The superconductivity transition temperatures Tc(onset) of 11.4 K and Tc(offset) of 7.4 K, which are the highest in diamond at present, are realized on homoepitaxially grown (111) diamond films with a high boron doping concentration of 8.4E21 cm-3 (4.7 atomic percent). Tc values of (111) diamond films are more than twice as high as those of (100) films at the equivalent boron concentration. The Tc of boron-doped (111) diamond increases as the boron content increases up to the maximum incorporated concentration and is agrees with the value estimated using McMillan's equation. The advantageous Tc for (111) diamond films is due to the higher carrier concentration which exceeds its boron concentration.

Hitoshi Umezawa Tomohiro Takenouchi Yoshihiko Takano Kensaku Kobayashi Masanori Nagao Isao Sakaguchi Minoru Tachiki Takeshi Hatano Guofang Zhong Masashi Tachiki Hiroshi Kawarada

We consider what occurs when we remove one of the compositeness conditions proposed by Bardeen, Hill and Lindner that leads to predictions for the top quark mass conflicting with the experimental value. Through this consideration the condition for the Higgs particle to be the composite particle is reconsidered. We show that in this case, (I) the Higgs-Yukawa system of the standard model becomes equivalent to a non-local four-fermi system at a high-energy scale $\Lambda$, (II) The Higgs-Yukawa sector of the model becomes useless above the scale because the vacuum state cannot be defined. We regard the two phenomena as indications of the compositeness of the Higgs particle. It is suggested that the new physics above $\Lambda$ contains bi-local fields.

Eizou Umezawa

The bi-local model of hadrons is studied from the viewpoint of non-commutative geometry formulated so that Higgs-like scalar fields play the role of a bridge, the bi-local fields, connecting different spacetime points. We show that the resultant action for Higgs-like scalar fields has a structure similar to that of the linear sigma model. According to this formalism, we can deduce the dual nature of meson fields as the Nambu-Goldstone bosons associated with chiral symmetry breaking and bound states of quarks.

Shigefumi Naka Shinji Abe Eizou Umezawa Tetsu Matsufuji

In a series of two papers we present the theoretical results of $\pi N$/meson-baryon scattering in the Kadyshevsky formalism. In this paper the results are given for meson exchange diagrams. On the formal side we show, by means of an example, how general couplings, i.e. couplings containing multiple derivatives and/or higher spin fields, should be treated. We do this by introducing and applying the Takahashi-Umezawa and the Gross-Jackiw method. For practical purposes we introduce the $\bar{P}$ method. We also show how the Takashashi-Umezawa method can be derived using the theory of Bogoliubov and collaborators and the Gross-Jackiw method is also used to study the $n$-dependence of the Kadyshevsky integral equation. Last but not least we present the second quantization procedure of the quasi particle in Kadyshevsky formalism.

J. W. Wagenaar T. A. Rijken

We empirically investigate the best trade-off between sparse and uniformly-weighted multiple kernel learning (MKL) using the elastic-net regularization on real and simulated datasets. We find that the best trade-off parameter depends not only on the sparsity of the true kernel-weight spectrum but also on the linear dependence among kernels and the number of samples.

Ryota Tomioka Taiji Suzuki

In the estimation of the mean matrix in a multivariate normal distribution, the generalized Bayes estimators with closed forms are provided, and the sufficient conditions for their minimaxity are derived relative to both matrix and scalar quadratic loss functions. The generalized Bayes estimators of the covariance matrix are also given with closed forms, and the dominance properties are discussed for the Stein loss function.

Ryota Yuasa Tatsuya Kubokawa

We provide a formula to reconstruct bulk spacetime metrics inside black holes by the time dependence of complexity in the dual quantum field theory, based on the complexity=volume (CV) conjecture in the holographic duality.

Koji Hashimoto Ryota Watanabe

In this paper, we investigate necessary and sufficient conditions on the boundedness of composition operators on the Orlicz-Morrey spaces. The results of boundedness include Lebesgue and generalized Morrey spaces as special cases. Further, we characterize the boundedness of composition operators on the weak Orlicz-Morrey spaces. The weak Orlicz-Morrey spaces contain the Orlicz-Morrey spaces.

Masahiro Ikeda Isao Ishikawa Ryota Kawasumi

We give a constructive counterpart of the theorem of Andrunakievi\v{c} and Rjabuhin, which states that every reduced ring is a subdirect product of domains. As an application, we extract a constructive proof of the fact that every ring $A$ satisfying $\forall x\in A. x^3=x$ is commutative from a classical proof. We also prove a similar result for semiprime ideals.

Ryota Kuroki

Let $E$ be an elliptic curve defined over $\mathbb{Q}$ with supersingular reduction at $p \geq 5$, and $K$ be an imaginary quadratic field such that $p$ is inert in $K/\mathbb{Q}$. In this paper, we prove the analogous of the ``weak'' Mazur--Tate refined conjecture for an anticyclotomic tower over $K$ using the result by A. Burungale--K. B\"{u}y\"{u}kboduk--A. Lei.

Ryota Shii