5,775 research outputs found

    Attainable entanglement of unitary transformed thermal states in liquid-state nuclear magnetic resonance with the chemical shift

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    Recently, Yu, Brown, and Chuang [Phys. Rev. A {\bf 71}, 032341 (2005)] investigated the entanglement attainable from unitary transformed thermal states in liquid-state nuclear magnetic resonance (NMR). Their research gave an insight into the role of the entanglement in a liquid-state NMR quantum computer. Moreover, they attempted to reveal the role of mixed-state entanglement in quantum computing. However, they assumed that the Zeeman energy of each nuclear spin which corresponds to a qubit takes a common value for all; there is no chemical shift. In this paper, we research a model with the chemical shifts and analytically derive the physical parameter region where unitary transformed thermal states are entangled, by the positive partial transposition (PPT) criterion with respect to any bipartition. We examine the effect of the chemical shifts on the boundary between the separability and the nonseparability, and find it is negligible.Comment: 9 pages, 1 figures. There were mistakes in the previous version. The main results don't change, but our motivation has to be reconsidere

    Large gauge invariant non-standard neutrino interactions

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    Theories beyond the Standard Model must necessarily respect its gauge symmetry. This implies strict constraints on the possible models of non-standard neutrino interactions, which we analyze. The focus is set on the effective low-energy dimension six and eight operators involving four leptons, decomposing them according to all possible tree-level mediators, as a guide for model building. The new couplings are required to have sizeable strength, while processes involving four charged leptons are required to be suppressed. For non-standard interactions in matter, only diagonal tau-neutrino interactions can escape these requirements and can be allowed to result from dimension six operators. Large non-standard neutrino interactions from dimension eight operators alone are phenomenologically allowed in all flavour channels and shown to require at least two new mediator particles. The new couplings must obey general cancellation conditions both at the dimension six and eight levels, which result from expressing the operators obtained from the mediator analysis in terms of a complete basis of operators. We illustrate with one example how to apply this information to model building.Comment: 34 pages, 4 figures, 5 tables. Final version in PR

    The Chandra view of the Largest Quasar Lens SDSS J1029+2623

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    We present results from Chandra observations of the cluster lens SDSS J1029+2623 at z_l=0.58, which is a gravitationally lensed quasar with the largest known image separation. We clearly detect X-ray emission both from the lensing cluster and the three lensed quasar images. The cluster has an X-ray temperature of kT = 8.1 (+2.0, -1.2) keV and bolometric luminosity of L_X = 9.6e44 erg s^-1. Its surface brightness is centered near one of the brightest cluster galaxies, and it is elongated East-West. We identify a subpeak North-West of the main peak, which is suggestive of an ongoing merger. Even so, the X-ray mass inferred from the hydrostatic equilibrium assumption appears to be consistent with the lensing mass from the Einstein radius of the system. We find significant absorption in the soft X-ray spectrum of the faintest quasar image, which can be caused by an intervening material at either the lens or source redshift. The X-ray flux ratios between the quasar images (after correcting for absorption) are in reasonable agreement with those at optical and radio wavelengths, and all the flux ratios are inconsistent with those predicted by simple mass models. This implies that microlensing effect is not significant for this system and dark matter substructure is mainly responsible for the anomalous flux ratios.Comment: 35 pages, 8 figures. Accepted for publication in Ap

    Rings of Dark Matter in Collisions Between Clusters of Galaxies

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    Several lines of evidence suggest that the galaxy cluster Cl0024+17, an apparently relaxed system, is actually a collision of two clusters, the interaction occurring along our line of sight. Recent lensing observations suggest the presence of a ring-like dark matter structure, which has been interpreted as the result of such a collision. In this paper we present NN-body simulations of cluster collisions along the line of sight to investigate the detectability of such features. We use realistic dark matter density profiles as determined from cosmological simulations. Our simulations show a "shoulder" in the dark matter distribution after the collision, but no ring feature even when the initial particle velocity distribution is highly tangentially anisotropic (σθ/σr>>1\sigma_\theta/\sigma_r >> 1). Only when the initial particle velocity distribution is circular do our simulations show such a feature. Even modestly anisotropic velocity distributions are inconsistent with the halo velocity distributions seen in cosmological simulations, and would require highly fine-tuned initial conditions. Our investigation leaves us without an explanation for the dark matter ring-like feature in Cl 0024+17 suggested by lensing observations.Comment: 7 pages (emulateapj), 9 figures. Expanded figures and text to match accepted versio

    L_X-T Relation and Related Properties of Galaxy Clusters

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    An observational approach is presented to constrain the global structure and evolution of the intracluster medium based on the ROSAT and ASCA distant cluster sample. From statistical analysis of the gas density profile and the connection to the LX-T relation under the beta-model, the scaled gas profile is nearly universal for the outer region and the LX(>0.2r500) is tightly related to the temperature through T^3 rather than T^2. On the other hand, a large density scatter exists in the core region and there is clearly a deviation from the self-similar scaling for clusters with a small core size. A direct link between the core size and the radiative cooling timescale suggest that t_cool is a parameter to control the gas structure and the appearance of small cores in regular clusters may be much connected with the thermal evolution. We derive the luminosity-ambient temperature (T') relation, assuming the universal temperature profile to find the dispersion around the relation significantly decreases: L_1keV is almost constant for a wide range of t_cool. We further examined the LX-Tbeta and LX-T'beta relations and showed a trend that merging clusters segregate from the regular clusters on the planes. A good correlation between t_cool and the X-ray morphology on the L_1keV-t_cool/t_age plane leads us to define three phases according to the different level of cooling, and draw a phenomenological picture: after a cluster collapses and t_cool falls below t_age, the core cools radiatively with quasi-hydrostatic balancing in the gravitational potential, and the central density gradually becomes higher to evolve from an outer-core-dominant cluster to inner-core-dominant cluster.Comment: 39 pages, 37 figures. Accepted for publication in ApJ. Version with high-quality color figures at http://cosmic.riken.jp/ota/publications/index.htm

    The published research paper: is it an important indicator of successful operational research at programme level?

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    Is a published research paper an important indicator of successful operational research at programme level in low-income countries? In academia, publishing in peer-reviewed scientific journals is highly encouraged and strongly pursued for academic recognition and career progression. In contrast, for those who engage in operational research at programme level, there is often no necessity or reward for publishing the results of research studies; it may even be criticized as being an unnecessary detraction from programme-related work. We present arguments to support publishing operational research from low-income countries; we highlight some of the main reasons for failure of publication at programme level and suggest ways forward

    GC–MS profile, anti-seizure and anti-pyretic activities of palm kernel nut oil and its isolate, N-Octanoic acid from specially breed palm kernel Elaeis guineensis

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    PURPOSE: Palm kernel nut oil (PKNO) from palm fruit of a rare breed of Elaeis guineensis (virescens), and one of the species belonging to the Elaeis genre of arecaceae family was subjected to Gas chromatography - Mass spectroscopic studies as well as anti-seizure and anti-pyretic studies. It is used in South-Eastern part of Nigeria as antipyretic and anti-seizure agents especially in children. The aim of this study was to evaluate the chemical contents of PKNO using GC-MS and to investigate the antiseizure and antipyretic properties of PKNO using animal model.METHOD: 1500 g Palm Kernels (PK) of the rare breed collected from Abia State were cracked open and the nuts (1000 g) poured into steel vessel and heated until oil was produced after charring the nuts. The oil (PKNO) was analyzed using GC-MS to determine its chemical composition. Yeast induced hyperthermia method was used for anti-pyretic studies while strychnine sulphate induced method was used for anti-seizure studies. PKNO and Octanoic acid (0.5 mg/kg ,1 mg/kg, 2 mg/kg) were administered intraperitoneally (IP).Paracetamol (0.15mg/kg) was used as reference standard for anti-pyretic assay while epilim and tegretol (0.14mg/kg, resp.) were used as reference standards for anti-seizure assay.RESULTS: The major component identified in the extract include: Dodecanoic  acid,2,3-dihydroxypropyl ester(19.36 %),n-Hexadecanoic acid(15.49  %),Dodecanoic acid( 12.51 %),Myristic acid ( 6.47 %), Dodecanedioic acid (3.93 %),n-Acetylpyrrolidone (3.67 %) , Thiazole (0.98 %) and Octanoic acid, OA ( 3.19 %).The anti-seizure results showed that doses of PKNO and OA used had Significant (p<0.02) anti-seizure activities by delaying the on-set of seizure from time of induction to time of first seizure observed. In yeast induced hyperthermia model, PKNO exhibited good level of anti-pyretic activities by direct reduction of pyrexia with the highest dose, 2.0 mg/kg. The PKNO and OA are proven to be safe till 3000 μl/kg as indicated by LD50 results.CONCLUSION: PKNO and its components mainly fatty acids, thiazole, and n- acetylpyrrolidone are potent and promising agents with anti-pyretic and antiseizure activities.Keywords: Anti-Seizure, anti-pyretic, Octanoic acid, elaeis virescens, GC-MS, Palm kernel nut oil (PKNO

    Lithium in garnet as a tracer of subduction zone metamorphic reactions: The record in ultrahigh-pressure metapelites at Lago di Cignana, Italy

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    Lithium is of great interest as a tracer of metamorphic reactions and related fluid-mineral interactions because of its potential to isotopically fractionate during inter- and intracrystalline diffusional processes. Study of its transfer through subduction zones, based on study of arc volcanic and metamorphic rocks, can yield insight regarding ocean-to-mantle chemical cycling. We investigated major- and trace-element concentrations and delta Li-7 in garnet in ultrahigh-pressure (UHP) Lago di Cignana metasedimentary rocks, relating these observations to reconstructed prograde devolatilization history. In all garnet crystals we studied, heavy rare earth elements (HREEs), Y, and Li showed strong zoning, with elevated concentrations in cores (15-50 ppm Li) and marked high-concentration anomalies (up to 117 ppm Li, 5500 ppm Y; little or no major-element shift) as growth annuli, in which some crystals showed subtle elevation in delta Li-7 greater than analytical error of similar to 3 parts per thousand (2 sigma). Rutile inclusions appeared abruptly at annuli and outward toward rims, accompanied by inclusions of a highly zoned, Ca- and rare earth element-rich phase and decreased Nb concentrations in garnet. These relationships are interpreted to reflect prograde garnet-forming reaction(s), in part involving titanite breakdown to stabilize rutile, which resulted in delivery of more abundant Y and HREEs at surfaces of growing garnet crystals to produce annuli. Co-enrichments in Li and Y + REEs are attributed to mutual incorporation via charge-coupled substitutions; thus, increased Li uptake was a passive consequence of elevated concentrations of Y + REEs. The small-scale fluctuations in delta Li-7 (overall range of similar to 9 parts per thousand) observed in some crystals may correlate with abrupt shifts in major-and trace-element concentrations, suggesting that changes in reactant phases exerted some control on the evolution of delta Li-7. For one garnet crystal, late-stage growth following partial resorption produced deviation in major- and trace-element compositions, including Li concentration, accompanied by a 10 parts per thousand-15 parts per thousand negative shift in delta Li-7, perhaps reflecting a change in the mechanism of incorporation or source of Li. These results highlight the value of measuring the major- and trace-element and isotope compositions of garnets in high-pressure and UHP metamorphic rocks in which matrix mineral assemblages are extensively overprinted by recrystallization during exhumation histories. Lithium concentrations and isotope compositions of the garnets can add valuable information regarding prograde (and retrograde) reaction history, kinetics of porphyroblast growth, intracrystalline diffusion, and fluid-rock interactions. This work, integrated with previous study of devolatilization in the Schistes Lustres/Cignana metasedimentary suite, indicates retention of a large fraction of the initially subducted sedimentary Li budget to depths approaching those beneath volcanic fronts, despite the redistribution of this Li among mineral phases during complex mineral reaction histories

    Energy levels of few electron quantum dots imaged and characterized by atomic force microscopy

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    Strong confinement of charges in few electron systems such as in atoms, molecules and quantum dots leads to a spectrum of discrete energy levels that are often shared by several degenerate quantum states. Since the electronic structure is key to understanding their chemical properties, methods that probe these energy levels in situ are important. We show how electrostatic force detection using atomic force microscopy reveals the electronic structure of individual and coupled self-assembled quantum dots. An electron addition spectrum in the Coulomb blockade regime, resulting from a change in cantilever resonance frequency and dissipation during tunneling events, shows one by one electron charging of a dot. The spectra show clear level degeneracies in isolated quantum dots, supported by the first observation of predicted temperature-dependent shifts of Coulomb blockade peaks. Further, by scanning the surface we observe that several quantum dots may reside on what topologically appears to be just one. These images of grouped weakly and strongly coupled dots allow us to estimate their relative coupling strengths.Comment: 11 pages, 6 figure
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