1,040 research outputs found

    Nonpropagation of massive mode on AdS2 in topologically massive gravity

    Full text link
    Making use of Achucarro-Ortiz (AO) type of dimensional reduction, we study the topologically massive gravity with a negative cosmological constant on AdS2 spacetimes. For a constant dilaton, this two-dimensional model also admits three AdS2 vacuum solutions, which are related to two AdS3 and warped AdS3 backgrounds with an identification upon uplifting three dimensions. We carry out the perturbation analysis around these backgrounds to find what is a physically propagating field. However, it turns out that there is no propagating massive mode on AdS2 background, in contrast to the Kaluza-Klein (KK) type of dimensional reduction. We note that two dimensionally reduced actions are different and thus, the non-equivalence of their on-shell amplitudes is obtained.Comment: 19 pages, version to appear in EPJ

    Temperature-dependent Raman spectroscopy in BaRuO3_3 systems

    Full text link
    We investigated the temperature-dependence of the Raman spectra of a nine-layer BaRuO3_3 single crystal and a four-layer BaRuO3_3 epitaxial film, which show pseudogap formations in their metallic states. From the polarized and depolarized spectra, the observed phonon modes are assigned properly according to the predictions of group theory analysis. In both compounds, with decreasing temperature, while A1gA_{1g} modes show a strong hardening, EgE_g (or E2gE_{2g}) modes experience a softening or no significant shift. Their different temperature-dependent behaviors could be related to a direct Ru metal-bonding through the face-sharing of RuO6_6. It is also observed that another E2gE_{2g} mode of the oxygen participating in the face-sharing becomes split at low temperatures in the four layer BaRuO3_3 . And, the temperature-dependence of the Raman continua between 250 \sim 600 cm1^{-1} is strongly correlated to the square of the plasma frequency. Our observations imply that there should be a structural instability in the face-shared structure, which could be closely related to the pseudogap formation of BaRuO3_3 systems.Comment: 8 pages, 6 figures. to be published in Phys. Rev.

    Registration of 'Jeokwangtangkong' Peanut

    Get PDF
    'Jeokwangtangkong' peanut (Arachis hypogaea L. subsp.fastigiata var. vulgaris) (Reg. no. CV-63, PI607913 is a spanish-type developed at the International Crops Research Insitute for the Semi-Arid Tropics (ICRISAT), Patancheru, Andhra Pradesh, India It was introduced into the Republic Of Korea in 1989 as ICGV 86326. After five years of evaluaton, it was released in 1996 as Jeokwangtangkong for cultivation in Korea

    Z^* Resonances: Phenomenology and Models

    Get PDF
    We explore the phenomenology of, and models for, the Z^* resonances, the lowest of which is now well established, and called the Theta. We provide an overview of three models which have been proposed to explain its existence and/or its small width, and point out other relevant predictions, and potential problems, for each. The relation to what is known about KN scattering, including possible resonance signals in other channels, is also discussed.Comment: 29 pages, uses RevTeX4; expanded version (published form

    Spin-dependent (magneto)transport through a ring due to spin-orbit interaction

    Full text link
    Electron transport through a one-dimensional ring connected with two external leads, in the presence of spin-orbit interaction (SOI) of strength \alpha and a perpendicular magnetic field is studied. Applying Griffith's boundary conditions we derive analytic expressions for the reflection and transmission coefficients of the corresponding one-electron scattering problem. We generalize earlier conductance results by Nitta et al. [Appl. Phys. Lett. 75, 695 (1999)] and investigate the influence of \alpha, temperature, and a weak magnetic field on the conductance. Varying \alpha and temperature changes the position of the minima and maxima of the magnetic-field dependent conductance, and it may even convert a maximum into a minimum and vice versa.Comment: 19 pages, 9 figure

    Hawking Temperature in Taub-NUT (A)dS spaces via the Generalized Uncertainty Principle

    Full text link
    Using the extended forms of the Heisenberg uncertainty principle from string theory and the quantum gravity theory, we drived Hawking temperature of a Taub-Nut-(A)dS black hole. In spite of their distinctive natures such as asymptotically locally flat and breakdown of the area theorem of the horizon for the black holes, we show that the corrections to Hawking temperature by the generalized versions of the the Heisenberg uncertainty principle increases like the Schwarzschild-(A)dS black hole and give the reason why the Taub-Nut-(A)dS metric may have AdS/CFT dual picture.Comment: version published in General Relativity and Gravitatio

    Two charged strangeonium-like structures observable in the Y(2175)ϕ(1020)π+πY(2175) \to \phi(1020)\pi^{+} \pi^{-} process

    Full text link
    Via the Initial Single Pion Emission (ISPE) mechanism, we study the ϕ(1020)π+\phi(1020)\pi^{+} invariant mass spectrum distribution of Y(2175)ϕ(1020)π+πY(2175) \to \phi(1020)\pi^{+} \pi^{-}. Our calculation indicates there exist a sharp peak structure (Zs1+Z_{s1}^+) close to the KKˉK\bar{K}^\ast threshold and a broad structure (Zs2+Z_{s2}^+) near the KKˉK^\ast\bar{K}^\ast threshold. In addition, we also investigate the ϕ(1680)ϕ(1020)π+π\phi(1680) \to \phi(1020)\pi^{+} \pi^{-} process due to the ISPE mechanism, where a sharp peak around the KKˉK\bar{K}^\ast threshold appears in the ϕ(1020)π+\phi(1020)\pi^{+} invariant mass spectrum distribution. We suggest to carry out the search for these charged strangeonium-like structures in future experiment, especially Belle II, Super-B and BESIII.Comment: 7 pages, 5 figures. Accepted by Eur. Phys. J.

    Long-distant contribution and χc1\chi_{c1} radiative decays to light vector meson

    Full text link
    The discrepancy between the PQCD calculation and the CLEO data for χc1γV\chi_{c1}\to \gamma V (V=ρ0,ω,ϕV=\rho^0,\,\omega,\,\phi) stimulates our interest in exploring extra mechanism of χc1\chi_{c1} decay. In this work, we apply an important non-perturbative QCD effect, i.e., hadronic loop mechanism, to study χc1γV\chi_{c1}\to \gamma V radiative decay. Our numerical result shows that the theoretical results including the hadronic loop contribution and the PQCD calculation of χc1γV\chi_{c1}\to \gamma V are consistent with the corresponding CLEO data of χc1γV\chi_{c1}\to \gamma V. We expect further experimental measurement of χc1γV\chi_{c1}\to \gamma V at BES-III, which will be helpful to test the hadronic loop effect on χc1\chi_{c1} decay.Comment: 7 pages, 2 figures. Accepted for publication in Eur. Phys. J.

    Layered ferromagnet-superconductor structures: the π\pi state and proximity effects

    Full text link
    We investigate clean mutilayered structures of the SFS and SFSFS type, (where the S layer is intrinsically superconducting and the F layer is ferromagnetic) through numerical solution of the self-consistent Bogoliubov-de Gennes equations for these systems. We obtain results for the pair amplitude, the local density of states, and the local magnetic moment. We find that as a function of the thickness dFd_F of the magnetic layers separating adjacent superconductors, the ground state energy varies periodically between two stable states. The first state is an ordinary "0-state", in which the order parameter has a phase difference of zero between consecutive S layers, and the second is a "π\pi-state", where the sign alternates, corresponding to a phase difference of π\pi between adjacent S layers. This behavior can be understood from simple arguments. The density of states and the local magnetic moment reflect also this periodicity.Comment: 12 pages, 10 Figure

    Light-Front Approach for Pentaquark Strong Decays

    Full text link
    Assuming the two diquark structure for the pentaquark state as advocated in the Jaffe-Wilczek model, we study the strong decays of light and heavy parity-even pentaquark states using the light-front quark model in conjunction with the spectator approximation. The narrowness of the Theta width is ascribed to the p-wave configuration of the diquark pair. Taking the Theta width as a benchmark, we estimate the rates of the strong decays Xi_{3/2}-- to Xi- pi-, Sigma- K-, Sigma_{5c}0 to D_s- p, D_{s0}*- p and Xi_{5c}0 to D_s- Sigma+, D_{s0}^{*-} Sigma+ with Sigma_{5c} Xi_{5c} being antisextet charmed pentaquarks and D_{s0}* a scalar strange charmed meson. The ratio of Gamma(P_c to Baryon D_{s0}*)/Gamma(P_c to Baryon D_s) is very useful for verifying the parity of the antisextet charmed pentaquark P_c. It is expected to be of order unity for an even parity P_c and much less than one for an odd parity pentaquark.Comment: 24 pages, 2 figure
    corecore