8,434 research outputs found

    Two photon annihilation operators and squeezed vacuum

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    Inverses of the harmonic oscillator creation and annihilation operators by their actions on the number states are introduced. Three of the two photon annihilation operators, viz., a(sup +/-1)a, aa(sup +/-1), and a(sup 2), have normalizable right eigenstates with nonvanishing eigenvalues. The eigenvalue equation of these operators are discussed and their normalized eigenstates are obtained. The Fock state representation in each case separates into two sets of states, one involving only the even number states while the other involving only the odd number states. It is shown that the even set of eigenstates of the operator a(sup +/-1)a is the customary squeezed vacuum S(sigma) O greater than

    Two-Proton Radioactivity with 2p halo in light mass nuclei A==18−-34

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    Two-proton radioactivity with 2p halo is reported theoretically in light mass nuclei A == 18-34. We predict 19^{19}Mg, 22^{22}Si, 26^{26}S, 30^{30}Ar and 34^{34}Ca as promising candidates of ground state 2p-radioactivity with S2p_{2p} 0. Observation of extended tail of spatial charge density distribution, larger charge radius and study of proton single particle states, Fermi energy and the wave functions indicate 2p halo like structure which supports direct 2p emission. The Coulomb and centrifugal barriers in experimentally identified 2p unbound 22^{22}Si show a quasi-bound state that ensures enough life time for such experimental probes. Our predictions are in good accord with experimental and other theoretical data available so far.Comment: 5 Pages, 5 figure

    Localized structures in Kagome lattices

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    We investigate the existence and stability of gap vortices and multi-pole gap solitons in a Kagome lattice with a defocusing nonlinearity both in a discrete case and in a continuum one with periodic external modulation. In particular, predictions are made based on expansion around a simple and analytically tractable anti-continuum (zero coupling) limit. These predictions are then confirmed for a continuum model of an optically-induced Kagome lattice in a photorefractive crystal obtained by a continuous transformation of a honeycomb lattice

    Chaetotaxy of three nymphal instars of an ischnoceran louse, Aegypoecus perspicuus (Phthiraptera: Insecta)

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    The present study on three nymphal instars of Aegypoecus perspicuus indicated that these differ from each other not only an size, abdominal segmentation, chitinization but also in the number of setae occurring on head, thorax and abdomen. The study also supplements informations regarding the morphological features and chaetotaxy of three nymphal instars of A. perspicuus, occurring on Neophron percnopterus. The diagnostic features of three nymphal instars have also been discussed

    ROLE OF TERMINALIA ARJUNA IN ISCHEMIC HEART DISEASE (HRIDAROGA): A REVIEW

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    Now days, life is becoming very stressful and fast. As many diseases originate due to this hectic lifestyle. One of the important disease is Hridaroga (Ischemic heart disease), which is responsible for many deaths in early age. In Ayurveda, Hridaroga & their symptoms are described in many textbooks. Management of Hridaroga is also very critical and important. In modern medicine, only expensive interventional procedures are described but on the other hand, Ayurvedic herbs are better, cost effective & good therapeutic option for IHD (Hridaroga). The review emphasizes on various properties of Terminalia arjuna. Many clinical & animal studies on T.arjuna show its effect on ECG changes, LV functions & myocardial ischaemic reperfusion injury-etc. Besides this it also has antiatherosclerotic, anticoagulant, anti-infarction, hypolipidemic & hypotensive properties. So, Ayurvedic drug (T. arjuna) is a better option for the treatment of IHD (Hridaroga) because it can improve the quality of life in individuals & potentially save millions of lives

    Scaled free energies, power-law potentials, strain pseudospins and quasi-universality for first-order structural transitions

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    We consider ferroelastic first-order phase transitions with NOPN_{OP} order-parameter strains entering Landau free energies as invariant polynomials, that have NVN_V structural-variant Landau minima. The total free energy includes (seemingly innocuous) harmonic terms, in the n=6−NOPn = 6 -N_{OP} {\it non}-order-parameter strains. Four 3D transitions are considered, tetragonal/orthorhombic, cubic/tetragonal, cubic/trigonal and cubic/orthorhombic unit-cell distortions, with respectively, NOP=1,2,3N_{OP} = 1, 2, 3 and 2; and NV=2,3,4N_V = 2, 3, 4 and 6. Five 2D transitions are also considered, as simpler examples. Following Barsch and Krumhansl, we scale the free energy to absorb most material-dependent elastic coefficients into an overall prefactor, by scaling in an overall elastic energy density; a dimensionless temperature variable; and the spontaneous-strain magnitude at transition λ<<1\lambda <<1. To leading order in λ\lambda the scaled Landau minima become material-independent, in a kind of 'quasi-universality'. The scaled minima in NOPN_{OP}-dimensional order-parameter space, fall at the centre and at the NVN_V corners, of a transition-specific polyhedron inscribed in a sphere, whose radius is unity at transition. The `polyhedra' for the four 3D transitions are respectively, a line, a triangle, a tetrahedron, and a hexagon. We minimize the nn terms harmonic in the non-order-parameter strains, by substituting solutions of the 'no dislocation' St Venant compatibility constraints, and explicitly obtain powerlaw anisotropic, order-parameter interactions, for all transitions. In a reduced discrete-variable description, the competing minima of the Landau free energies induce unit-magnitude pseudospin vectors, with NV+1N_V +1 values, pointing to the polyhedra corners and the (zero-value) center.Comment: submitted to PR
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