关键词：
open system;non-Markovianity;waveguide QED;quantum information
摘要：
We investigate the non-Markovianity (NM) of a waveguide QED with a two-level atom as the system and a semi-infinite rectangular waveguide as the environment, where the transverse magnetic (TM$_{mn}$) modes define the quantum channels of guided photons. The perfect mirror imposed by the finite end exerts a retarded feedback mechanism to allow for information backflow, which leads to NM dynamics. For the energy separation of the atom far away from the cutoff frequencies of transverse modes, the delay differential equations are obtained with single-excitation initial in the atom. Our attention is focused on the effects of multiple quantum channels involved in guiding photons on the degree of non-Markovian behavior. An asymptotic value of the non-Markovianity $\mathcal{N}_{1}$ can be found as the atom-mirror distance is large enough, however, the asymptotic value of $\mathcal{N}_{2}$ of the atom interacting with the effective double-modes is lower than that of the atom interacting with the effective single-mode. We also show that $\mathcal{N}_{1}$ is a constant, and the analytical expression for $\mathcal{N}_{2}$ is related to the parameters associated with the modes, which is related to the interference of the two modes.
作者机构：
[Shao Lin CHEN] College of Mathematics and Statistics,Hengyang Normal University,Hengyang 421002,P.R.China;[Shao Lin CHEN] Hunan Provincial Key Laboratory of Intelligent Information Processing and Application,Hengyang 421002,P.R.China;Department of Mathematics,Indian Institute of Technology Madras,Chennai-600 036,India;[Saminathan PONNUSAMY] 马德拉斯理工学院
通讯机构：
[Shao Lin Chen] C;College of Mathematics and Statistics, Hengyang Normal University, Hengyang, P. R. China<&wdkj&>Hunan Provincial Key Laboratory of Intelligent Information Processing and Application, Hengyang, P. R. China
关键词：
Harmonic K-quasiconformal mapping;Koebe type covering theorem;Koebe type distortion theorem;Radial John disk
关键词：
compact torus (CT);circuit modelling;nonlinear regression analysis (NRA);point Model
摘要：
Compact torus（CT） injection is one of the most promising methods for the central fuelling of next-generation reactor-grade fusion devices due to its high density, high velocity, and selfcontained magnetised structure. A newly compact torus injector（CTI） device in Keda Torus e Xperiment（KTX）, named KTX-CTI, was successfully developed and tested at the University of Science and Technology in China. In this study, first, we briefly introduce the basic principles and structure of KTX-CTI, and then, present an accurate circuit model that relies on nonlinear regression analysis（NRA） for studying the current waveform of the formation region. The current waveform, displacement, and velocity of CT plasma in the acceleration region are calculated using this NRA-based one-dimensional point model. The model results were in good agreement with the experiments. The next-step upgrading reference scheme of the KTX-CTI device is preliminarily investigated using this NRA-based point model. This research can provide insights for the development of experiments and future upgrades of the device.
摘要：
We study the entanglement dynamics of two atoms coupled to their own Jaynes–Cummings cavities in single-excitation space. Here, we use concurrence to measure atomic entanglement, and consider the Bell-like states to be initial states. Our analysis suggests that collapse and revival take place in entanglement dynamics. The physical mechanism behind entanglement dynamics is periodic information and energy exchange between atoms and light fields. For the initial Bell-like states,evolutionary periodicity of the atomic entanglement can only be found if the ratio of the two atom–cavity coupling strengths is a rational number. Also, whether there is a time translation between two kinds of initial Bell-like state depends on odd versus even numbers of the coupling-strength ratio.
通讯机构：
[Luo, X.-J.] S;[Tang, S.-L.] N;Nanjing National Laboratory of Microstructures, China;Shanghai Key Laboratory of Materials Protection and Advanced Materials in Electric PowerChina
关键词：
transport properties;molecular electronic devices;nonequilibrium Green's functions
摘要：
Dynamically controlling terahertz (THz) wavefronts in a designable fashion is highly desired in practice. However, available methods working at microwave frequencies do not work well in the THz regime due to lacking suitable tunable elements with submicrometer sizes. Here, instead of locally controlling individual meta-atoms in a THz metasurface, we show that rotating different layers (each exhibiting a particular phase profile) in a cascaded metadevice at different speeds can dynamically change the effective Jones-matrix property of the whole device, thus enabling extraordinary manipulations on the wavefront and polarization characteristics of a THz beam impinging on the device. After illustrating our strategy based on model calculations, we experimentally demonstrate two proof-of-concept metadevices, each consisting of two carefully designed all-silicon transmissive metasurfaces exhibiting different phase profiles. Rotating two metasurfaces inside the fabricated devices at different speeds, we experimentally demonstrate that the first metadevice can efficiently redirect a normally incident THz beam to scan over a wide solid-angle range, while the second one can dynamically manipulate both the wavefront and polarization of a THz beam. Our results pave the way to achieving dynamic control of THz beams, which is useful in many applications, such as THz radar, and bio- and chemical sensing and imaging.
作者机构：
[李浪; 冯景亚; 刘波涛; 郭影; 李秋萍] Hunan Provincial Key Laboratory of Intelligent Information Processing and Application, Hengyang Normal University, Hengyang;421002, China;College of Information Science and Engineering, Hunan Normal University, Changsha;410081, China;College of Computer Science and Technology, Hengyang Normal University, Hengyang
通讯机构：
[Jingya Feng] H;Hunan Provincial Key Laboratory of Intelligent Information Processing and Application, Hengyang Normal University, Hengyang, China<&wdkj&>College of Information Science and Engineering, Hunan Normal University, Changsha, China
摘要：
In this era of pervasive computing, low-resource devices have been deployed in various fields. PRINCE is a lightweight block cipher designed for low latency, and is suitable for pervasive computing applications. In this paper, we propose new circuit structures for PRINCE components by sharing and simplifying logic circuits, to achieve the goal of using a smaller number of logic gates to obtain the same result. Based on the new circuit structures of components and the best sharing among components, we propose three new hardware architectures for PRINCE. The architectures are simulated and synthesized on different programmable gate array devices. The results on Virtex-6 show that compared with existing architectures, the resource consumption of the unrolled, low-cost, and two-cycle architectures is reduced by 73, 119, and 380 slices, respectively. The low-cost architecture costs only 137 slices. The unrolled architecture costs 409 slices and has a throughput of 5.34 Gb/s. To our knowledge, for the hardware implementation of PRINCE, the new low-cost architecture sets new area records, and the new unrolled architecture sets new throughput records. Therefore, the newly proposed architectures are more resource-efficient and suitable for lightweight, latency-critical applications.
作者机构：
[Huang, Yanqing; Liu, Hongbo; Zhang, Dingzong] Hengyang Normal Univ, Coll Phys & Elect Engn, Hengyang 421008, Peoples R China.;[Yang, Cheng; Shen, Wei; Xiang, Nong; Hu, Youjun] Chinese Acad Sci, Inst Plasma Phys, Hefei 230031, Peoples R China.
通讯机构：
[Dingzong ZHANG] C;[Youjun HU] I;Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China<&wdkj&>College of Physics and Electronic Engineering, Hengyang Normal University, Hengyang 421008, People's Republic of China
关键词：
ion cyclotron resonance heating;the loss of fast ions;EAST
摘要：
The classical prompt loss of fast ions produced by minority ion cyclotron resonance heating(ICRH)is studied by a guiding center orbit following code in the Experimental Advanced Superconducting Tokamak(EAST).It is found that the loss of fast ions produced by ICRH mainly appears in both ends of the resonance layer,while the loss of fast ions in the middle resonance layer is very small.The dominant fast loss comes from trapped ions,rather than from passing ions.Controlling the location of resonance layer at the plasma core may be more beneficial to the EAST tokamak ICRH.In addition,the loss distribution of fast ions is studied.The results show that the fast ions are mainly lost near the midplane in the poloidal direction,but almost uniformly in the toroidal direction.Moreover,we investigate the dependence of fast ion loss on the ICRH power.The simulation results show that the loss fraction of fast ions in both ends of the resonance region increases with the ion cyclotron range of frequencies(ICRF)power,but barely affects the loss of fast ions in the middle region.
期刊：
Chinese Journal of Structural Chemistry,2021年40(12):1673-1679 ISSN：0254-5861
作者机构：
[张志坚; 谭宇星; 蒋伍玖] Key Laboratory of Functional Metal-organic Compounds of Hunan Province, Key Laboratory of Functional Organometallic Materials, University of Hunan Province, Hunan Provincial Engineering Research Center for Monitoring and Treatment of Heavy Metals Pollution in the Upper Reaches of Xiangjiang River, College of Chemistry and Materials Science, Hengyang Normal University;[南小龙] Nuclear Bureau of Hunan Province Nuclear Industry Brigade 306;[谭延亮] Hunan Provincial Engineering Research Center for Uranium Mineral Exploration Technology, College of Physics and Electronic Engineering, Hengyang Normal University
摘要：
Two UO_2~(2+) complexes {[C_5H_4N(O)C=N-N=C(Ph)-(Ph)C=N-N=C(O)-C_5H_4N]_2UO_2(CH_3OH)}(I) and {[C_5H_4N(O)C=N-N=C(Ph)-(Ph)C=N-N=C(O)-C_5H_4N]_2UO_2(C_5H_4N(O)C=N-NH_2)}(II) were synthesized and characterized by IR,elemental analysis and thermal stability analysis, and the crystal structures were determined by X-ray diffraction.The crystal of complex I belongs to monoclinic system, space group P2_1/n with a = 11.7678(4), b= 16.9667(6), c = 14.3051(5) A,β = 98.918(3)°, Z = 4, V = 2821.64(17) A~3, D_c = 1.837 Mg·m~(-3),µ(MoKa)= 5.805 mm~(-1), F(000) = 1504, R = 0.0346 and wR = 0.0688.The crystal of complex II is of triclinic system, space group P1 with a = 11.6417(5),b = 11.7297(5),c = 14.2197(5) A,α = 71.697(4)°,β=86.020(3)°, y = 71.572(4)°,Z = 2, V= 1748.02(12) A~3,D_c = 1.742 Mg·m~(-3), µ(MoKa) = 4.704 mm~(-1), F(000) = 894,R = 0.0283 and wR = 0.0537.The U1 is a seven-coordinate pentagonal bipyramidal configuration in I and an eight-coordinate hexagonal dipyramidal configuration in II.The thermal stability and quantum chemical calculations of I and II were also investigated.
作者机构：
Air and Missile Defense College,Air Force Engineering University,Xi'an 710051,China;Institute of Flexible Electronics,Northwestern Polytechnical University,Xi'an 710072,China;College of Physics and Electronic Engineering,Hengyang Normal University,Hengyang 421002,China;SDU Nano Optics,University of Southern Denmark,Campusvej 55,DK-5230 Odense,Denmark;School of Information and Communication Engineering,University of Electronic Science and Technology of China,Chengdu 611731,China
摘要：
Achieving full-polarization (σ) invisibility on an arbitrary three-dimensional (3D) platform is a long-held knotty issue yet extremely promising in real-world stealth applications.However,state-of-the-art invisibility cloaks typically work under a specific polarization because the anisotropy and orientation-selective resonant nature of artificial materials made the σ-immune operation elusive and terribly challenging.Here,we report a deterministic approach to engineer a metasurface skin cloak working under an arbitrary polarization state by theoretically synergizing two cloaking phase patterns required,respectively,at spin-up (σ +) and spin-down (σ –) states.Therein,the wavefront of any light impinging on the cloak can be well preserved since it is a superposition of σ + and σ – wave.To demonstrate the effectiveness and applicability,several proof-of-concept metasurface cloaks are designed to wrap over a 3D triangle platform at microwave frequency.Results show that our cloaks are essentially capable of restoring the amplitude and phase of reflected beams as if light was incident on a flat mirror or an arbitrarily predesigned shape under full polarization states with a desirable bandwidth of ~17.9%,conceiving or deceiving an arbitrary object placed inside.Our approach,deterministic and robust in terms of accurate theoretical design,reconciles the milestone dilemma in stealth discipline and opens up an avenue for the extreme capability of ultrathin 3D cloaking of an arbitrary shape,paving up the road for real-world applications.
作者机构：
[汪新文; 张慧敏; 刘珂; 刘延] College of Physics and Electronic Engineering, Hengyang Normal University, Hengyang;421002, China;Hunan Provincial Key Laboratory of Intelligent Information Processing and Application, Hengyang;[汪新文] 421002, China<&wdkj&>Hunan Provincial Key Laboratory of Intelligent Information Processing and Application, Hengyang;[汪新文; 张慧敏; 刘珂; 刘延] 421002, China
关键词：
pnictides and chalcogenides;properties of superconductors;effects of pressure;methods of materials synthesis and materials processing
摘要：
The origin of the ~40 and ~30 K superconducting phases in the metal-intercalated FeSe superconductors is still unclear. We report the synthesis of K0:3(NH3)y(FeSe1−xTex)2 and K0:6(NH3)y(FeSe1−xTex)2 with x=0-0.6 by using the liquid ammonia method at room temperature. The superconducting transition temperature Tc of the former remains about 43 K for all the nominal Te content less than 0.3, while that of the latter is about 30 K and obviously decreases with Te doping. Superconductivity disappears for x ≥0.4 in both systems. Except for the different chemical pressure induced by substitution of Te for Se in both systems, we also observed distinct external pressure effect on superconductivity for both systems, with much more efficiency of suppressing Tc by external pressure in the former system. These dramatic differences of both chemical and external pressure effects on Tc between the ~30 and ~40 K superconducting phases revealed that the existence of the two superconducting phases can be ascribed to the moderate and negligible coupling between FeSe layers, respectively.
作者机构：
[路飞平; 师应龙; 赵玉祥; 刘晓斌; 张明霞] Department of Physics, Tianshui Normal University, Tianshui;741000, China;[邓艳红] College of Physics and Electronics Engineering, Hengyang Normal University, Hengyang;421002, China;[路飞平; 师应龙; 赵玉祥; 刘晓斌; 张明霞] 741000, China
