Nagoya Institute of Technology

About: Nagoya Institute of Technology is a education organization based out in Nagoya, Japan. It is known for research contribution in the topics: Thin film & Catalysis. The organization has 10766 authors who have published 19140 publications receiving 255696 citations. The organization is also known as: Nagoya Kōgyō Daigaku & Nitech.

Processing and superconducting properties of high-Jc bulk YBaCuO prepared by melt process☆

Abstract: The authors tried to produce high critical current density (Jc) bulk superconducting material by a melt process. It became clear that the grain boundary region acts as a weak-link and causes the low Jc of the sintered material. It was found that highly oriented bulk material can be produced by a melt process in YBaCuO system. The authors obtained samples which contained many fine Y2BaCuO5 (211) phases and no grain boundary throughout a region of several tens of cubic millimeters. By magnetization measurements, it was found that Jc exceeded 104 A/cm2 at 77 K and 1 T, which is a promising value for practical applications.

Flat-band many-body localization and ergodicity breaking in the Creutz ladder

Abstract: We study disorder-free many-body localization in the flat-band Creutz ladder, which was recently realized in cold-atoms in an optical lattice. In a non-interacting case, the flat-band structure of the system leads to a Wannier wavefunction localized on four adjacent lattice sites. In the flat-band regime both with and without interactions, the level spacing analysis exhibits Poisson-like distribution indicating the existence of disorder-free localization. Calculations of the inverse participation ratio support this observation. Interestingly, this type of localization is robust to weak disorders, whereas for strong disorders, the system exhibits a crossover into the conventional disorder-induced many-body localizated phase. Physical picture of this crossover is investigated in detail. We also observe non-ergodic dynamics in the flat-band regime without disorder. The memory of an initial density wave pattern is preserved for long times.

Nonparametric conditional density estimation using piecewise-linear solution path of kernel quantile regression

Abstract: The goal of regression analysis is to describe the stochastic relationship between an input vector x and a scalar output y. This can be achieved by estimating the entire conditional density p(y ∣ x). In this letter, we present a new approach for nonparametric conditional density estimation. We develop a piecewise-linear path-following method for kernel-based quantile regression. It enables us to estimate the cumulative distribution function of p(y ∣ x) in piecewise-linear form for all x in the input domain. Theoretical analyses and experimental results are presented to show the effectiveness of the approach.

Realization of GaAs/AlGaAs Lasers on Si Substrates Using Epitaxial Lateral Overgrowth by Metalorganic Chemical Vapor Deposition

Abstract: In this paper, we report on the fabrication and characterizations of a GaAs-based laser using the epitaxial lateral overgrowth (ELO) technique. ELO is an epitaxial growth technique capable of yielding low-dislocation-density III-V films on Si. To realize the effectivity of this procedure, two types of lasers were fabricated by changing the positions of the top p+-GaAs and metal contact in-line with the ELO layer and in-line with the line seed region. The longer lifetime for the lasers with the top p+-GaAs and metal contact in-line with the ELO layer proves the suitability of the ELO technique.