Initial wave packets and the various power-law decreases of scattered wave packets at long times

The long time behavior of scattered wave packets $\psi (x,t)$ from a finite-range potential is investigated, by assuming $\psi (x,t)$ to be initially located outside the potential. It is then shown that $\psi (x,t)$ can asymptotically decrease in the various power laws at long time, according to its initial characteristics at small momentum. As an application, we consider the square-barrier potential system and demonstrate that $\psi (x,t)$ exhibits the asymptotic behavior $t^{-3/2}$, while another behavior like $t^{-5/2}$ can also appear for another $\psi (x,t)$.Comment: 5 pages, 1 figur

AKARI/IRC Broadband Mid-infrared data as an indicator of Star Formation Rate

AKARI/Infrared Camera (IRC) Point Source Catalog provides a large amount of flux data at {\it S9W} ($9\ {\rm \mu m}$) and {\it L18W} ($18\ {\rm \mu m}$) bands. With the goal of constructing Star-Formation Rate(SFR) calculations using IRC data, we analyzed an IR selected GALEX-SDSS-2MASS-AKARI(IRC/Far-Infrared Surveyor) sample of 153 nearby galaxies. The far-infrared fluxes were obtained from AKARI diffuse maps to correct the underestimation for extended sources raised by the point-spread function photometry. SFRs of these galaxies were derived by the spectral energy distribution fitting program CIGALE. In spite of complicated features contained in these bands, both the {\it S9W} and {\it L18W} emission correlate with the SFR of galaxies. The SFR calibrations using {\it S9W} and {\it L18W} are presented for the first time. These calibrations agree well with previous works based on Spitzer data within the scatters, and should be applicable to dust-rich galaxies.Comment: PASJ, in pres

Energy from the gauge invariant observables

For a classical solution |Psi> in Witten's cubic string field theory, the gauge invariant observable is conjectured to be equal to the difference of the one-point functions of the closed string state corresponding to V, between the trivial vacuum and the one described by |Psi>. For a static solution |Psi>, if V is taken to be the graviton vertex operator with vanishing momentum, the gauge invariant observable is expected to be proportional to the energy of |Psi>. We prove this relation assuming that |Psi> satisfies equation of motion and some regularity conditions. We discuss how this relation can be applied to various solutions obtained recently.Comment: 27 pages; v5: minor revision in section 2, results unchange

Melting Spectral Functions of the Scalar and Vector Mesons in a Holographic QCD Model

We investigate the finite-temperature spectral functions of heavy quarkonia by using the soft-wall AdS/QCD model. We discuss the scalar, the pseudo-scalar, the vector, and the axial-vector mesons and compare their qualitative features of the melting temperature and growing width. We find that the axial-vector meson melts earlier than the vector meson, while there appears only a slight difference between the scalar and pseudo-scalar mesons which also melt earlier than the vector meson.Comment: 27 pages, 10 figure

1 um Excess Sources in the UKIDSS - I. Three T Dwarfs in the SDSS Southern Equatorial Stripe

We report the discovery of two field brown dwarfs, ULAS J0128-0041 and ULAS J0321+0051, and the rediscovery of ULAS J0226+0051 (IfA 0230-Z1), in the Sloan Digital Sky Survey (SDSS) southern equatorial stripe. They are found in the course of our follow-up observation program of 1 um excess sources in the United Kingdom Infrared Telescope Infrared Deep Sky Survey. The Gemini Multi-Object Spectrographs spectra at red optical wavelengths (6500-10500 A) are presented, which reveal that they are early-T dwarfs. The classification is also supported by their optical to near-infrared colors. It is noted that ULAS J0321+0051 is one of the faintest currently known T dwarfs. The estimated distances to the three objects are 50-110 pc, thus they are among the most distant field T dwarfs known. Dense temporal coverage of the target fields achieved by the SDSS-II Supernova Survey allows us to perform a simple time-series analysis, which leads to the finding of significant proper motions of 150-290 mas/yr or the transverse velocities of 40-100 km/s for ULAS J0128-0041 and ULAS J0226+0051. We also find that there are no detectable, long-term (a-few-year) brightness variations above a few times 0.1 mag for the two brown dwarfs.Comment: Accepted for publication in the Astronomical Journal; Typos correcte

Evolution of the Fraction of Clumpy Galaxies at 0.2<z<1.0 in the COSMOS field

Using the Hubble Space Telescope/Advanced Camera for Surveys data in the COSMOS field, we systematically searched clumpy galaxies at 0.2<z<1.0 and investigated the fraction of clumpy galaxies and its evolution as a function of stellar mass, star formation rate (SFR), and specific SFR (SSFR). The fraction of clumpy galaxies in star-forming galaxies with Mstar > 10^9.5 Msun decreases with time from ~0.35 at 0.8<z<1.0 to ~0.05 at 0.2<z<0.4 irrespective of the stellar mass, although the fraction tends to be slightly lower for massive galaxies with Mstar > 10^10.5 Msun at each redshift. On the other hand, the fraction of clumpy galaxies increases with increasing both SFR and SSFR in all the redshift ranges we investigated. In particular, we found that the SSFR dependences of the fractions are similar among galaxies with different stellar masses, and the fraction at a given SSFR does not depend on the stellar mass in each redshift bin. The evolution of the fraction of clumpy galaxies from z~0.9 to z~0.3 seems to be explained by such SSFR dependence of the fraction and the evolution of SSFRs of star-forming galaxies. The fraction at a given SSFR also appears to decrease with time, but this can be due to the effect of the morphological K-correction. We suggest that these results are understood by the gravitational fragmentation model for the formation of giant clumps in disk galaxies, where the gas mass fraction is a crucial parameter.Comment: 14 Pages, 13 Figures, 1 Table, Accepted for publication in Ap

The various power decays of the survival probability at long times for free quantum particle

The long time behaviour of the survival probability of initial state and its dependence on the initial states are considered, for the one dimensional free quantum particle. We derive the asymptotic expansion of the time evolution operator at long times, in terms of the integral operators. This enables us to obtain the asymptotic formula for the survival probability of the initial state $\psi (x)$, which is assumed to decrease sufficiently rapidly at large $|x|$. We then show that the behaviour of the survival probability at long times is determined by that of the initial state $\psi$ at zero momentum $k=0$. Indeed, it is proved that the survival probability can exhibit the various power-decays like $t^{-2m-1}$ for an arbitrary non-negative integers $m$ as $t \to \infty$, corresponding to the initial states with the condition $\hat{\psi} (k) = O(k^m)$ as $k\to 0$.Comment: 15 pages, to appear in J. Phys.