Higgs-Inflaton Potential in Higher-Dimensional SUSY Gauge Theories

We study the possibility that the Higgs and the inflaton are the same single field or cousins arising from the extra space components of some higher-dimensional gauge field. We take 5D supersymmetric gauge theory with a matter compactified on S^1 as a toy model and evaluate the one-loop contribution to the Higgs-inflaton potential. Our gauge-Higgs-inflaton unification picture applied to the gauge field of intermediate energy scale (\sim 10^{13} GeV) can explain the observed inflation parameters without fine-tuning.Comment: 10 pages, 3 figures, Title and abstract are slightly changed. Our results are also modifie

First results in terrain mapping for a roving planetary explorer

To perform planetary exploration without human supervision, a complete autonomous rover must be able to model its environment while exploring its surroundings. Researchers present a new algorithm to construct a geometric terrain representation from a single range image. The form of the representation is an elevation map that includes uncertainty, unknown areas, and local features. By virtue of working in spherical-polar space, the algorithm is independent of the desired map resolution and the orientation of the sensor, unlike other algorithms that work in Cartesian space. They also describe new methods to evaluate regions of the constructed elevation maps to support legged locomotion over rough terrain

The Gauge Hierarchy Problem and Higher Dimensional Gauge Theories

We report on an attempt to solve the gauge hierarchy problem in the framework of higher dimensional gauge theories. Both classical Higgs mass and quadratically divergent quantum correction to the mass are argued to vanish. Hence the hierarchy problem in its original sense is solved. The remaining finite mass correction is shown to depend crucially on the choice of boundary condition for matter fields, and a way to fix it dynamically is presented. We also point out that on the simply-connected space $S^2$ even the finite mass correction vanishes.Comment: LaTeX2e. 12 pages, 3 Postscript figures; Added references, some comment

Cosmological Constraints on Neutrino Injection

We derive general constraints on the relic abundances of a long-lived particle which mainly decays into a neutrino (and something else) at cosmological time scales. Such an exotic particle may show up in various particle-physics models based on physics beyond the standard model. The constraints are obtained from big-bang nucleosynthesis, cosmic microwave background and diffuse neutrino and photon fluxes, depending on the lifetime and the electromagnetic and hadronic branching ratios.Comment: 33 pages, 23 figure

Big-Bang Nucleosynthesis with Unstable Gravitino and Upper Bound on the Reheating Temperature

We study the effects of the unstable gravitino on the big-bang nucleosynthesis. If the gravitino mass is smaller than \sim 10 TeV, primordial gravitinos produced after the inflation are likely to decay after the big-bang nucleosynthesis starts, and the light element abundances may be significantly affected by the hadro- and photo-dissociation processes as well as by the p n conversion process. We calculate the light element abundances and derived upper bound on the reheating temperature after the inflation. In our analysis, we calculate the decay parameters of the gravitino (i.e., lifetime and branching ratios) in detail. In addition, we performed a systematic study of the hadron spectrum produced by the gravitino decay, taking account of all the hadrons produced by the decay products of the gravitino (including the daughter superparticles). We discuss the model-dependence of the upper bound on the reheating temperature.Comment: 32 pages, 11 figure

Characterization of Low Temperature Soluble Polyaniline

Because the charging of polyaniline films occurs in the bulk of the material rather than exclusively at the polymer-electrolyte interface, the use of thick polymer films for battery applications is justifiable. Here, we present a method for producing soluble polyaniline which can be cast to form free-standing films. Investigation by scanning electron microsopy (SEM) has shown that these films are significantly more compact than those made by standard electropolymerization

K-Band Galaxy Counts in the South Galactic Pole Region

We present new K-band galaxy number counts from K=13 to 20.5 obtained from $K'$-band surveys in the south galactic pole region, which cover 180.8 arcmin$^2$ to a limiting magnitude of K=19, and 2.21 arcmin$^2$ to K=21. These are currently the most precise K-band galaxy counts at $17.5<K<19.0$ because the area of coverage is largest among the existing surveys for this magnitude range. The completeness and photometry corrections are estimated from the recovery of simulated galaxy and stellar profiles added to the obtained field image. Many simulations were carried out to construct a probability matrix which corrects the galaxy counts at the faint-end magnitudes of the surveys so the corrected counts can be compared with other observations. The K-band star counts in the south galactic pole region to $K=17.25$ are also presented for use to constrain the vertical structure of the Galaxy.Comment: accepted for publication in ApJ. 26 pages with 4 figures, and 2 plates are not included. All documents and figures can be retrieved from http://merope.mtk.nao.ac.jp/~minezaki/mine_paper.htm

Large scale simulation of quantum-mechanical molecular dynamics for nano-polycrystalline diamond

Quantum-mechanical molecular-dynamics simulations are carried out to explore possible precursor states of nano-polycrystalline diamond, a novel ultra-hard material produced directly from graphite. Large-scale simulation with 10^5 atoms is realized by using the ' order-N' simulation code 'ELSES' (http://www.elses.jp). The simulation starts with a diamond structure that contains initial structural defects and results in a mixture of graphite(sp^2)-like and diamond(sp^3)-like regions as nano-meter-scale domains. We speculate that the domains are metastable and are possible candidates of the precursor structures.Comment: 4 pages 2 figures. A PDF file in better graphics is available at http://www.elses.jp

Temperature Dependence of Zero-Bias Resistances of a Single Resistance-Shunted Josephson Junction

Zero-bias resistances of a single resistance-shunted Josephson junction are calculated as a function of the temperature by means of the path-integral Monte Carlo method in case a charging energy $E_{\rm C}$ is comparable with a Josephson energy $E_{\rm J}$. The low-temperature behavior of the zero-bias resistance changes around $\alpha=R_{\rm Q}/R_{\rm S}=1$, where $R_{\rm S}$ is a shunt resistance and $R_{\rm Q}=h/(2e)^2$. The temperature dependence of the zero-bias resistance shows a power-law-like behavior whose exponent depends on $E_{\rm J}/E_{\rm C}$. These results are compared with the experiments on resistance-shunted Josephson junctions

Hybridization Mechanism for Cohesion of Cd-based Quasicrystals

Cohesion mechanism of cubic approximant crystals of newly discovered binary quasicrystals, Cd$_6$M (M=Yb and Ca), are studied theoretically. It is found that stabilization due to alloying is obtained if M is an element with low-lying unoccupied $d$ states. This leads to conclusion that the cohesion of the Cd-based compounds is due to the hybridization of the $d$ states of Yb and Ca with a wide $sp$ band. %unlike known stable quasicrystals without transition elements %such as Al-Li-Cu and Zn-Mg-RE (RE:rare earth). Although a diameter of the Fermi sphere coincides with the strong Bragg peaks for Cd-Yb and Cd-Ca, the Hume-Rothery mechanism does not play a principal role in the stability because neither distinct pseudogap nor stabilization due to alloying is obtained for isostructural Cd-Mg. In addition to the electronic origin, matching of the atomic size is very crucial for the quasicrystal formation of the Cd-based compounds. It is suggested that the glue atoms, which do not participate in the icosahedral cluster, play an important role in stabilization of the compound.Comment: 4 pages, 2 figure