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Preparation of pseudo-pure states for NMR quantum computing with one ancillary qubit

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Science China(Physics,Mechanics & Astronomy) 2019年第6期62卷 13-20页

作者： Tao Xin Liang Hao shi-yao Hou Guan-Ru Feng Gui-Lu Long State Key Laboratory of Low-dimensional Quantum Physics and Department of Physics Tsinghua University Shenzhen Institute for Quantum Science and Engineering Southern University of Science and Technology Center for Quantum Computing Peng Cheng Laboratory Shenzhen Key Laboratory of Quantum Science and Engineering Southern University of Science and Technology Institute of Applied Physics and Computational Mathematics Center for Computational Sciences Sichuan Normal University College of Physics and Electronic Engineering Sichuan Normal University Institute for Quantum Computing Waterloo Tsinghua National Laboratory of Information Science and Technology The Innovative Center of Quantum Matter

Quantum state preparation plays an equally important role as quantum operations and measurements in quantum information processing. The previous methods for initialization require either an exponential number of experiments, or cause signal reduction or place restrictions on molecular structures. In this study, we propose three types of quantum circuits for preparing the pseudo-pure states of(n-1) qubits in the n-coupled Hilbert space, which simply needs the assistance of one ancilla spin and two different experiments independent of n. Most importantly, our methods work well on homo-nuclear and hetero-nuclear molecules without the reduction of signals in the gradient field. As a proof-of-principle demonstration, we experimentally prepared the pseudo-pure states of heteronuclear 2-qubit and homonuclear 4-qubit molecules using a nuclear magnetic resonance quantum information processor.

关键词： quantum state preparation nuclear magnetic resonance quantum algorithms

Microstructure evolution in grey cast iron during directional solidification

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International Journal of Minerals,Metallurgy and Materials 2017年第8期24卷 884-890页

作者： Xian-fei Ding Xiao-zheng Li Qiang Feng Warkentin Matthias shi-yao Huang National Center for Materials Service Safety University of Science and Technology Beijing Beijing Key Laboratory of Special Melting and Preparation of High-end Metal University of Science and Technology Beijing State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Ford Research & Advanced Engineering Europe Materials and Process Research Ford Motor Research and Engineering Center

The solidification characteristics and microstructure evolution in grey cast iron were investigated through Jmat-Pro simulations and quenching performed during directional solidification. The phase transition sequence of grey cast iron was determined as L → L + γ→ L + γ + G →γ + G → P(α + Fe_3C) + α + G. The graphite can be formed in three ways: directly nucleated from liquid through the eutectic reaction(L →γ + G), independently precipitated from the oversaturated γ phase(γ→γ + G), and produced via the eutectoid transformation(γ→ G + α). The area fraction and length of graphite as well as the primary dendrite spacing decrease with increasing cooling rate. Type-A graphite is formed at a low cooling rate, whereas a high cooling rate results in the precipitation of type-D graphite. After analyzing the graphite precipitation in the as-cast and transition regions separately solidified with and without inoculation, we concluded that, induced by the inoculant addition, the location of graphite precipitation changes from mainly the γ interdendritic region to the entire γ matrix. It suggests that inoculation mainly acts on graphite precipitation in the γ matrix, not in the liquid or at the solid–liquid front.

关键词： directional solidification grey cast iron phase transition graphite

An Active Optical Multi-channel Switch

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Chinese Physics Letters 1999年第10期16卷 734-736页

作者： GU Guo-chang ZHU shi-yao WU Xiang CHEN Hong Department of Physics Tongji UniversityShanghai 200092 Department of Physics Hong Kong Baptist UniversityHong Kong

We present the theoretical results on using the spontaneous emission which is induced from a two-level atom embedded in a photonic crystal with two bands and one forbidden *** is shown that the emission field from the atom is composed of two parts,one is a localized field,which always exists,and the other is one or two propagating *** emission of the propagating mode depends on the gap size and the relative position of the upper-level of the atom with respect to the edges of the two *** propagating modes have a sudden jump from zero to a certain value when the gap or the related position of the upper level *** jump can be used to design an active optical two-channel or four-channel *** to the localizedfield being within a few dozen atoms,the switch can be designed in a few micrometers.

关键词： propagating bands forbidden

Characterization of dissolved organic matter distribution in forestland and farmland of mollisol based on untargeted metabolomics

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Soil Ecology Letters 2023年第4期5卷 89-99页

作者： shi yao Yongrong Bian Xin Jiang Yang Song Key Laboratory of Soil Environment and Pollution Remediation Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China University of Chinese Academy of Sciences Beijing 100049China

●Characterization of mollisol soil DOM by untargeted metabolomics is possible.●The polarity of the extractants determines the polarity of the extracted DOM.●Land use patterns affect the biological functions and co-network interaction of *** soil is a major contributor to food *** of the molecular characteristics of dissolved organic matter(DOM)will contribute to the overall understanding and management of mollisol ***,the complexity of DOM poses a challenge to understanding its molecular *** this study,we investigated the molecular characteristics of DOM(<1000 Da)in mollisol soils with different soil use patterns(forestland and dryland)based on untargeted ***,we confirmed the feasibility of untargeted metabolomics for the molecular characterization of DOM in mollisol *** in forestland is mainly derived from plant metabolites,and DOM can perform more biological ***,DOM in dryland has complex composition and has powerful co-occurrence network interactions due to human *** has better extraction efficiency for polar DOM,while organic reagents can efficiently extract lipid-like DOM,but the polarity of the extractant has less influence on the DOM than the soil physicochemical ***,14-dihydroxyzeatin screened based on metabolomics can be used as a potential indicator for corn ***,untargeted metabolomics can be an effective method to characterize the DOM molecules of mollisol soil,which provides new insights for management of mollisol soil and sustainable agricultural development.

关键词： dissolved organic.matter mollisol soil metabolomics molecular identification

Effects of nano-sized Ag reinforcing particulates on the microstructure of Sn-0.7Cu solder joints

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International Journal of Minerals,Metallurgy and Materials 2009年第6期16卷 677-684页

作者： Feng Tai Fu Guo Zhi-dong Xia Yong-ping Lei yao-wu shi College of Materials Science and Engineering Beijing University of Technology Beijing 100124 China

Composite solders were prepared by mechanically dispersing different volumes of nano-sized Ag particles into the Sn-0.7Cu eutectic solder. The effects of Ag particle addition on the microstructure of Sn-0.7Cu solder joints were investigated. Besides, the effects of isothermal aging on the microstructural evolution in the interfacial intermetallic compound （IMC） layer of the Sn-0.7Cu solder and the composite solder reinforced with 1vol% Ag particles were analyzed, respectively. Experimental results indicate that the growth rate of the interfacial IMC layer in the Ag particles reinforced composite solder joint is much lower than that in the Sn-0.7Cu solder joint during isothermal aging. The Ag particles reinforced composite solder joint exhibits much lower layer-growth coefficient for the growth of the IMC layer than the corresponding solder joint.

关键词： lead-free solder composite solder intermetallic compounds microstructure isothermal aging

Teleported State and Its Fidelity in Quantum Teleportation of Continuous Variables

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Chinese Physics Letters 2003年第1期20卷 14-17页

作者： Li Fu-Li Li Hong-Rong Zhang Jun-Xiang Zhu shi-yao Department of Applied Physics Xian Jiaotong University Xi'an 710049 Institute of Opto-Electronics Shanxi University Taiyuan 030006 Department of Physics Hong Kong Baptist University Hong Kong

When given an unknown quantum state which may be either a pure or a mixed state in the coherent state representation, we show that explicit expressions for the teleported state and its fidelity in the teleportation process (S. L. Braunstein and H. J. Kimble 1998 Phys. Rev. Lett. 80 869) can be obtained without explicit expansions for the two-mode squeezed vacuum state and the Bell basis in a specified representation.

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Generating large steady-state optomechanical entanglement by the action of Casimir force

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Science China(Physics,Mechanics & Astronomy) 2014年第12期57卷 2276-2284页

作者： NIE Wen Jie LAN Yue Heng LI Yong ZHU shi yao Department of Physics Tsinghua University Beijing Computational Science Research Center Department of Applied Physics East China Jiaotong University

In this paper, we study an optomechanical device consisting of a Fabry-P6rot cavity with two dielectric nanospheres trapped near the cavity mirrors by an external driving laser. In the condition where the distances between the nanospheres and cavity mirrors are small enough, the Casimir force helps the optomechanical coupling to induce a steady-state optomechanical entanglement of the mechanical and optical modes in a certain regime of parameters. We investigate in detail the dependence of the steady- state optomechanical entanglement on external control parameters of the system, i.e., the effective detuning, the pump powers of the cavity, the cavity decay rate and the wavelength of the driving field. It is found that the large steady-state optomechanical entanglement, i.e. EN = 5.76, can be generated with experimentally feasible parameters, i.e. the pump power P = 18.2 μW, the cavity decay rate K = 0.5 MHz and the wavelength of the laser AL=1064 nm, which should be checked by optical measurement.

关键词： optomechanics Casimir effect entanglement

Optimization of catalyst pellet structures and operation conditions for CO methanation

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Chinese Journal of Chemical Engineering 2021年第12期34卷 106-113页

作者： Yiquan Zhao yao shi Guanghua Ye Jing Zhang Xuezhi Duan Gang Qian Xinggui Zhou State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China

A fundamental understanding of the effects of catalyst pellet structures and operation conditions on catalytic performance is crucial for the reactions limited by diffusion mass transfer. In this work, a numerical investigation has been carried out to understand the effect of catalyst pellet shapes(sphere, cylinder, trilobe and tetralobe) on the reaction-diffusion behaviors of CO methanation. The results reveal that the poly-lobe pellets with larger external specific surface area have shorter diffusion path, and thus result in higher effectiveness factors and CO conversion rates in comparison with the spherical and cylindrical pellets. The effects of operating conditions and pore structures on the trilobular catalyst pellet with high performance are further probed. Though lower temperature can contribute to larger effectiveness factors of pellets, it also brings about lower reaction rates, and pressure has little impact on the effectiveness factors of the pellets. The increase in porosity can reduce the pellet internal diffusion limitations effectively and there exists an optimal porosity for the methanation reaction. Finally, the height of the trilobular pellet is optimized under the given geometric volume, and the results demonstrate that the higher the trilobular catalyst, the better the reaction performance within the allowable mechanical strength range.

关键词： CO methanation Numerical simulation Catalyst pellet Shape effects Reaction-diffusion behavior

Backstepping Stabilization Control for MIMO Nonlinear Differential-Algebraic Equations Subsystem and its Applications 36

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Backstepping Stabilization Control for MIMO Nonlinear Differ...