Scalable Spin Amplification with a Gain over a Hundred

We propose a scalable and practical implementation of spin amplification which does not require individual addressing nor a specially tailored spin network. We have demonstrated a gain of 140 in a solid-state nuclear spin system of which the spin polarization has been increased to 0.12 using dynamic nuclear polarization with photoexcited triplet electron spins. Spin amplification scalable to a higher gain opens the door to the single spin measurement for a readout of quantum computers as well as practical applications of nuclear magnetic resonance (NMR) spectroscopy to infinitesimal samples which have been concealed by thermal noise.Comment: 6 pages, 7 figure

H2-decoupling-accelerated H1 spin diffusion in dynamic nuclear polarization with photoexcited triplet electrons

In dynamic nuclear polarization (DNP) experiments applied to organic solids for creating nonequilibrium, high H1 spin polarization, an efficient buildup of H1 polarization is attained by partially deuterating the material of interest with an appropriate H1 concentration. In such a dilute H1 spin system, it is shown that the H1 spin diffusion rate and thereby the buildup efficiency of H1 polarization can further be enhanced by continually applying radiofrequency irradiation for deuterium decoupling during the DNP process. As experimentally confirmed in this work, the electron spin polarization of the photoexcited triplet state is mainly transferred only to those H1 spins, which are in the vicinity of the electron spins, and H1 spin diffusion transports the localized H1 polarization over the whole sample volume. The H1 spin diffusion coefficients are estimated from DNP repetition interval dependence of the initial buildup rate of H1 polarization, and the result indicates that the spin diffusion coefficient is enhanced by a factor of 2 compared to that without H2 decoupling.This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in M. Negoro, K. Nakayama, K. Tateishi, A. Kagawa, K. Takeda, and M. Kitagawa, J. Chem. Phys. 133, 154504 (2010) and may be found at https://doi.org/10.1063/1.3493453

Shimanto geosyncline and Kuroshio paleoland

The late Mesozoic to early Neogene geosyncline in the Outer zone of Southwest Japan has been studied in detail in the Kii Peninsula by the Research Group for the Shimanto Geosyncline. The existence of the Kuroshio Paleoland to the south of the geosyncline was inferred by various sedimentologic evidences. The Shimanto belt in the Kii Peninsula is divided from north to south into three zones of Cretaceous, Eocene and Oligocene to lower Miocene. In these belts thick geosynclinal sediments were accumulated showing coarsening upward. The southward migration of the basin occurred in Cretaceous/Eocene, Eocene/Oligocene, and in early Miocene. In the present paper the reconstruction of paleogeography of the Shimanto geosyncline was attempted and the Kuroshio Paleoland was discussed in relation to the geohistory of the Philippine Sea. In spite of the detailed geologic survey in the Kii Peninsula there is no evidence of large exotic blocks nor tectonic mélanges, and this does not support the plate tectonic model ofthe Pacific-type orogeny for the Shimanto belt.ArticleJournal of Physics of the Earth. 26(suppl):357-366 (1978)journal articl

Universal patterns in sound amplitudes of songs and music genres

We report a statistical analysis over more than eight thousand songs. Specifically, we investigate the probability distribution of the normalized sound amplitudes. Our findings seems to suggest a universal form of distribution which presents a good agreement with a one-parameter stretched Gaussian. We also argue that this parameter can give information on music complexity, and consequently it goes towards classifying songs as well as music genres. Additionally, we present statistical evidences that correlation aspects of the songs are directly related with the non-Gaussian nature of their sound amplitude distributions.Comment: Accepted for publication as a Brief Report in Physical Review

Severe discrepancies between experiment and theory in the superconducting proximity effect

The superconducting proximity effect is investigated for SN double layers in a regime where the resulting transition temperature T_{c} does not depend on the mean free paths of the films and, within limits, not on the transparency of the interface. This regime includes the thin film limit and the normalized initial slope S_{sn}= (d_{s}/T_{s})|dT_{c}/dd_{n}|. The experimental results for T_{c} are compared with a numerical simulation which was recently developed in our group. The results for the SN double layers can be devided into three groups: (i) When N = Cu, Ag, Au, Mg a disagreement between experiment and theory by a factor of the order of three is observed, (ii) When N = Cd, Zn, Al the disagreement between experiment and theory is reduced to a factor of about 1.5, (iii) When N = In, Sn a reasonably good agreement between experiment and theory is observed