿色环保和低成本特性而备受关注.但SnSe的固有载流子浓度低(约10~(17)cm^(-3)),导致其功率因子偏低,从而限制了SnSe基器件的输出功率密度.因此,探索新的载流子浓度优化策略对于SnSe的应用至关重要.此外,与三维块体相比,二维薄膜更易和现代半导体工艺相兼容,在热电微纳米器件的构筑和应用方面具有独特优势.本文报道了一种利用非原位硒化技术,通过电荷转移和自空穴掺杂效应来优化a轴取向SnSe基薄膜的载流子浓度.当硒化时间为20 min时,薄膜载流子浓度可提高至10~(18)cm^(-3)数量级,形成了准层状的自空穴掺杂SnSe基薄膜,其功率因子在600 K时达到了5.9μW cm^(-1)K^(-2).由硒化处理的SnSe基取向薄膜构筑的热电发电机在50和90 K的温差下分别具有约83、838μW cm^(-2)的超高功率密度.非原位硒化技术可以有效提高SnSe基薄膜的载流子浓度,为其他热电材料性能优化提供了一种新策略.

关键词： Thermoelectric property Thin film Tin selenide Post-selenization Carrier concentration

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Nickel Single Atoms/Cerium Oxide Hybrid for Hydrogen Production Via Solar-Heating Catalytic Dehydrogenation of Methyl Cyclohexane

SSRN

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SSRN 2022年

作者： Lv, Cuncai Lou, Pingping Chang, Jiarong Wang, Ruining Gao, Linjie Li, Yaguang Key Laboratory of High-precision Computation Application of Quantum Field Theory of Hebei Province Institute of Life Science and Green Development The College of Physics Science and Technology Hebei University Baoding071002 China

Methylcyclohexane (MCH)-toluene-hydrogen cycle can realize the recycling of matter and energy, owning a wide foreground in industrial application. The MCH dehydrogenation process is highly endothermic, and a heating temperature is needed to stimulate this reaction. The combination of thermal catalytic reactor and solar-to-heat system can realize solar-heating catalytic MCH dehydrogenation reaction. Whereas, such a highly desirable advanced system has not yet been reported. In this study, a hybrid of single-atom nickel anchored on cerium oxide nanosheets (Ni SA/CeO2 NS) has been constructed successfully. The hybrid exhibits remarkable thermal catalytic activity in MCH dehydrogenation, owning an H2 generation rate of 2756 mmol g-1 h-1 at 400 °C. The stepwise MCH dehydrogenation mechanism on the hybrid is investigated via density functional theory calculations. Moreover, we have developed a novel type of solar-to-heat equipment based on Ti2O3 thin film/Cu. Based on this device and the Ni SA/CeO2 NS hybrid, a solar-heating catalysis mode has been developed, with the H2 generation rates of 404 and 2604 mmol g-1 h-1 from MCH dehydrogenation under 1 and 2 kW m-2, respectively. This strategy provides the possibility to realize scalable MCH dehydrogenation under solar irradiation without secondary energy input. © 2022, The Authors. All rights reserved.

关键词： Dehydrogenation

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Mean-field embedding of the dual-fermion approach for correlated electron systems

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Physical Review E 2013年第6期88卷 063306-063306页

作者： S.-X. Yang H. Terletska Z. Y. Meng J. Moreno M. Jarrell Department of Physics and Astronomy Louisiana State University Baton Rouge Louisiana 70803 USA Center for Computation and Technology Louisiana State University Baton Rouge Louisiana 70803 USA Condensed Matter Physics and Materials Science Department Brookhaven National Laboratory Upton New York 11973 USA

To reduce the rapidly growing computational cost of the dual-fermion lattice calculation with increasing system size, we introduce two embedding schemes. One is the real fermion embedding, and the other is the dual-fermion embedding. Our numerical tests show that the real fermion and dual-fermion embedding approaches converge to essentially the same result. The application on the Anderson disorder and Hubbard models shows that these embedding algorithms converge more quickly with system size as compared to the conventional dual-fermion method, for the calculation of both single- and two-particle quantities.

关键词： FERMIONS RESEARCH HUBBARD model ENERGY-band theory of solids ANDERSON model ELECTRIC conductivity CONDUCTION band LATTICE theory STATISTICAL physics

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