1,502 research outputs found

    Non-Destructive Discrimination of arbitrary set of orthogonal quantum states by NMR using Quantum Phase Estimation

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    An algorithm based on quantum phase estimation, which discriminates quantum states nondestructively within a set of arbitrary orthogonal states, is described and experimentally verified by a NMR quantum information processor. The procedure is scalable and can be applied to any set of orthogonal states. Scalability is demonstrated through Matlab simulation

    Singlet state creation and Universal quantum computation in NMR using Genetic Algorithm

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    Experimental implementation of a quantum algorithm requires unitary operator decomposition. Here we treat the unitary operator decomposition as an optimization problem and use Genetic Algorithm, a global optimization method inspired by nature's evolutionary process for operator decomposition. As an application, we apply this to NMR Quantum Information Processing and find a probabilistic way of doing universal quantum computation using global hard pulses. We also demonstrate efficient creation of singlet state (as a special case of Bell state) directly from thermal equilibrium using an optimum sequence of pulses

    Assessment of variability in Asystasia gangetica (L.) T Anderson from the Western Ghats of Kerala, India

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    The variability shown by Asystasia gangetica (L.) T. Anderson has been thoroughly analyzed by considering gross and micromorphology. The species shows variability in flower color and leaf shape among the accessions collected from different geographical locations. However, the microspore sculpturing was found to be uniform and the seed surface architecture showed variation in one of the accessions as well as A. gangetica var. krishnae

    Anomalous Raman scattering from phonons and electrons of superconducting FeSe0.82_{0.82}

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    We report interesting anomalies in the temperature dependent Raman spectra of FeSe0.82_{0.82} measured from 3K to 300K in the spectral range from 60 to 1800 cm1^{-1} and determine their origin using complementary first-principles density functional calculations. A phonon mode near 100 cm1^{-1} exhibits a sharp increase by \sim 5% in frequency below a temperature Ts_s (\sim 100 K) attributed to strong spin-phonon coupling and onset of short-range antiferromagnetic order. In addition, two high frequency modes are observed at 1350 cm1^{-1} and 1600 cm1^{-1}, attributed to electronic Raman scattering from (x2y2x^2-y^2)to xzxz / yzyz dd-orbitals of Fe.Comment: 19 pages, 4 figures, 1 tabl

    Metallic monoclinic phase in VO2_2 induced by electrochemical gating: in-situ Raman study

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    We report in-situ Raman scattering studies of electrochemically top gated VO2_2 thin film to address metal-insulator transition (MIT) under gating. The room temperature monoclinic insulating phase goes to metallic state at a gate voltage of 2.6 V. However, the number of Raman modes do not change with electrolyte gating showing that the metallic phase is still monoclinic. The high frequency Raman mode Ag_g(7) near 616 cm1^{-1} ascribed to V-O vibration of bond length 2.06 \AA~ in VO6_6 octahedra hardens with increasing gate voltage and the Bg_g(3) mode near 654 cm1^{-1} softens. This shows that the distortion of the VO6_6 octahedra in the monoclinic phase decreases with gating. The time dependent Raman data at fixed gate voltages of 1 V (for 50 minute, showing enhancement of conductivity by a factor of 50) and 2 V (for 130 minute, showing further increase in conductivity by a factor of 5) show similar changes in high frequency Raman modes Ag_g(7) and Bg_g(3) as observed in gating. This slow change in conductance together with Raman frequency changes show that the governing mechanism for metalization is more likely to the diffusion controlled oxygen vacancy formation due to the applied electric field.Comment: 5 pages, 6 figure
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