Electrons in a cryogenic planar Penning trap and experimental challenges for quantum processing

We report on trapping of clouds of electrons in a cryogenic planar Penning trap at T ≤100 mK. We describe the experimental conditions to load, cool and detect electrons. Perspectives for the trapping of a single electron and for quantum information processing are given.     

The GPU‐enabled divide‐expand‐consolidate RI‐MP2 method (DEC‐RI‐MP2)

We report porting of the Divide‐Expand‐Consolidate Resolution of the Identity second‐order Møller–Plesset perturbation (DEC‐RI‐MP2) method to the graphic processing units (GPUs) using OpenACC compiler directives. It is shown that the OpenACC compiler directives implementation efficiently accelerates the rate‐determining step of the DEC‐RI‐MP2 method with minor implementation effort. Moreover, the GPU acceleration results in a better load balance and thus in an overall scaling improvement of the DEC algorithm. The resulting cross‐platform hybrid MPI/OpenMP/OpenACC implementation has scalable and portable performance on heterogeneous HPC architectures. The GPU‐enabled code was benchmarked using a reduced version of the S12L test set of Stefan Grimme (Grimme, Chem. Eur. J. 2012, 18, 9955) consisting of supramolecular complexes up to 158 atoms and 4292 contracted basis functions (cc‐pVTZ). The test set results demonstrate the general applicability of the DEC‐RI‐MP2 method showing results consistent with the DEC‐RI‐MP2 introductory paper (Baudin et al., J. Chem. Phys. 2016, 144, 054102) on molecules of complicated electronic structures. © 2016 Wiley Periodicals, Inc.     

微米级花状结构铜/聚乙烯吡咯烷酮的制备及其抗菌性能

采用液相还原的方法,以聚乙烯吡咯烷酮(PVP)为修饰剂,氯化铜为前驱体,水合肼为还原剂,成功制备了微米级Cu/PVP花状结构.采用扫描电子显微镜和X射线粉末衍射仪分析了所得样品的形貌与结构;利用差热分析测定了样品的热稳定性,并采用肉汤稀释法测试了其抗菌性能.结果表明,所制备的样品具有由多个Cu/PVP圆片组装而成的直径为6μm的花状结构,其形貌依赖于反应条件.与此同时,花状结构的Cu/PVP对金黄色葡萄球菌和大肠杆菌具有明显的抗菌作用,相应的最小抑菌浓度(MIC)和最小杀菌浓度(MBC)分别为:41.25mg/L、82.5mg/L,以及20.63mg/L、82.5mg/L.与单一Cu纳米微粒相比,花状结构的Cu/PVP复合物的抗菌持久性明显较好.     

分级微纳结构ZnO空心球的制备及其光电转换性能

以醋酸锌为锌源,二甘醇为溶剂,通过一种改进的溶剂热法制备出具有分级微纳结构的ZnO空心球。X射线衍射(XRD),扫描电子显微术(SEM),N₂吸附脱附等表征结果显示此ZnO材料的初级结构为纳米颗粒,次级结构为该纳米颗粒构筑的微米级多分散小球。聚焦离子束(FIB)切割实验表明,小球内部为中空结构。这种新颖的复合结构应用于染料敏化太阳电池(DSSC)领域,有两大优势：其初级结构提供了大的比表面以吸附更多染料分子,同时其次级结构和孔结构可以起到光散射中心的作用,提高光的利用率,从而最终提高了电池的光电转换效率。     

Compartmentalization within Nanofibers of Double-Decker Phthalocyanine Induces High-Performance Sensing in both Aqueous Solution and the Gas Phase

The functionalization of natural 1D architectures is dependent on hierarchically inner nanostructures. However, the artificial supramolecular nanofibers or nanotubes were rarely developed with complex inner structures. Inspired by a biomimetic strategy, single-molecule-diameter nanofibers of double-decker phthalocyanine (EuPc2) with compartmentalized internal space and fantastic electrochemical features were developed upon air/water interfacial assembly with poly-l -lysine. EuPc2/poly-l -lysine nanofibers can be electrochemical sensors both in water and the gas phase and have the best analytical performances for nitrite among all the porphyrins or phthalocyanines monomers and assemblies. Imbedding nitrite in compartments not only promotes the sensing but also changes the supramolecular chirality of nanofibers, and the morphological-dependent sensing properties of EuPc2 assemblies in water are different from that in the gas phase. These results suggest the unprecedented properties for diverse applications of artificial 1D architectures containing complex inner nanostructures.     

Deterministic generation of entangled photons by cavity-assisted interactions through adiabatic passage

We propose a deterministic scheme for generation of highly entangled photon states using a high-Q two-mode optical cavity and the dark state evolution. Because of the adiabatic operation, our proposal is robust to ambient noise, and the relevant dynamics is insensitive to the randomness of moderate fluctuations regarding experimental parameters. Our scheme not only works deterministically, but also has the advantage of achieving highly entangled photons by adiabatically increasing or decreasing the Rabi frequencies regarding the classical driving pulses, which would be practical in real implementation. Our scheme can also be extended to generation of multiphoton entanglement.     

Aryl azo imidazole assisted self-assembly of d metal complexes: Influence of halogen substitution and counter ions

A series of eight coordination networks has been obtained by the self-assembly of the aryl azo imidazole based building block and with d¹⁰ metal [Zn(II), Cd(II), and Hg(II)] and counter anion (Cl⁻, NO₃⁻, SCN⁻) in order to rationalize the effect of coordination behavior of the metal ion, the size of the anions and the substitution effects of ligands upon the structure adopted by these metal complexes. Influences of halogen (Cl⁻, Br⁻, and I⁻) substitutions are reflected in the precise molecular level architecture in the individual complexes. The parameters related to the coordination sphere depend on the metal-to-ligand ratios and are also influenced by the solvent of crystallization. A competition between the coordinating capabilities of the counter anion with ligands and its shape led to neutral and anionic metal complexes. Furthermore, various physicochemical studies viz. thermal behaviors, absorption spectra have been conducted to rationalize their structure in solution phase.     

Performance analysis of a 3D unstructured mesh hydrodynamics code on multi‐core and many‐core architectures

Several next generation high performance computing platforms are or will be based on the so‐called many‐core architectures, which represent a significant departure from commodity multi‐core architectures. A key issue in transitioning large‐scale simulation codes from multi‐core to many‐core systems is closing the serial performance gap, that is, overcoming the large difference in single‐core performance between multi‐core and many‐core systems. In this paper, we discuss how this problem was addressed for a 3D unstructured mesh hydrodynamics code, describe how Amdahl's law can be used to estimate performance targets and guide optimization efforts, and present timing studies performed on multi‐core and many‐core platforms. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.