4,348 research outputs found

    On hydromagnetic flow due to a rotating disk with radiation effects

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    The effect of thermal radiation on the steady laminar convective hydromagnetic flow of a viscous and electrically conducting fluid due to a rotating disk of infinite extend is studied. The fluid is subjected to an external uniform magnetic field perpendicular to the plane of the disk. The governing Navier–Stokes and Maxwell equations of the hydromagnetic fluid, together with the energy equation, are transformed into nonlinear ordinary differential equations by using the von Karman similarity transformations. The resulting nonlinear ordinary differential equations are then solved numerically subject to the transformed boundary conditions by Runge–Kutta based shooting method. Comparisons with previously published works are performed and the results are found to be in excellent agreement. Numerical and graphical results for the velocity and temperature profiles as well as the skin friction and Nusselt number are presented and discussed for various parametric conditions

    Joint measurability, steering and entropic uncertainty

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    The notion of incompatibility of measurements in quantum theory is in stark contrast with the corresponding classical perspective, where all physical observables are jointly measurable. It is of interest to examine if the results of two or more measurements in the quantum scenario can be perceived from a classical point of view or they still exhibit non-classical features. Clearly, commuting observables can be measured jointly using projective measurements and their statistical outcomes can be discerned classically. However, such simple minded association of compatibility of measurements with commutativity turns out to be limited in an extended framework, where the usual notion of sharp projective valued measurements of self adjoint observables gets broadened to include unsharp measurements of generalized observables constituting positive operator valued measures (POVM). There is a surge of research activity recently towards gaining new physical insights on the emergence of classical behavior via joint measurability of unsharp observables. Here, we explore the entropic uncertainty relation for a pair of discrete observables (of Alice's system) when an entangled quantum memory of Bob is restricted to record outcomes of jointly measurable POVMs only. Within the joint measurability regime, the sum of entropies associated with Alice's measurement outcomes - conditioned by the results registered at Bob's end - are constrained to obey an entropic steering inequality. In this case, Bob's non-steerability reflects itself as his inability in predicting the outcomes of Alice's pair of non-commuting observables with better precision, even when they share an entangled state. As a further consequence, the quantum advantage envisaged for the construction of security proofs in key distribution is lost, when Bob's measurements are restricted to the joint measurability regime.Comment: 5 pages, RevTeX, 1 pdf figure, Comments welcom

    Effect of Calcium Nitrate and Potassium Nitrate Priming on Seed Germination and Seedling Vigour of Papaya (Carica papaya L.)

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    The effect of seed priming with calcium nitrate Ca (NO3)2 and potassium nitrate (KNO3) on germination and seedling vigour were studied in papaya varieties. Open pollinated local (gauty) papaya seeds were soaked in Ca (NO3)2 and KNO3 solutions (10000 ppm, 15000 ppm and 20000 ppm) up to 24 hours and germination percentage and seedling characteristics were recorded. The least number of days taken for seed germination (4.33 days), the highest germination percentage (82.56 % ), the highest shoot length (14.31 cm) the highest fresh biomass (1.36 g) and dry biomass (0.174 g) were recorded in 10000 ppm   Ca(NO3)2 treatment. Further, seeds of papaya varieties viz., Arka Surya, Arka Prabhat and Madhu bindhu were treated with 5000 ppm, 10000 ppm and 15000 ppm Ca (NO3)2 and observed that Arka Prabhat seeds treated with 10000 ppm Ca (NO3)2 hadtaken the least number of days for germination (4.75 days) and also the highest shoot length (25.2 cm). The results of the experiment proved the significant effect of calcium ions over potassium ions on papaya seed germination and seedling vigour

    Joint Measurability and Temporal Steering

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    Quintino et. al. (Phys. Rev. Lett. 113, 160402 (2014)) and Uola et. al. (Phys. Rev. Lett. 113, 160403 (2014)) have recently established an intrinsic relation between non-joint measurability and Einstein-Podolsky- Rosen steering. They showed that a set of measurements is incompatible (i.e., not jointly measurable) if and only if it can be used for the demonstration of steering. In this paper, we prove the temporal analog of this result viz., a set of measurements are incompatible if and only if it exhibits temporal steering.Comment: 6 pages,no figures, typos corrected, improved presentation; To appear in JOSA B feature issue "80 years of Steering and the Einstein-Podolsky-Rosen Paradox

    Granulometric Analysis of the Exotic Sandstones in and around Moreh and Chandel, Chandel District, Manipur

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    Chaotic assemblage of conglomerate, gritstone, sandstone, shale, limestone, chert and ophiolitic derivatives occurs along the western contact of Nagaland-Manipur ophiolite belt in N-S to NNE-SSW trending direction. This assemblage is known as sedimentary melange and extends for about 200 km from north-east of Chokla in Nagaland to the south of Moreh in Manipur. Sandstones being the dominant litho-unit among the sedimentary mélange have been selected for the present study. These sandstones occur as floating bodies intermingling with both Disangs and ophiolite, hence the term exotic sandstone is used. Analysis of grain size data of these exotic sandstones in and around Moreh and Chandel, Chandel district reveals that all the samples show unimodal distribution. Cumulative curves suggest saltation and suspension are the major mode of transportation of these sediments. Mean values ranging from 1.40 ? to 3.29 ? suggest medium to very fine sand size. Standard deviation values (0.20 to 1.10) suggest that these sediments are very well sorted to moderately sorted and indicate fluctuating energy conditions during the time of deposition. The values of skewness range from -0.88 to 0.19 and 76.31% of the samples are negatively skewed, indicating high energy condition during the time of deposition of the sediments. Bivariate plots suggest that sediments were deposited both in fluvial and near shore environments. Discriminant function analysis reveals that exotic sandstones of the present study area were deposited under diverse condition

    Local Invariants and Pairwise Entanglement in Symmetric Multi-qubit System

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    Pairwise entanglement properties of a symmetric multi-qubit system are analyzed through a complete set of two-qubit local invariants. Collective features of entanglement, such as spin squeezing, are expressed in terms of invariants and a classifcation scheme for pairwise entanglement is proposed. The invariant criteria given here are shown to be related to the recently proposed (Phys. Rev. Lett. 95, 120502 (2005)) generalized spin squeezing inequalities for pairwise entanglement in symmetric multi-qubit states.Comment: 9 pages, 2 figures, REVTEX, Replaced with a published versio
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