String creation in D6-brane background

The production of string charge during a crossing of certain oriented D-branes is studied. We compute the string charge in the system of a probe D2-brane and a background D6-brane by use of the equations of motion in the ten-dimensions. We confirm the creation of string charge as inflow from the background D6-brane.Comment: 11 pages, 1 figure, typos correcte

Gauge-Invariant Formulation of Adiabatic Self-Consistent Collective Coordinate Method

The adiabatic self-consistent collective coordinate (ASCC) method is a practical microscopic theory of large-amplitude collective motions in nuclei with superfluidity. We show that its basic equations are invariant against transformations involving the gauge angle in the particle-number space. By virtue of this invariance, a clean separation between the large-amplitude collective motion and the pairing rotational motion can be achieved, enabling us to restore the particle-number symmetry broken by the Hartree-Fock-Bogoliubov (HFB) approximation. We formulate the ASCC method explicitly in a gauge-invariant form. In solving the ASCC equations, it is necessary to fix the gauge. Applying this new formulation to the multi-O(4) model, we compare different gauge-fixing procedures and demonstrate that calculations using different gauges indeed yield the same results for gauge-invariant quantities, such as the collective path and quantum spectra. We suggest a gauge-fixing prescription that seems most convenient in realistic calculations.Comment: 27 pages, 7 figures, submitted to Prog. Theor. Phy

Effects of Time-Odd Components in Mean Field on Large Amplitude Collective Dynamics

We apply the adiabatic self-consistent collective coordinate (ASCC) method to the multi-O(4) model and study collective mass (inertia function) of the many-body tunneling motion. Comparing results with those of the exact diagonalization, we show that the ASCC method succeeds in describing gradual change of excitation spectra from an anharmonic vibration about the spherical shape to a doublet pattern associated with a deformed double-well potential possessing the oblate-prolate symmetry. The collective mass is significantly increased by the quadrupole-pairing contribution to time-odd components of the moving mean field. In contrast, the cranking (Inglis-Belyaev) mass based on the constrained mean field, which ignores the time-odd components, is smaller than the ASCC mass and fails to reproduce the exact spectra.Comment: 32 pages, 9 figure

Television-watching in the early years of life and the association with parents’ concerns about decreased visual acuity in their elementary school-aged child: results of a nationwide population-based longitudinal survey of Japan

Purpose To study the association between television-watching in the earlier years of life and subsequent parents’ concerns about decreased visual acuity in their elementary school-aged child. Study design Population-based longitudinal cohort. Methods Television-watching and its daily duration, as the main exposure, and parents’ concerns for their child’s decreased visual acuity during the school years, as the main outcome, were picked up from yearly questionnaires performed for the Longitudinal Survey of Newborns in the Twenty-First Century involving all babies born in Japan during either of two periods: between January 10 and 17, 2001 or between July 10 and 17, 2001 (N = 47,015). Results Television-/video-watching as the main form of play of children at the ages of 1.5 years and 2.5 years was significantly associated with parents’ concerns for their child’s decreased visual acuity raised once or more in six surveys conducted between the ages of 7 and 12 years (odds ratio, 1.1 and 1.09; 95% CI 1.05–1.15 and 1.04–1.14, respectively). The association remained significant after adjustment for confounding variables, including child’s sex, preterm birth, multiple birth, mother’s age at delivery, mother’s and father’s education, and residential area. Longer daily duration of television-watching at 2.5 years was significantly associated with concerns for the child’s decreased visual acuity between the ages of 7 and 12 years, but not at the ages of 3.5, 4.5, and 5.5 years. The association remained significant in a sensitivity analysis of 28,820 children who participated in all six surveys. Conclusions Longer daily exposure to television in children in the earlier years of life was associated with parents’ subsequent concerns about decreased visual acuity in their elementary school-aged child

Microscopic description of large-amplitude shape-mixing dynamics with local QRPA inertial functions

We introduce a microscopic approach to derive all the inertial functions in the five-dimensional quadrupole collective Hamiltonian. Local normal modes are evaluated on the constrained mean field in the quasiparticle random-phase approximation in order to derive the inertial functions. The collective Hamiltonians for neutron-rich Mg isotopes are determined with use of this approach, and the shape coexistence/mixing around the N = 20 region is analyzed.Comment: 6 pages, 2 figures, Talk given at International Symposium New Faces of Atomic Nuclei, Okinawa, Japan, Nov. 15-17, 201

Collective Path Connecting the Oblate and Prolate Local Minima in 68Se

By means of the adiabatic self-consistent collective coordinate method and the pairing plus quadrupole interaction, we have obtained the selfconsistent collective path connecting the oblate and prolate local minima in 68Se for the first time. Along the collective path, the triaxial deformation parameter (gamma) changes between 0 and 60 (degree) keeping the axially symmetric deformation parameter (beta) approximately constant, indicating the importance of triaxial deformation dynamics in the oblate-prolate shape coexistence phenomena.Comment: 6 pages including 6 eps figure