4,440 research outputs found

    Schwinger-Keldysh Propagators from AdS/CFT Correspondence

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    We demonstrate how to compute real-time Green's functions for a class of finite temperature field theories from their AdS gravity duals. In particular, we reproduce the two-by-two Schwinger-Keldysh matrix propagator from a gravity calculation. Our methods should work also for computing higher point Lorentzian signature correlators. We elucidate the boundary condition subtleties which hampered previous efforts to build a Lorentzian-signature AdS/CFT correspondence. For two-point correlators, our construction is automatically equivalent to the previously formulated prescription for the retarded propagator.Comment: 16 pages, 1 figure, references added; to appear in JHE

    A new diagrammatic representation for correlation functions in the in-in formalism

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    In this paper we provide an alternative method to compute correlation functions in the in-in formalism, with a modified set of Feynman rules to compute loop corrections. The diagrammatic expansion is based on an iterative solution of the equation of motion for the quantum operators with only retarded propagators, which makes each diagram intrinsically local (whereas in the standard case locality is the result of several cancellations) and endowed with a straightforward physical interpretation. While the final result is strictly equivalent, as a bonus the formulation presented here also contains less graphs than other diagrammatic approaches to in-in correlation functions. Our method is particularly suitable for applications to cosmology.Comment: 14 pages, matches the published version. includes a modified version of axodraw.sty that works with the Revtex4 clas

    Effect of Organic Manures and Biofertilizers on Leaf and Fruit Nutrient Status in Guava (Psidium guajava L.) Cv. Sardar

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    Pooled analysis of two-year data on nutrient status of 'Sardar' guava raised under organic manures and biofertilizers indicated that maximum leaf nitrogen (1.73%), phosphorus (0.24%), potassium (1.23%), calcium (1.96%), magnesium (0.80%); and maximum fruit nitrogen (1.12%), phosphorus (0.15%), potassium (0.94%), calcium (0.22%), magnesium (0.66%) was recorded, respectively, after fruit harvest with application of full dose of nitrogen to the plant applied through poultry manure augmented with Azotobacter and Azospirillium

    Parallel algorithm with spectral convergence for nonlinear integro-differential equations

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    We discuss a numerical algorithm for solving nonlinear integro-differential equations, and illustrate our findings for the particular case of Volterra type equations. The algorithm combines a perturbation approach meant to render a linearized version of the problem and a spectral method where unknown functions are expanded in terms of Chebyshev polynomials (El-gendi's method). This approach is shown to be suitable for the calculation of two-point Green functions required in next to leading order studies of time-dependent quantum field theory.Comment: 15 pages, 9 figure

    Validation of Postnatal Care Health Data Reported Under Health Management Information System by the Primary Health Centers of Rural Vadodara, Gujarat

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    Postnatal care (PNC) is a part of maternal and child health (MCH) and important for the good health of both motherand child. Therefore, the present study was conducted with the aim to study the PNC data reported by primary health center/subcenter (PHC/SC) and validate them at the village level and assess quality of care given. Material and methods: A sampleof 20 PHCs, 13 rural and seven tribal, was selected using stratified random sampling. For every PHC, 2 SCs and for every SC,one village were selected. Data on PNC were collected from the PHC/SC records and validated by interviewing five beneficiariesfrom the village. Results: The district availability of PNC was 31.8%, while the overall accessibility was 52.2%. Adjustedutilization for the district was 74.7% for SBA and 14.7% for TBA. Effective coverage, adjusted for quality of care, for the districtwas 25.2%. Conclusions: The gap between the reported and validated data ranged from 15% to 51% of the reported

    Holographic Construction of Excited CFT States

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    We present a systematic construction of bulk solutions that are dual to CFT excited states. The bulk solution is constructed perturbatively in bulk fields. The linearised solution is universal and depends only on the conformal dimension of the primary operator that is associated with the state via the operator-state correspondence, while higher order terms depend on detailed properties of the operator, such as its OPE with itself and generally involve many bulk fields. We illustrate the discussion with the holographic construction of the universal part of the solution for states of two dimensional CFTs, either on RĂ—S1R \times S^1 or on R1,1R^{1,1}. We compute the 1-point function both in the CFT and in the bulk, finding exact agreement. We comment on the relation with other reconstruction approaches.Comment: 26 pages, 4 figures, v2: comments adde

    Renormalization of initial conditions and the trans-Planckian problem of inflation

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    Understanding how a field theory propagates the information contained in a given initial state is essential for quantifying the sensitivity of the cosmic microwave background to physics above the Hubble scale during inflation. Here we examine the renormalization of a scalar theory with nontrivial initial conditions in the simpler setting of flat space. The renormalization of the bulk theory proceeds exactly as for the standard vacuum state. However, the short distance features of the initial conditions can introduce new divergences which are confined to the surface on which the initial conditions are imposed. We show how the addition of boundary counterterms removes these divergences and induces a renormalization group flow in the space of initial conditions.Comment: 22 pages, 4 eps figures, uses RevTe
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