Violation of Leggett-Garg inequalities in quantum measurements with variable resolution and back-action

Quantum mechanics violates Leggett-Garg inequalities because the operator formalism predicts correlations between different spin components that would correspond to negative joint probabilities for the outcomes of joint measurements. However, the uncertainty principle ensures that such joint measurements cannot be implemented without errors. In a sequential measurement of the spin components, the resolution and back-action errors of the intermediate measurement can be described by random spin flips acting on an intrinsic joint probability. If the error rates are known, the intrinsic joint probability can be reconstructed from the noisy statistics of the actual measurement outcomes. In this paper, we use the spin-flip model of measurement errors to analyze experimental data on photon polarization obtained with an interferometric setup that allows us to vary the measurement strength and hence the balance between resolution and back-action errors. We confirm that the intrinsic joint probability obtained from the experimental data is independent of measurement strength and show that the same violation of the Leggett-Garg inequality can be obtained for any combination of measurement resolution and back-action.Comment: 17 pages, 7 figure

Characterisation and optimisation of a sample preparation method for the detection and quantification of atmospherically relevant carbonyl compounds in aqueous medium

Carbonyl compounds are ubiquitous in the atmosphere and either emitted primarily from anthropogenic and biogenic sources or they are produced secondarily from the oxidation of volatile organic compounds. Despite a number of studies about the quantification of carbonyl compounds a comprehensive description of optimised methods is scarce for the quantification of atmospherically relevant carbonyl compounds. The method optimisation was conducted for seven atmospherically relevant carbonyl compounds including acrolein, benzaldehyde, glyoxal, methyl glyoxal, methacrolein, methyl vinyl ketone and 2,3-butanedione. O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) was used as derivatisation reagent and the formed oximes were detected by gas chromatography/mass spectrometry (GC/MS). With the present method quantification can be carried out for each carbonyl compound originating from fog, cloud and rain or sampled from the gas- and particle phase in water. Detection limits between 0.01 and 0.17 μmol L−1 were found, depending on carbonyl compounds. Furthermore, best results were found for the derivatisation with a PFBHA concentration of 0.43 mg mL−1 for 24 h followed by a subsequent extraction with dichloromethane for 30 min at pH = 1. The optimised method was evaluated in the present study by the OH radical initiated oxidation of 3-methylbutanone in the aqueous phase. Methyl glyoxal and 2,3-butanedione were found to be oxidation products in the samples with a yield of 2% for methyl glyoxal and 14% for 2,3-butanedione after a reaction time of 5 h

Counterfactual control and quantum contextuality in multi-mode interferometers

As shown in previous work, quantum contextuality can be represented by interference effects in a three-path interferometer. A Hardy-like paradox is obtained when the absence of photons in two internal paths seems to contradict the presence of photons in a specific input port. Here, we consider the effects of counterfactual control on this scenario by analyzing the changes to the paths through the interferometer when the seemingly impossible input path is blocked. The effects on photons that never interact with the absorber in the blocked path reveals a characteristic signature of quantum contextuality that may help to explain why quantum interference is incompatible with measurement independent realities

Image Analysis of Intractable Epilepsy:18F-FDG PET Scan of the Cortical Dysplasia

開始ページ、終了ページ: 冊子体のページ付

Campholenic aldehyde ozonolysis: a mechanism leading to specific biogenic secondary organic aerosol constituents

In the present study, campholenic aldehyde ozonolysis was performed to investigate pathways leading to specific biogenic secondary organic aerosol (SOA) marker compounds. Campholenic aldehyde, a known α-pinene oxidation product, is suggested to be a key intermediate in the formation of terpenylic acid upon α-pinene ozonolysis. It was reacted with ozone in the presence and absence of an OH radical scavenger, leading to SOA formation with a yield of 0.75 and 0.8, respectively. The resulting oxidation products in the gas and particle phases were investigated employing a denuder/filter sampling combination. Gas-phase oxidation products bearing a carbonyl group, which were collected by the denuder, were derivatised by 2,4-dinitrophenylhydrazine (DNPH) followed by liquid chromatography/negative ion electrospray ionisation time-of-flight mass spectrometry analysis and were compared to the gas-phase compounds detected by online proton-transfer-reaction mass spectrometry. Particle-phase products were also analysed, directly or after DNPH derivatisation, to derive information about specific compounds leading to SOA formation. Among the detected compounds, the aldehydic precursor of terpenylic acid was identified and its presence was confirmed in ambient aerosol samples from the DNPH derivatisation, accurate mass data, and additional mass spectrometry (MS² and MS³ fragmentation studies). Furthermore, the present investigation sheds light on a reaction pathway leading to the formation of terpenylic acid, involving α-pinene, α-pinene oxide, campholenic aldehyde, and terpenylic aldehyde. Additionally, the formation of diaterpenylic acid acetate could be connected to campholenic aldehyde oxidation. The present study also provides insights into the source of other highly functionalised oxidation products (e.g. <i>m</i> / <i>z</i> 201, C₉H₁₄O₅ and <i>m</i> / <i>z</i> 215, C₁₀H₁₆O₅), which have been observed in ambient aerosol samples and smog chamber-generated monoterpene SOA. The <i>m</i> / <i>z</i> 201 and 215 compounds were tentatively identified as a C₉- and C₁₀-carbonyl-dicarboxylic acid, respectively, based on reaction mechanisms of campholenic aldehyde and ozone, as well as detailed interpretation of mass spectral data, in conjunction with the formation of corresponding DNPH derivatives

Contrasting P-T paths recorded in eclogitic garnet-clinopyroxene rocks from the Gondwana suture zone in southern India

第3回極域科学シンポジウム/第32回極域地学シンポジウム 11月30日（金） 国立極地研究所 ３階ラウン

Weak measurement of photon polarization by back-action induced path interference

The essential feature of weak measurements on quantum systems is the reduction of measurement back-action to negligible levels. To observe the non-classical features of weak measurements, it is therefore more important to avoid additional back-action errors than it is to avoid errors in the actual measurement outcome. In this paper, it is shown how an optical weak measurement of diagonal (PM) polarization can be realized by path interference between the horizontal (H) and vertical (V) polarization components of the input beam. The measurement strength can then be controlled by rotating the H and V polarizations towards each other. This well-controlled operation effectively generates the back-action without additional decoherence, while the visibility of the interference between the two beams only limits the measurement resolution. As the experimental results confirm, we can obtain extremely high weak values, even at rather low visibilities. Our method therefore provides a realization of weak measurements that is extremely robust against experimental imperfections.Comment: 11 pages, 3 figure

A new approach towards volumetric assessment of left ventricular function with MSCT

Cardiovascular CT is considered the diagnostic standard for establishing the presence of a functional and dynamic imaging system. It is difficult, however, to estimate the ventricular motion and volumes that are processed using hundreds and thousands of CT images, in a few moments

Parity Violation in Neutron Resonances in 107,109Ag

Parity nonconservation (PNC) was studied in p-wave resonances in Ag by measuring the helicity dependence of the neutron total cross section. Transmission measurements on natural Ag were performed in the energy range 32 to 422 eV with the time-of-flight method at the Manuel Lujan Neutron Scattering Center at Los Alamos National Laboratory. A total of 15 p-wave neutron resonances were studied in 107Ag and ninep-wave resonances in 109Ag. Statistically significant asymmetries were observed for eight resonances in 107Ag and for four resonances in109Ag. An analysis treating the PNC matrix elements as random variables yields a weak spreading width of Γw=(2.67-1.21+2.65)×10-7 eV for107Ag and Γw=(1.30-0.74+2.49)×10-7 eV for 109Ag

Terpenylic acid and related compounds: precursors for dimers in secondary organic aerosol from the ozonolysis of α- and β-pinene

In the present study, we have characterized the structure of a higher-molecular weight (MW) 358 α- and β-pinene dimeric secondary organic aerosol (SOA) product that received ample attention in previous molecular characterization studies and has been elusive. Based on mass spectrometric evidence for deprotonated molecules formed by electrospray ionization in the negative ion mode and chemical considerations, it is suggested that diaterpenylic acid is a key monomeric intermediate for dimers of the ester type. It is proposed that cis-pinic acid is esterified with the hydroxyl-containing diaterpenylic acid, which can be explained through acid-catalyzed hydrolysis of the recently elucidated lactone-containing terpenylic acid and/or diaterpenylic acid acetate, both first-generation oxidation products. To a minor extent, higher-MW 358 and 344 diester products are formed containing other terpenoic acids as monomeric units, i.e., diaterpenylic acid instead of cis-pinic acid, and diaterebic acid instead of diaterpenylic acid. It is shown that the MW 358 diester and related MW 344 compounds, which can be regarded as processed SOA products, also occur in ambient fine (PM2.5) rural aerosol collected at night during the warm period of the 2006 summer field campaign conducted at K-puszta, Hungary, a rural site with coniferous vegetation. This indicates that, under ambient conditions, the higher-MW diesters are formed in the particle phase over a longer time-scale than that required for gas-to-particle partitioning of their monomeric precursors in laboratory α-/β-pinene ozonolysis experiments