Valence electronic structure of Mn in undoped and doped lanthanum manganites from relative K x-ray intensity studies

Relative $K$ x-ray intensities of $Mn$ in $Mn$, $MnO_{2}$, $LaMnO_{3}$ and $La_{0.7}B_{0.3}MnO_{3}$ ($B$ = $Ca$, $Sr$, and $Ce$) systems have been measured following excitation by 59.54 keV $\gamma$-rays from a 200 mCi $^{241}$Am point-source. The measured results for the compounds deviate significantly from the results of pure $Mn$. Comparison of the experimental data with the multiconfiguration Dirac-Fock (MCDF) effective atomic model calculations indicates reasonable agreement with the predictions of ionic model for the doped {manganites except} that the electron doped $La_{0.7}Ce_{0.3}MnO_{3}$ and hole doped $La_{0.7}Ca_{0.3}MnO_{3}$ compounds show some small deviations. The results of $MnO_{2}$ and $LaMnO_{3}$ deviate considerably from the predictions of the ionic model. Our measured $K\beta/K\alpha$ ratio of $Mn$ in $La_{0.7}Ca_{0.3}MnO_{3}$ cannot be explained as a linear superposition of $K\beta/K\alpha$ ratios of $Mn$ for the end members which is in contrast to the recent proposal by Tyson et al. from their $Mn$ $K\beta$ spectra.Comment: 14 pages, 4 figures. to appear in NIM-B.Please send an e-mail for figure

M-theory on AdS4×S7AdS_4\times S^7 at 1-loop and beyond

We study graviton scattering on $AdS_4\times S^7$, which is dual to the stress tensor multiplet four-point function in the maximally supersymmetric 3d $U(N)_1\times U(N)_{-1}$ ABJM theory. We compute 1-loop corrections to this holographic correlator coming from Witten diagrams with supergravity $R$ and higher derivative $R^4$ vertices, up to contact term ambiguities, and find that the flat space limit matches the corresponding terms in the 11d M-theory S-matrix. We then use supersymmetric localization to show that all the 1-loop contact terms vanish, as was previously observed for the $AdS_4\times S^7/\mathbb{Z}_2$ theory dual to $U(N)_2\times U(N)_{-2}$ ABJM. Finally, we use the recent localization results of Gaiotto and Abajian, as inspired by twisted M-theory, to compute all the short OPE coefficients in correlators of the stress tensor multiplet and the next lowest half-BPS operator, which we find saturate the bootstrap bounds on these mixed correlators for all $N$.Comment: 20 pages, 2 figures, sequel to arXiv:2107.1027

6d (2,0) and M-theory at 1-loop

We study the stress tensor multiplet four-point function in the 6d maximally supersymmetric $(2,0)$ $A_{N-1}$ and $D_N$ theories, which have no Lagrangian description, but in the large $N$ limit are holographically dual to weakly coupled M-theory on $AdS_7\times S^4$ and $AdS_7\times S^4/\mathbb{Z}_2$, respectively. We use the analytic bootstrap to compute the 1-loop correction to this holographic correlator coming from Witten diagrams with supergravity $R$ and the first higher derivative correction $R^4$ vertices, which is the first 1-loop correction computed for a non-Lagrangian theory. We then take the flat space limit and find precise agreement with the corresponding terms in the 11d M-theory S-matrix, some of which we compute for the first time using two-particle unitarity cuts.Comment: 35 pages plus appendices, v4 typos corrected, accepted to JHE

DARIS : a low-frequency distributed aperture array for radio astronomy in space

The frequency band below 30 MHz is one of the last unexplored bands in radio astronomy. This band is well suited for studying the early cosmos at high hydrogen redshifts, the so-called dark ages, extragalactic surveys, (extra) solar planetary bursts, and high energy particle physics. In addition, space research such as space weather tomography, are also areas of scientific interest. \ud \ud Due to ionospheric scintillation (below 30MHz) and its opaqueness (below 15MHz), earth-bound radio astronomy observations in these bands are either severely limited in sensitivity and spatial resolution or entirely impossible. A radio telescope in space obviously would not be hampered by the Earth's ionosphere. In the past, several (limited) studies have been conducted to explore possibilities for such an array in space. These studies considered aperture synthesis arrays in space, at the back-side of the Moon, or a satellite constellation operating in a coherent mode. \u

Field Localization and Enhancement of Phase Locked Second and Third Harmonic Generation in Absorbing Semiconductor Cavities

We predict and experimentally observe the enhancement by three orders of magnitude of phase mismatched second and third harmonic generation in a GaAs cavity at 650nm and 433nm, respectively, well above the absorption edge. Phase locking between the pump and the harmonics changes the effective dispersion of the medium and inhibits absorption. Despite hostile conditions the harmonics become localized inside the cavity leading to relatively large conversion efficiencies. Field localization plays a pivotal role and ushers in a new class of semiconductor-based devices in the visible and UV ranges

Ontology Based E-Healthcare Information Retrieval System: A Semantic Approach

With the increase of data in the health care system provides a base for the development of an effective information retrieval system. The implementation of such information retrieval system integrates the heterogeneous information from the healthcare environment. Most of the existing information retrieval systems are syntactic based systems, which will provide inefficient results for the search queries. The objective of this approach is to design a semantic based E-Healthcare information retrieval system. The proposed approach uses an ontology to define the disease-treatment information and will be used for the effective information retrieval. The designated approach is evaluated with a web based tool and the results shows that there is an improvement in the approach

Laser sources on a heterogeneous III-V/silicon platform

The heterogeneous integration of III-V semiconductor lasers on a silicon waveguide platform using DVS-BCB adhesive bonding is reviewed. Both mW-level lasers and ultra-compact laser sources are discussed

Earth Matter Effects at Very Long Baselines and the Neutrino Mass Hierarchy

We study matter effects which arise in the muon neutrino oscillation and survival probabilities relevant to atmospheric neutrino and very long baseline beam experiments. The inter-relations between the three probabilities P_{\mu e}, P_{\mu \tau} and P_{\mu \mu} are examined. It is shown that large and observable sensitivity to the neutrino mass hierarchy can be present in P_{\mu \mu} and P_{\mu \tau}. We emphasize that at baselines of > 7000 Km, matter effects in P_{\mu \tau} can be large under certain conditions. The muon survival rates in experiments with very long baselines thus depend on matter effects in both P_{\mu \tau} and P_{\mu e}. We indicate where these effects are sensitive to \theta_{13}, and identify ranges of E and L where the event rates increase with decreasing \theta_{13}, providing a handle to probe small \theta_{13}. The effect of parameter degeneracies in the three probabilities at these baselines and energies is studied in detail. Realistic event rate calculations are performed for a charge discriminating 100 kT iron calorimeter which demonstrate the possibility of realising the goal of determining the neutrino mass hierarchy using atmospheric neutrinos. It is shown that a careful selection of energy and baseline ranges is necessary in order to obtain a statistically significant signal, and that the effects are largest in bins where matter effects in both P_{\mu e} and P_{\mu \tau} combine constructively. Under these conditions, upto a 4\sigma signal for matter effects is possible (for \Delta_{31}>0) within a timescale appreciably shorter than the one anticipated for neutrino factories.Comment: 40 pages, 27 figures, version to match the published versio