Chiral Symmetry and Electron-Electron Interaction in Many-Body Gap Formation in Graphene

We study a many-body ground state of graphene in perpendicular magnetic fields. Chiral symmetry in graphene enables us to determine the many-body ground state, which turns out to be a doubly degenerate chiral condensate for the half-filled (undoped) case. In the ground state a prominent charge accumulation emerges along zigzag edges. We also show that gapless excitations are absent despite the presence of the robust edge modes, which is consistent with the Chern number C = 0.Comment: 4 pages, 3 figures, proceeding of 26th International Conference on Low Temperature Physics (LT26

Interplay between isoscalar and isovector correlations in neutron-rich nuclei

The interplay between isoscalar and isovector correlations in the 1$^{-}$ states in neutron-rich (N$\neq$Z) even-even nuclei is studied, taking examples of the nuclei, $^{22}_{8}$O$_{14}$ and $^{24}_{8}$O$_{16}$. The excitation modes explored are isovector dipole and isoscalar compression dipole modes. The self-consistent Hartree-Fock plus the random-phase approximation with the Skyrme interaction, SLy4, is solved in coordinate space so as to take properly into account the continuum effect. The isovector peak induced by isoscalar correlation, the isoscalar peak induced by isovector correlation, and the possible collective states made by both isoscalar and isovector correlations, ("iS-iV pigmy resonance"), are shown. The strong neutron-proton interaction in nuclei can be responsible for controlling the isospin structure of normal modes. It is explicitly shown that in the scattering by isoscalar (isovector) particles on N$\neq$Z even-even nuclei isovector (isoscalar) strength in addition to isoscalar (isovector) strength may be populated.Comment: 20 pages,7 figure

A microscopic investigation of the transition form factor in the region of collective multipole excitations of stable and unstable nuclei

We have used a self-consistent Skyrme-Hartree-Fock plus Continuum-RPA model to study the low-multipole response of stable and neutron/proton-rich Ni and Sn isotopes. We focus on the momentum-transfer dependence of the strength distribution, as it provides information on the structure of excited nuclear states and in particular on the variations of the transition form factor (TFF) with the energy. Our results show, among other things, that the TFF may show significant energy dependence in the region of the isoscalar giant monopole resonance and that the TFF corresponding to the threshold strength in the case of neutron-rich nuclei is different compared to the one corresponding to the respective giant resonance. Perspectives are given for more detailed future investigations.Comment: 13 pages, incl. 9 figures; to appear in J.Phys.G, http://www.iop.org/EJ/jphys

Kerr-Schild Structure and Harmonic 2-forms on (A)dS-Kerr-NUT Metrics

We demonstrate that the general (A)dS-Kerr-NUT solutions in D dimensions with ([D/2], [(D+1)/2]) signature admit [D/2] linearly-independent, mutually-orthogonal and affinely-parameterised null geodesic congruences. This enables us to write the metrics in a multi-Kerr-Schild form, where the mass and all of the NUT parameters enter the metrics linearly. In the case of D=2n, we also obtain n harmonic 2-forms, which can be viewed as charged (A)dS-Kerr-NUT solution at the linear level of small-charge expansion, for the higher-dimensional Einstein-Maxwell theories. In the BPS limit, these 2-forms reduce to n-1 linearly-independent ones, whilst the resulting Calabi-Yau metric acquires a Kahler 2-form, leaving the total number the same.Comment: Latex, 11 pages, references adde

Isoscalar dipole strength in ^{208}_{82}Pb_{126}: the spurious mode and the strength in the continuum

Isoscalar dipole (compression) mode is studied first using schematic harmonic-oscillator model and, then, the self-consistent Hartree-Fock (HF) and random phase approximation (RPA) solved in coordinate space. Taking ^{208}Pb and the SkM* interaction as a numerical example, the spurious component and the strength in the continuum are carefully examined using the sum rules. It is pointed out that in the continuum calculation one has to use an extremely fine radial mesh in HF and RPA in order to separate, with good accuracy, the spurious component from intrinsic excitations.Comment: 19 pages, 2 figure

Integrated Management of Fruit fly and Its Impact on Yield of Crops with Effective Microorganisms (A Case Study)

Abstract Fruit Fly is a serious problem all over the world and research is carried out to develop methods for the insect pest. Most methods currently in use attract the male flies (McBride and Wood, 2000). However development of a technology using Effective Microorganisms indicated the possibilities of attracting female flies, which cause the most significant damage by laying eggs. This cost effective technique and results of this project are discussed. Introduction Melon Fly (Bacterocera cucubitae) was introduced to Hawaii from Japan in 1985. It has been recorded from more than 80 different host plants, including tomato, peppers, watermelons, cantaloupe, pumpkin, beans, eggplant, cucumber, squashes and passion fruit (Culliney, 2002). Eggs are inserted into fruit in bunches of 1 to 37 and hatches in 26 hours or more. Larvae feed in fruits; fruit develop water-soaked appearance and saprophytic organisms rot fruit. Adults feed on nectar, plant sap and juices from damage or decaying fruit. Adults have bright yellow stripes on the dorsum, and the secutellum is yellow. Wings have a dark brown stripe up the tip of the wing and other patterned areas on the wing (Marsden, 1979). Oriental fruit fly (Bacterocera dorsalis), a major fruit fly pest in Southeast Asia, was found on Oahu in 1946 and quickly spread throughout the islands. Over 90 plants have been recorded as hosts. In Hawaii, citrus, mango, papaya, guava, banana, and avocado are among the most important commercial crops attacked

RPA calculations with Gaussian expansion method

The Gaussian expansion method (GEM) is extensively applied to the calculations in the random-phase approximation (RPA). We adopt the mass-independent basis-set that has been tested in the mean-field calculations. By comparing the RPA results with those obtained by several other available methods for Ca isotopes, using a density-dependent contact interaction and the Woods-Saxon single-particle states, we confirm that energies, transition strengths and widths of their distribution are described by the GEM bases to good precision, for the $1^-$, $2^+$ and $3^-$ collective states. The GEM is then applied to the self-consistent RPA calculations with the finite-range Gogny D1S interaction. The spurious center-of-mass motion is well separated from the physical states in the $E1$ response, and the energy-weighted sum rules for the isoscalar transitions are fulfilled reasonably well. Properties of low-energy transitions in $^{60}$Ca are argued in some detail.Comment: 30 pages including 12 figure