Emergence of a measurement basis in atom-photon scattering

The process of quantum measurement has been a long standing source of debate. A measurement is postulated to collapse a wavefunction onto one of the states of a predetermined set - the measurement basis. This basis origin is not specified within quantum mechanics. According to the theory of decohernce, a measurement basis is singled out by the nature of coupling of a quantum system to its environment. Here we show how a measurement basis emerges in the evolution of the electronic spin of a single trapped atomic ion due to spontaneous photon scattering. Using quantum process tomography we visualize the projection of all spin directions, onto this basis, as a photon is scattered. These basis spin states are found to be aligned with the scattered photon propagation direction. In accordance with decohernce theory, they are subjected to a minimal increase in entropy due to the photon scattering, while, orthogonal states become fully mixed and their entropy is maximally increased. Moreover, we show that detection of the scattered photon polarization measures the spin state of the ion, in the emerging basis, with high fidelity. Lastly, we show that while photon scattering entangles all superpositions of pointer states with the scattered photon polarization, the measurement-basis states themselves remain classically correlated with it. Our findings show that photon scattering by atomic spin superpositions fulfils all the requirements from a quantum measurement process

Formation, electrochemical and radical scavenging properties of novel ruthenium compounds with N, X-donor (X = O, N) heterocyclic chelators

Herein, we communicate the formation of novel ruthenium compounds with N, X-donor (X = O, N) heterocyclic- derived ligands. A paramagnetic ruthenium(IV) complex, [RuCl(pho)(bzca)(PPh3)](1) (pho = 2- aminophenolate; bzca = 2-carboxylate-1H-benzimidazole) was isolated from the reaction of the ruthenium(II) precursor, trans-[RuCl2(PPh3)3] and 2-((1H-benzimidazole)methylamino)phenol (Hbzap). The 1:1 molar reaction between the same metal precursor and N-(benzoxazole)-2-hydroxybenzamide (H2bhb) led to the formation of cis-Cl, trans-P-[RuIII(Hbhb)Cl2(PPh3)2](2). The dinuclear ruthenium compounds, (l-Htba,Cl)2[RuIICl(PPh3)]2(3) (Htba = N-(thiophene)methyl-benzoxazole-2-amine) and (l-Cl)2[RuIIICl(Hchpr)(PPh3)]2(4) (H2chpr = 2-amino-3-((tetrahydro-2H-pyran-4-ylimino)methyl)-4Hchromen- 4-one) were formed from the equimolar ratio coordination reactions between trans- [RuCl2(PPh3)3] and the respective free-ligands, Htba and H2chpr. These metal complexes were characterized via IR-, NMR- and UV–Vis spectroscopy, molar conductivity measurements and structural elucidations were confirmed by single crystal X-ray analysis. The X-ray studies revealed that all the metallic compounds exhibited octahedral geometries and that the Hbzap free ligand has undergone a unique molecular transformation to afford the pho and bzca bidentate chelators in 1. The electrochemical properties of the respective metal complexes were investigated by voltammetric analysis. The cyclic voltammograms (CVs) of 1–3 showed one redox couple while within the CV of the dinuclear compound 4, two redox couples were observed. The ligands and their metal complexes were also subjected to DPPH radical scavenging studies. The IC50 values showed that all the metallic compounds have higher radical scavenging activities than their corresponding free-ligands and the natural antioxidant, Vitamin C

Ruthenium complexes with lumazine derivatives: structural, electrochemical, computational and radical scavenging studies

In this research study, the formation and characterization of new ruthenium(II) and (III) complexes encompassing multidentate ligands derived from 6-acetyl-1,3, 7-trimethyllumazine (almz) are reported. The 1:1 molar coordination reactions of trans-[RuCl2(PPh3)3] with N-1-[1,3, 7-trimethyllumazine]benzohydride (bzlmz) and 6-(N-methyloxime)- 1,3,7-trimethyllumazine (ohlmz) formed a diamagnetic ruthenium(II) complex, cis-[RuCl2(bzlmz)(PPh3)] (1), and paramagnetic complex, cis-[RuIIICl2(olmz)(PPh3)] (2) [Holmz = 6-(N-hydroxy-N0-methylamino)-1,3,7-trimethyllumazine], respectively. These ruthenium complexes were characterized via physico-chemical and spectroscopic methods. Structural elucidations of the metal complexes were confirmed using single crystal X-ray analysis. The redox properties of the metal complexes were investigated via cyclic voltammetry. Electron spin resonance spectroscopy confirmed the presence of a paramagnetic metal centre in 2. The radical scavenging activities of the metal complexes were explored towards the DPPH and NO radicals. Quantum calculations at the density functional theory level provided insight into the interpretation of the IR and UV–Vis experimental spectra of 1

Coordination of di- and triimine ligands at ruthenium(II) and ruthenium(III) centers: structural, electrochemical and radical scavenging studies

Herein, we explore the coordination of di- and triimine chelators at ruthenium(II) and ruthenium(III) centers. The reactions of 2,6-bis-((4- tetrahydropyranimino)methyl)pyridine (thppy), N1,N2-bis((3-chromone) methylene)benzene-1,2-diamine (chb), and tris-((1H-pyrrol-2-ylmethylene) ethane)amine (H3pym) with trans-[RuIICl2(PPh3)3] afforded the diamagnetic ruthenium(II) complex cis-[RuCl2(thppy)(PPh3)] (1) and the paramagnetic complexes [mer-Ru2(μ-chb)Cl6(PPh3)2] (2), and [Ru(pym)] (3), respectively. The complexes were characterized by IR, NMR, and UV–vis spectroscopy and molar conductivity measurements. The structures were confirmed by single crystal X-ray diffraction studies. The redox properties of the metal complexes were probed via cyclic- and squarewave voltammetry. Finally, the radical scavenging capabilities of the metal complexes towards the NO and 2,2-di(4-tert-octylphenyl)-1-picrylhydrazyl (DPPH) radicals were investigate

Quantum control of 88^{88}Sr+^+ in a miniature linear Paul trap

We report on the construction and characterization of an apparatus for quantum information experiments using $^{88}$Sr$^+$ ions. A miniature linear radio-frequency (rf) Paul trap was designed and built. Trap frequencies above 1 MHz in all directions are obtained with 50 V on the trap end-caps and less than 1 W of rf power. We encode a quantum bit (qubit) in the two spin states of the $S_{1/2}$ electronic ground-state of the ion. We constructed all the necessary laser sources for laser cooling and full coherent manipulation of the ions' external and internal states. Oscillating magnetic fields are used for coherent spin rotations. High-fidelity readout as well as a coherence time of 2.5 ms are demonstrated. Following resolved sideband cooling the average axial vibrational quanta of a single trapped ion is $\bar n=0.05$ and a heating rate of $\dot{\bar n}=0.016$ ms$^{-1}$ is measured.Comment: 8 pages,9 figure

Clinical markers of Crohn\u27s disease severity and their association with opiate use

BACKGROUND: The safety of opiate use for patients with Crohn\u27s disease (CD) has long been a concern. The recent Crohn\u27s therapy, resource, evaluation, and assessment tool (TREAT) registry update has added to these concerns by demonstrating an association of opiate use with an increased risk of infection and death in CD. While the association is clear, the relationship of opiates to these negative outcomes is not. It is unknown whether opiates are a contributing factor to these negative outcomes or if their use is merely a marker of more severe disease. We hypothesized that opiate use is not harmful in CD but is a marker of disease severity and would be associated with commonly accepted clinical markers of severe CD such as early age at CD onset, disease duration, small intestinal involvement, a history of fistula or stricture, and lower quality of life (QOL) scores. METHODS: Data on CD history including pain medication usage were obtained from an interviewer directed survey of patients admitted to two tertiary care hospitals over a 2-year period. CD as the primary admitting diagnosis was not required. Active opiate use was defined by usage within the past month prior to admission. RESULTS: A total of 133 patients were approached to participate, of whom 108 consented to the survey, and 51 were active opiate users. Opiate using CD patients were more commonly smokers (22% vs. 3.45%, P \u3c 0.010), had fistulas (40% vs. 22.4%, P \u3c 0.048) and had a poorer quality of life score by short form inflammatory bowel disease questionnaire (mean 3.80 vs. 4.34, P \u3c 0.036) than non-opiate users. No difference was found between opiate users and non-users for age of diagnosis, disease duration, or a history of strictures. CONCLUSIONS: The study findings demonstrate that opiate use in CD is associated with markers of disease severity including fistulas, smoking, and lower QOL scores. The findings suggest that opiates may not be directly harmful to patients with CD, but may merely be another marker of disease severity. However, given opiates unproven benefits for long term CD pain control and risk of dependence, caution should still be exercised in their use

Flow cytometric S-phase fraction in soft-tissue sarcoma: prognostic importance analysed in 160 patients.

We could determine the S-phase fraction (SPF) by flow cytometric DNA analysis of paraffin archival material in 160 of 260 patients with soft-tissue sarcoma of extremity and trunk wall. The prognostic value of SPF was compared with other clinicopathological factors. The median follow-up time was 16 (6-31) years. In a univariate analysis, deep tumour location, increasing tumour size and histological malignancy grade, microscopic tumour necrosis, vascular invasion, DNA non-diploidy and high SPF (>3.0%) were associated with poor metastasis-free survival. In a multivariate analysis, microscopic tumour necrosis and high SPF were independently prognostic for metastasis. Used in combination with tumour size, microscopic tumour necrosis and vascular invasion, SPF could identify a group of patients with a 5-year metastasis-free survival rate of 0.97. This group constituted one-quarter of all patients. Patients with low SPF who did recur had a prolonged clinical course both as regards metastases and local recurrence. We conclude that SPF is a valuable adjunct in prognostication in soft-tissue sarcoma

Metformin and Myocardial Injury in Patients With Diabetes and ST-Segment Elevation Myocardial Infarction: A Propensity Score Matched Analysis

BACKGROUND: Although animal studies have documented metformin's cardioprotective effects, the impact in humans remains elusive. The study objective was to explore the association between metformin and myocardial infarct size in patients with diabetes presenting with ST‐segment elevation myocardial infarction. METHODS AND RESULTS: Data extraction used the National Cardiovascular Data CathPCI Registry in all patients with diabetes aged >18 years presenting with ST‐segment elevation myocardial infarction at 2 academic medical centers from January 2010 to December 2013. The exposure of interest was ongoing metformin use before the event. Propensity score matching was used for the metformin and nonmetformin groups on key prognostic variables. All matched pairs had acceptable D scores of <10%, confirming an efficient matching procedure. The primary outcome was myocardial infarct size, reflected by peak serum creatine kinase–myocardial band, troponin T, and hospital discharge left ventricular ejection fraction. Of all 1726 ST‐segment elevation myocardial infarction cases reviewed, 493 patients had diabetes (28.5%), with 208 metformin users (42.1%) and 285 nonusers. Matched pairs analysis yielded 137 cases per group. The difference between metformin and nonmetformin groups was −18.1 ng/mL (95% CI −55.0 to 18.8; P=0.56) for total peak serum creatine kinase–myocardial band and −1.1 ng/mL (95% CI −2.8 to 0.5; P=0.41) for troponin T. Median discharge left ventricular ejection fraction in both groups was 45, and the difference between metformin and nonmetformin users was 0.7% (95% CI −2.2 to 3.6; P=0.99). CONCLUSIONS: No statistically significant association of cardioprotection was found between metformin and myocardial infarct size in patients with diabetes and acute ST‐segment elevation myocardial infarction

High-fidelity state detection and tomography of a single ion Zeeman qubit

We demonstrate high-fidelity Zeeman qubit state detection in a single trapped 88 Sr+ ion. Qubit readout is performed by shelving one of the qubit states to a metastable level using a narrow linewidth diode laser at 674 nm followed by state-selective fluorescence detection. The average fidelity reached for the readout of the qubit state is 0.9989(1). We then measure the fidelity of state tomography, averaged over all possible single-qubit states, which is 0.9979(2). We also fully characterize the detection process using quantum process tomography. This readout fidelity is compatible with recent estimates of the detection error-threshold required for fault-tolerant computation, whereas high-fidelity state tomography opens the way for high-precision quantum process tomography