Universal Quantum Computation in a Neutral Atom Decoherence Free Subspace

In this paper, we propose a way to achieve protected universal computation in a neutral atom quantum computer subject to collective dephasing. Our proposal relies on the existence of a Decoherence Free Subspace (DFS), resulting from symmetry properties of the errors. After briefly describing the physical system and the error model considered, we show how to encode information into the DFS and build a complete set of safe universal gates. Finally, we provide numerical simulations for the fidelity of the different gates in the presence of time-dependent phase errors and discuss their performance and practical feasibility.Comment: 7 pages, 8 figure

A DFT and KMC based study on the mechanism of the water gas shift reaction on the Pd(100) surface

We present a combined density functional theory (DFT) and Kinetic Monte Carlo (KMC) study of the water gas shift (WGS) reaction on the Pd(100) surface. We propose a mechanism comprising both the redox and the associative pathways for the WGS within a single framework, which consists of seven core elementary steps, which in turn involve splitting of a water molecule followed by the production of an H-atom and an OH-species on the Pd(100) surface. In the following steps, these intermediates then recombine with each other and with CO leading to the evolution of CO2, and H2. Seven other elementary steps, involving the diffusion and adsorption of the surface intermediate species are also considered for a complete description of the mechanism. The geometrical and electronic properties of each of the reactants, products, and the transition states of the core elementary steps are presented. We also discuss the analysis of Bader charges and spin densities for the reactants, transition states and the products of these elementary steps. Our study indicates that the WGS reaction progresses simultaneously via the direct oxidation and the carboxyl paths on the Pd(100) surface

Study on weed flora and their influence on patchouli (Pogostemon cablin Benth.) oil and patchoulol

Experiments were conducted to study the weed flora and its influence on the yield of oil and Patchoulol by co-distillation of fresh Patchouli leaves with weed biomass at different proportions (0, 5, 10, 15 and 30%) during 2004-05 and 2005-06. The survey of weeds commonly growing in patchouli plantation was made and a total of 17 weed species were recorded. Alternanthera sessile, Cynodon dactylon and Oxalis cornicullata exhibited 100% frequency in both the years. A. sessile, C. dactylon and O. cornicullata had highest density during 1st year and the density of most of the weed species increased during 2nd year except C. dactylon and A. sessile. Co-distillation of fresh Patchouli leaves with weeds at the rate of 0, 5, 10,15 and 30% yielded 0.70, 0.67, 0.65, 0.50 and 0.43% oil, respectively. It was observed that the oil yield decreased gradually with the increase in weed biomass. However, the percentage of patchoulol showed a different behaviour. It decreased at 15% (53.7) and 30% (50.4) and increased at 5% (56.5) and 10% (63.8) treatments. The oil extracted with weed biomass imports a weedy odour, which may decrease its commercial value. © Academic Journals Inc

Oxidative addition reaction of rhodium(I) carbonyl complexes of the pyridine-aldehyde ligands and their catalytic activity in carbonylation reaction

Rhodium(I) carbonyl complexes [Rh(CO)2ClL] (1) where L = Py-2-CHO (a), Py-3-CHO (b) and Py-4-CHO (c) have been synthesized and characterized by elemental analyses, IR, 1H and 13C NMR spectroscopy. The complexes 1 undergo oxidative addition reactions with different types of electrophiles such as CH3I, C2H5I, C6H5CH2Cl and I2 to yield [Rh(CO)(COCH3)ClIL] (2), [Rh(CO)(COC2H5)ClIL] (3), [Rh(CO)(COCH2C6H5)Cl2L] (4) and [Rh(CO)ClI2L] (5) complexes, respectively. The kinetic study of the complexes1 with CH3I reveals a two-stage kinetics and the second-stage reactions are faster than that of the first stage by about 80–100 times. The rate of reaction of 1a is higherthanthatof1band1c.Thecatalyticactivityofcomplexes1incarbonylationofmethanol,ingeneral,ishigher(TON800–1250)than that of the well-known species [Rh(CO)2I2]− (TON 650)

Antifungal activity and chemical composition of Citrus reticulata Blanco essential oil against phytopathogens from North East India

The essential oil (EO) isolated by hydro-distillation from the peel of fully matured ripen fruits of Citrus reticulata Blanco were analyzed by GC and GC 13MS. Thirty seven different components were identified constituting approximatel

Catalytic activity of dicarbonylrhodium complexes of aminobenzoic acid ligands on carbonylation of alcohol

Rhodium(I) complexes of the type, [Rh(CO)2ClL] (1), where L = 2-aminobenzoic acid (a), 3-aminobenzoic acid (b) and 4-aminobenzoic acid (c), have been synthesised. Oxidative addition (OA) of complexes 1 with electrophiles like RI (R = CH3, C2H5) produce Rh(III) complexes of the type [Rh(CO)(COCH3)IClL] (2) and [Rh(CO)(COC2H5)IClL] (3). The OA reactions of complexes 1 with RI follow a two stage kinetics and the observed rate constants are in the order 1b > 1c > 1a irrespective of stages. The complexes 1 show higher catalytic activity for carbonylation of methanol and ethanol than that of the well known species [Rh(CO)2I2]"12

Restructuring of AuPd nanoparticles studied by a combined XAFS/DRIFTS approach

The use of AuPd nanoparticles in catalysis is widespread, with the activity being attributed to their precise structural properties. We demonstrate the restructuring of AuPd nanoparticles under CO oxidation conditions using a combined XAFS/DRIFTS approach. The fresh catalyst exhibits PdO islands at the surface of the nanoparticles, which are reduced under reaction conditions, a process observed via both DRIFTS and Pd K-edge XAFS measurements. From the EXAFS analysis alone the nanoparticles were observed to have a Au rich core with an outer region of intimately mixed Au and Pd atoms. This structure was found to remain mostly unaltered throughout reaction. However, the DRIFTS spectra showed that although Au was present on the surface during the initial stages of reaction the surface rearranged just before light-off, and contained only Pd atoms thereafter. This study highlights the advantage of this combined approach, where both the surface structure and local environment of the constituent metals can be probed simultaneously, allowing a complete picture of the restructuring of these bimetallic particles to be obtained under reaction condition

Cymbopogon citratus L. essential oil as a potential antifungal agent against key weed moulds of Pleurotus spp. spawn

The essential oil of Cymbopogon citratus L. (250–1500 p.p.m.) was tested in vitro for antifungal activity against seven Pleurotus spp. spawn-contaminating fungi, viz. Aspergillus flavus, A. fumigatus, A. niger, Alternaria alternata, Penicillium citrinum, Curvularia lunata and Trichoderma harzianum. Oil-enrichment resulted in significant (p < 0.05) reduction of growth for the pathogens examined. Fungal spore production inhibited up to 80% at 250 p.p.m. of the oil except for C. lunata, which was inhibited by only 30%. In the higher oil concentration (1500 p.p.m.) employed, fungal sporulation was completely retarded. Lemongrass oil reduces spore germination in A. flavus, A. fumigatus, A. alternata, P. citrinum and T. harzianum, with the effects dependent on oil concentration. However, lemongrass oil at 250 p.p.m. accelerated spore germination for A. niger and P. citrinum. Indeed, further increase in oil concentration shows complete inhibition. Among the pathogens, C. lunata was found to be most resistant strain, while A. niger was the most sensitive strain against lemongrass oil. Copyright © 2007 John Wiley & Sons, Ltd

Towards microfluidic reactors for in situ synchrotron infrared studies

Anodically bonded etched silicon microfluidic devices that allow infrared spectroscopic measurement of solutions are reported. These extend spatially well-resolved in situ infrared measurement to higher temperatures and pressures than previously reported, making them useful for effectively time-resolved measurement of realistic catalytic processes. A data processing technique necessary for the mitigation of interference fringes caused by multiple reflections of the probe beam is also describe

Carbonyl complexes of ruthenium(II) with unsymetrical phosphine- phosphinesulfide ligands of type Ph2P (CH2)nP(S)Ph2 n=1-4

Reaction of [Ru(CO) 2Cl 2] n with ligands Ph 2P(CH 2)nP(S)Ph 2 (n0/1(a), 2(b), 3(c), 4(d)) in 1:1 molar ratio produces complex cis[Ru(CO) 2Cl 2(PS/S)](1a)(PS/S0/h 2-(P, S) coordinated) and cis-[Ru(CO)2Cl2(P/S)](1b/d)(P/S0/h 1-(P) coordinated), while 1:2 molar ratio yields complex of the type cis-[Ru(CO) 2Cl 2(P/S) 2](2a/d). The complex 2a undergoes partial decarbonylation reaction inCH 2Cl 2/hexanesolutiontogiveanewchelatedcomplex[Ru(CO)Cl(PS/S) 2]Cl(2a?).AbstractionofhalidewithAgClO 4fromthe non-chelated complexes 1b/d and 2a/d afford corresponding chelated complexes [Ru(CO) 2Cl(PS/S)](ClO 4)(3b/d) and [Ru(CO) 2(PS/S) 2](ClO 4)2(4a/d). The molecular structure of the complex 2a? has been determined by single crystal X-ray diffraction. The ruthenium atom is at the centre of slightly distorted octahedral structure having the two phosphorus atoms of the twochelatedP,Scoordinatedligandsattrans toeachother,oneCOgroupandClatomcompletingthecoordinationsphere.Other complexes have been characterized by elemental analysis, IR, 1H and 31P {H} NMR spectroscopy