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atom interferometers with weak-measurement path detectors and their quantum mechanical analysis

Chinese Physics B 2019年第6期28卷 45-65页

作者： Zhi-Yuan Li College of Physics and Optoelectronics South China University of TechnologyGuangzhou 510641China

According to the orthodox interpretation of quantum physics, wave-particle duality(WPD) is the intrinsic property of all massive microscopic particles. All gedanken or realistic experiments based on atom interferometers(AI) have so far upheld the principle of WPD, either by the mechanism of the Heisenberg’s position-momentum uncertainty relation or by quantum entanglement. In this paper, we propose and make a systematic quantum mechanical analysis of several schemes of weak-measurement atom interferometer(WM-AI) and compare them with the historical schemes of strongmeasurement atom interferometer(SM-AI), such as Einstein’s recoiling slit and Feynman’s light microscope. As the critical part of these WM-AI setups, a weak-measurement path detector(WM-PD) deliberately interacting with the atomic internal electronic quantum states is designed and used to probe the which-path information of the atom, while only inducing negligible perturbation of the atomic center-of-mass motion. Another instrument that is used to directly interact with the atomic center-of-mass while being insensitive to the internal electronic quantum states is used to monitor the atomic centerof-mass interference pattern. Two typical schemes of WM-PD are considered. The first is the micromaser-cavity path detector, which allows us to probe the spontaneously emitted microwave photon from the incoming Rydberg atom in its excited electronic state and record unanimously the which-path information of the atom. The second is the optical-lattice Bragg-grating path detector, which can split the incoming atom beam into two different directions as determined by the internal electronic state and thus encode the which-path information of the atom into the internal states of the atom. We have used standard quantum mechanics to analyze the evolution of the atomic center-of-mass and internal electronic state wave function by directly solving Schr¨odinger’s equation for the composite atom-electron-photon system in the

关键词： wave-particle duality atom interferometers weak-measurement path-detector quantum entanglement Heisenberg’s uncertainty relation

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atom Probe Tomography Study of Fe Segregation at Phase Interface in Zr–2.5Nb Alloy

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Acta Metallurgica Sinica(English Letters) 2019年第10期32卷 1281-1286页

作者： Xue Liang Qiang Li Jiao Huang Mei-Yi Yao Hui Li Qing-Dong Liu Institute of Materials Shanghai University Shanghai 200072 China Laboratory for Microstructures Shanghai University Shanghai 200444 China School of Materials Science and Engineering Inner Mongolia University of Technology Hohhot 010051. China School of Nuclear Science and Engineering Shanghai Jiaotong University Shanghai 200240 China

β-Nb is a typical second phase in Zr-Nb-based alloys used as fuel claddings in water-cooled nuclear reactors. The segregation of alloying element Fe may affect the corrosion resistance of Zr-Nb-based alloys. In this work, the Fe segregation at the interface between β-Nb phase and a-Zr matrix in Zr-2.5Nb alloy was studied using atom probe tomography and focused ion beam. The results suggested that the Fe concentration was much lower than Nb concentration in a-Zr matrix, while Fe selectively segregated at the β-Nb/a-Zr phase interface, leading to a Fe concentration peak at some interfaces. The peak Fe concentration varied from 0.4 to 1.2 at.% and appeared at the position where Zr concentration was approximately equal to Nb concentration. The selective segregation of Fe should be affected by the heat treatment and structure defects induced by cold rolling.

关键词： Zr-Nb alloy β-Nb phase Phase interface Segregation atom probe tomography

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Entanglement transfer via the Raman atom-cavity-field interaction

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Chinese Physics B 2010年第9期19卷 399-406页

作者：梁麦林袁兵 Physics Department School of ScienceTianjin University

For the Raman interaction between an atom and a two-mode cavity field prepared in the state ｜01〉 or ｜10〉, the atom and the field can be disentangled periodically. Such a property of Raman atom-field interaction allows the full entanglement transfer among many atoms and bimodal cavities. In the calculations, each atom is assumed to interact with its own cavity at a different time and so non-identical atoms can be treated conveniently. Entanglement sudden death is discussed too. Though atom-field interaction greatly changes the values of the concurrence for two atoms, configuration of the concurrence is almost not affected. When there is entanglement sudden death, atoms and cavities can still be entangled with one another. However, full entanglement transfer cannot be achieved for such systems with Raman atom-field interaction.

关键词： quantum information entanglement entanglement transfer atom

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Metal organic frameworks derived single atom catalysts for electrocatalytic energy conversion

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Nano Research 2019年第9期12卷 2067-2080页

作者： Tingting Sun Lianbin Xu Dingsheng Wang Yadong Li Department of Chemistry Tsinghua UniversityBeijing 100084China State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing 100029China

The development of efficient and cost-effective catalysts to catalyze a wide variety of electrochemical reactions is key to realize the large-scale applicati on of ren ewable and clean en ergy tech no *** to the maximum atom-utilization efficie ncy and unique electronic and geometric structures,single atom catalysts(SACs)have exhibited superior performance in various catalytic ***,assembled from the function alized orga nic lin kers and metal no des,metal-organic frameworks(MOFs)with ultrafi ne porosity have received treme ndous attention as precursors or self-sacrificing templates for preparing porous ***,the recent advances toward the synthesis strategies for using MOF precursors/templates to con struct SACs are systematically summarized with special emphasis on the types of central metal *** electrochemical applications of these recently emerged MOF-derived SACs for various energy-conversion processes,such as oxygen reduction/evolution reaction(ORR/OER),hydrogen evolution reaction(HER),and CO2 reduction reaction(CO2RR),are also discussed and *** ally,the curre nt challe nges and prospects regardi ng the developme nt of MOF-derived SACs are proposed.

关键词： single atom catalysts metal organic frameworks electrocatalytic energy conversion

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A general bimetal-ion adsorption strategy to prepare nickel single atom catalysts anchored on graphene for efficient oxygen evolution reaction

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Journal of Energy Chemistry 2020年第4期29卷 52-57页

作者： Yingqi Xu Weifeng Zhang Yaguang Li Pengfei Lu Zhong-Shuai Wu Hebei Key Lab of Optic-electronic Information and Materials The College of Physics Science and TechnologyHebei UniversityBaoding 071002HebeiChina Dalian National Laboratory for Clean Energy Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina

Single-atom catalysts (SACs) supported on two-dimensional (2D) materials are highly attractive for maximizing their catalytic ***,graphene based SACs are primarily bonded with nitrogen and carbon sites,resulting in poor performance for the oxygen evolution reaction (OER).Herein,we develop a general bimetal-ion adsorption strategy for the synthesis of individually dispersed Ni SACs anchored on the oxygenated sites of ultrathin reduced graphene oxide as efficient OER *** resultant Ni SACs for OER in alkaline electrolyte exhibit a highly stable overpotential of 328 mV at the current density of 10 mA cm^-2,and Tafel slope of 84 mV dec^-1 together with long-term durability and negligible degradation for 50 h,which is greatly outperform its counterparts of nitrogen bonded Ni SACs (564 mV,364 mV dec^-1) and Ni(OH)2 nanoparticles anchored on graphene (450 mV,142 mV dec^-1),and most reported Ni based OER ***,the extended X-ray absorption fine structure at the Ni K-edge and theoretical simulation reveal that the nickel-oxygen coordination significantly boost OER ***,this work will open numerous opportunities for creating novel-type 2D SACs via oxygen-metal bonding as highly robust OER catalysts.

关键词： Single atom catalyst Nickel Graphene Oxygen evolution reaction Electrocatalysts

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Turning ZrTe_5 into a semiconductor through atom intercalation

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Science China(Physics,Mechanics & Astronomy) 2019年第6期62卷 102-107页

作者： QiYuan Li YangYang Lv JingHui Wang Song Bao Wei Shi Li Zhu WeiMin Zhao ChengLong Xue ZhenYu Jia LiBo Gao YanBin Chen JinSheng Wen YanFeng Chen ShaoChun Li National Laboratory of Solid State Microstructures School of Physics Nanjing University National Laboratory of Solid State Microstructures Department of Materials Science and Engineering Nanjing University Collaborative Innovation Center of Advanced Microstructures Nanjing University

In this study we successfully intercalated potassium(K) atoms into single ZrTe_5 crystals by liquid ammonia method, and found a semimetal-to-semiconductor transition at low temperatures in K-intercalated ZrTe_5. As the K concentration increased, the resistance anomalous peak was gradually suppressed until finally disappearing. Whilst, the corresponding Hall resistance measurements consistently showed a sign reversal. The semimetal-to-semiconductor transition can be attributed to a lattice expansion induced by atom intercalation, leading to a larger energy band gap.

关键词： ZrTe5 atom intercalation topological insulator magnetoresistance Hall resistance

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Solute Clusters/Enrichment at the Early Stage of Ageing in Mg-Zn-Gd Alloys Studied by atom Probe Tomography

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Acta Metallurgica Sinica(English Letters) 2019年第2期32卷 187-193页

作者： Xin-Fu Gu Tadashi Furuhara Leng Chen Ping Yang School of Materials Science and Engineering University of Science and Technology Beijing Institute for Materials Research Tohoku University

Three-dimensional distribution of solute elements in an Mg–Zn–Gd alloy during ageing process is quantitatively characterized by three-dimensional atom probe(3DAP) tomography. Based on the radius distribution function, it is found that Zn–Gd solute pairs in Mg matrix appear mainly at two peaks at early stage of ageing, and the separation distance between Zn and Gd atoms could be well rationalized by the first-principle calculation. Moreover, the fraction of Zn–Gd solute pairs increases first and then decreases due to the precipitation of long-period stacking ordered(LPSO) structures. Both the composition of the structural unit in LPSO structure and the solute enrichment around it are quantified. It is found that Zn and Gd elements are synchronized in the LPSO structure, and solute segregation of pure Zn or Gd is not observed at the transformation front of the LPSO structure in this alloy. In addition, the crystallography of transformation front is further determined by 3DAP data.

关键词： Magnesium alloy Long-period stacking ordered(LPSO) atomic cluster Three-dimensional atom probe(3DAP) Crystallography

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Re effects in model Ni-based superalloys investigated with first-principles calculations and atom probe tomography

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Chinese Physics B 2020年第4期29卷 232-241页

作者： Dianwu Wang Chongyu Wang Tao Yu Wenqing Liu Central Iron and Steel Research Institute Beijing 100081China Department of Physics Tsinghua UniversityBeijing 100084China Key Laboratory for Microstructures Shanghai UniversityShanghai 200444China

The phase partition and site preference of Re atoms in a ternary Ni-Al-Re model alloy,including the electronic structure of different Re configurations,are investigated with first-principles calculations and atom probe *** Re distribution of single,nearest neighbor(NN),next-nearest neighbor(NNN),and cluster configurations are respectively designed in the models withγandγ*** results show that the Re atoms tend to enteringγphase and the Re atoms prefer to occupy the Al sites inγ*** Re cluster with a combination of NN and NNN Re-Re pair configuration is not preferred than the isolated Re atom in the Ni-based superalloys,and the configuration with isolated Re atom is more preferred in the ***,the electronic states are analyzed and the energetic parameters are *** electronic structure analyses show there exists strong Ni-Re electronic interaction and it is mainly contributed by the d-d *** characteristic features of the electronic states of the Re doping effects are also *** is also found that Re atoms prefer the Al sites inγside at the *** density of states at or near the Fermi level and the d-d hybridizations of NN Ni-Re are found to be important in the systems.

关键词： Re distribution first-principles calculations atom probe tomography Ni-based superalloys

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Critical assessment of mixing thermodynamic functions of Fe-Al binary melts based on atom-molecule coexistence theory

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Journal of Iron and Steel Research International 2020年第3期27卷 266-281页

作者： Xue-min Yang Jin-yan Li Fang-jia Yan Dong-ping Duan CAS Key Laboratory of Green Process and Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China Department of Metallurgy and Raw Materials China Metallurgical Industry Planning and Research InstituteBeijing 100711China

In order to further verify the accuracy and feasibility of the calculated mass action concentrations Ni of Al and Fe by the developed atom and molecule coexistence theory(AMCT)model,i.e.,AMCT-N,model,for representing activities aR,i of Al and Fe in Fe-Al binary melts reported in the first part of the serial studies,the molar mixing thermodynamic functions of Fe-Al binary melts over a temperature range from 1823 to 1973 K have been calculated based on Ni of Al and Fe as well as the effect of temperature on activity coefficients 7,of Al and Fe as■lnγj/■T=■ln(Ni/xi)/dT by the developed AMCTN-Ni model,where T is absolute temperature and.v,is the mole fraction of element i or compound i in metallic *** reported molar mixing thermodynamic functions of Fe-Al binary melts as well as the reported excess molar mixing thermodynamic functions of Fe-Al binary melts relative to ideal solution as a basis from the available literatures have been critically assessed and applied as criteria to verify the developed AMCT-Al,*** effect of changing temperature onγi of Al and Fe,i.e.,activity coefficient gradients■lnγAl/■T and■lnγFe/■T,which are two indispensable parameters to calculate the molar mixing thermodynamic functions of Fe-Al binary melts,can be accurately obtained by the developed AMCT-Ni,model and expressed by the cubic polynomial *** only the partial molar mixing thermodynamic functions of Al and Fe in Fe-Al binary melts but also the integral molar mixing thermodynamic functions of Fe-Al binary melts can be accurately calculated by the developed AMCT-Al,***,the excess partial and integral molar mixing thermodynamic functions of Fe-Al binary melts relative to ideal solution as a basis can also be precisely calculated by the developed AMCT-Ni,model.

关键词： Thermodynamic assessment Fe-Al binary melt Molar mixing thermodynamic function Excess molar mixing thermodynamic function Activity atom and molecule coexistence theory

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Crystallization and impact history of a meteoritic sample of early lunar crust(NWA 3163)refined by atom probe geochronology

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Geoscience Frontiers 2019年第5期10卷 1841-1848页

作者： L.F. White D.E. Moser K.T. Tait B. Langelier I. Barker J.R. Darling Centre for Applied Planetary Mineralogy Department of Natural HistoryRoyal Ontario MuseumTorontoOntarioM5S 2C6Canada Department of Earth Sciences University of TorontoTorontoOntarioM5S 3B1Canada Department of Earth Sciences University of Western OntarioLondonN6A 5B7Canada Canadian Centre for Electron Microscopy McMaster UniversityHamiltonOntarioCanada School of Earth and Environmental Science University of PortsmouthPortsmouthUK

Granulitic lunar meteorites offer rare insights into the timing and nature of igneous,metamorphic and impact processes in the lunar *** dating the different events recorded by these materials is very challenging,however,due to low trace element abundances (***,Nd,Lu,Hf),rare micrometerscale U-Th-bearing accessory minerals,and disturbed Ar-Ar systematics following a multi-stage history of shock and thermal *** we report on micro-baddeleyite grains in granulitic mafic breccia NWA 3163 for the first time and show that targeted microstructural analysis (electron backscatter diffraction) and nanoscale geochronology (atom probe tomography) can overcome these barriers to lunar chronology.A twinned (-90°/) baddeleyite domain yields a 232Th/208Pb age of 4328 ± 309 Ma,which overlaps with a robust secondary ion mass spectrometry (SIMS) 207Pb/206Pb age of 4308± 18.6 Ma and is interpreted here as the crystallization age for the igneous protolith of NWA 3163.A second microstructural domain,< 2 mm in width,contains patchy overprinting baddeleyite and yields a Th-Pb age of 2175± 143 Ma,interpreted as dating the last substantial impact event to affect the *** finding demonstrates the potential of combining microstructural characterization with nanoscale geochronology when resolving complex P-T-t histories in planetary materials,here yielding the oldest measured crystallization age for components of lunar granulite NWA 3163 and placing further constraints on the formation and evolution of lunar crust.

关键词： Baddeleyite U-Th-Pb isotopes EBSD atom probe tomography Geochronology Northwest Africa 3163

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