Theory of resonant spin Hall effect

A biref review is presented on resonant spin Hall effect, where a tiny external electric field induces a saturated spin Hall current in a 2-dimensional electron or hole gas in a perpendicular magnetic field. The phenomenon is attributted to the energy level crossing associated with the spin-orbit coupling and the Zeeman splitting. We summarize recent theoretical development of the effect in various systems and discuss possible experiments to observe the effect.Comment: 5 pages with 1 figure

"Public Debt and Economic Growth in an Aging Japan"

This@paper@examines@the@effects of the demographic change and the government debt policy in Japan on economic growth and economic welfare, particularly by taking into account the existing public pension scheme as well as national medical expenditure through the existing public health insurance, wherea computational overlapping generations model is used within a general equilibrium context. One of the main results of this paper is that the tax burden (GDP) ratio will increase up to about 36%, and the social security burden (GDP) ratio will increase up to 23.3% in 2050, even though the government tries to have a positive primary balance by 2010. The ratio of public health insurance bene?ts to GDP is expected to increase at 1% every 10years, and the ratio will be around 9.6%in 2050. The 2004 public pension reform will successfully result in a 13 point decrease in the contribution rate from 36.44% to 23.53%, and reduce the social security burden (GDP) ratio by about 8 points from 23.27% to 15.02% in 2050, compared with the benchmark case.

Public Debt and Economic Growth in an Aging Japan

This?paper?examines?the?effects of the demographic change and the government debt policy in Japan on economic growth and economic welfare, particularly by taking into account the existing public pension scheme as well as national medical expenditure through the existing public health insurance, wherea computational overlapping generations model is used within a general equilibrium context. One of the main results of this paper is that the tax burden (GDP) ratio will increase up to about 36%, and the social security burden (GDP) ratio will increase up to 23.3% in 2050, even though the government tries to have a positive primary balance by 2010. The ratio of public health insurance bene?ts to GDP is expected to increase at 1% every 10years, and the ratio will be around 9.6%in 2050. The 2004 public pension reform will successfully result in a 13 point decrease in the contribution rate from 36.44% to 23.53%, and reduce the social security burden (GDP) ratio by about 8 points from 23.27% to 15.02% in 2050, compared with the benchmark case.

Neutrino emissions in all flavors up to the pre-bounce of massive stars and the possibility of their detections

This paper is a sequel to our previous one (Kato et al.2015), which calculated the luminosities and spectra of electron-type anti-neutrinos ($\bar{\nu}_e$'s) from the progenitors of core-collapse supernovae. Expecting that a capability to detect electron-type neutrinos ($\nu_e$'s) will increase dramatically with the emergence of liquid-argon detectors such as DUNE, we broaden the scope in this study to include all-flavors of neutrinos emitted from the pre-bounce phase. We pick up three progenitor models of an electron capture supernova (ECSN) and iron-core collapse supernovae (FeCCSNe). We find that the number luminosities reach $\sim10^{57} \mathrm{s^{-1}}$ and $\sim10^{53} \mathrm{s^{-1}}$ at maximum for $\nu_e$ and $\bar{\nu}_e$, respectively. We also estimate the numbers of detection events at terrestrial neutrino detectors including DUNE, taking flavor oscillations into account and assuming the distance to the progenitors to be 200 pc. It is demonstrated that $\bar{\nu}_e$'s from the ECSN-progenitor will be undetected at almost all detectors, whereas we will be able to observe $\gtrsim$15900 $\nu_e$'s at DUNE for the inverted mass hierarchy. From the FeCCSN-progenitors, the number of $\bar{\nu}_e$ events will be largest for JUNO, 200-900 $\bar{\nu}_e$'s, depending on the mass hierarchy whereas the number of $\nu_e$ events at DUNE is $\gtrsim$2100 for the inverted mass hierarchy. These results imply that the detection of $\bar{\nu}_e$'s is useful to distinguish FeCCSN- from ECSN-progenitors, while $\nu_e$'s will provide us with detailed information on the collapse phase regardless of the type and mass of progenitor.Comment: 22 pages, 14 figures, 4 tables, accepted to Ap

Tracing Monopoles and Anti-monopoles in a Magnetic Hedgehog Lattice

The magnetic hedgehog lattice (HL), which was recently discovered in the $B$20-type chiral magnet MnSi$_{1-x}$Ge$_x$, is a topological spin texture with a periodic array of magnetic monopoles and anti-monopoles. Within the continuum approximation, the monopoles and anti-monopoles are predicted to move, collide, and pair annihilate in an applied magnetic field, but it remains unclear how the lattice discretization affects their motions. Here, we study the trajectories of monopoles and anti-monopoles in a lattice system by simulated annealing with field sweep. We show that the monopoles and anti-monopoles move and repel before pair annihilations. We also clarify that their motions are closely related with the field dependence of the scalar spin chirality.Comment: 6 pages, 5 figure