Sophia University

About: Sophia University is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Nonlinear system & Catalysis. The organization has 4986 authors who have published 7657 publications receiving 106567 citations. The organization is also known as: Jōchi Daigaku.

Single-reference high-precision mass measurement with a multireflection time-of-flight mass spectrograph

Abstract: A multireflection time-of-flight mass spectrograph, competitive with Penning trap mass spectrometers, has been built at RIKEN. We have performed a first online mass measurement, using ${}^{8}$Li${}^{+}$ (${T}_{1/2}=838$ ms). A new analysis method has been realized, with which, using only ${}^{12}$C${}^{+}$ references, the mass excess of ${}^{8}$Li was accurately determined to be 20 947.6(15)(34) keV ($\ensuremath{\delta}m/m=6.6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}$). The speed, precision, and accuracy of this first online measurement exemplifies the potential for using this new type of mass spectrograph for precision measurements of short-lived nuclei.

Deep Learning the Quantum Phase Transitions in Random Electron Systems: Applications to Three Dimensions

Abstract: Three-dimensional random electron systems undergo quantum phase transitions and show rich phase diagrams. Examples of the phases are the band gap insulator, Anderson insulator, strong and weak topological insulators, Weyl semimetal, and diffusive metal. As in the previous paper on two-dimensional quantum phase transitions [J. Phys. Soc. Jpn. vol. 85, 123706 (2016)], we use an image recognition algorithm based on a multilayered convolutional neural network to identify which phase the eigenfunction belongs to. The Anderson model for localization-delocalization transition, the Wilson--Dirac model for topological insulators, and the layered Chern insulator model for Weyl semimetal are studied. The situation where the standard transfer matrix approach is not applicable is also treated by this method.

Design and properties of functional zwitterions derived from ionic liquids

Abstract: A zwitterion, an ion pair where cation and anion are covalently tethered, is known to be a type of salt. These ions have not been recognised as interesting, but they are physicochemically unique and fascinating ions. In the present review, some functional zwitterions derived from ionic liquids are mentioned to emphasise the usefulness of the tethering of the component cations and anions of ionic liquids. Basic properties, advantages and disadvantages after the functional design of zwitterions, and some applications are summarised.

Relativistic Thermal Bremsstrahlung Gaunt Factor for the Intracluster Plasma. II. Analytic Fitting Formulae

Abstract: We present accurate analytic fitting formulae which summarize the results of the recent calculation by Nozawa, Itoh and Kohyama on the relativistic thermal bremsstrahlung Gaunt factor for the intracluster plasma. The fitting is carried out for Z = 1 to 28, 6.0 < log T < 8.5, -4.0 < log (omega/kT) < 1.0, where Z is the charge number of the ion, T is the temperature, and omega is the angular frequency of the emitted photon. The present analytic fitting formulae will be useful for the analysis of the X-ray emission which comes from the intracluster plasma as well as the other X-ray sources.

Momentum transport away from a jet in an expanding nuclear medium

Abstract: We study the transport dynamics of momenta deposited from jets in ultrarelativistic heavy-ion collisions. Assuming that the high-energy partons traverse expanding quark-gluon fluids and are subject to lose their energy and momentum, we simulate dijet asymmetric events by solving relativistic hydrodynamic equations numerically without linearization in the fully $(3+1)$-dimensional coordinate. Mach cones are formed and strongly broadened by radial flow of the background medium. As a result, the yield of low-${p}_{T}$ particles increases at large angles from the jet axis and compensates the dijet momentum imbalance inside the jet cone. This provides an intimate link between the medium excitation by jets and results in dijet asymmetric events observed by the CMS Collaboration.