Modified Armijo line-search in Riemannian optimization with reduced computational cost

In this paper, we propose a new line-search method that improves the ordinary Armijo line-search in Riemannian optimization. For optimization problems on Riemannian manifolds, many types of globally convergent algorithms have been proposed, and they are often equipped with the Armijo line-search in Riemannian optimization for global convergence. Such existing methods need the computation of a retraction regarding the search direction for each iteration. On the other hand, the proposed line-search decreases the computational cost by incorporating a new strategy that computes the retraction only if a promising candidate for the step length is found. We further present a Riemannian Newton method with the new line-search strategy and prove its global convergence

Five Consecutive Cases of Liquefied Aftercataract: Impact of Nd:YAG Laser Capsulotomy on Refraction and High-Order Aberrations

For five consecutive eyes from five patients with liquefied aftercataract, Nd:YAG laser treatment significantly reduced high-order aberrations. Two eyes showing a reduction in positive spherical-like aberrations after treatment showed a postoperative myopic shift, while three eyes showing no change in spherical-like aberrations demonstrated hyperopic or only a slight myopic shift

On the Effects of Cutaneous Stimulations upon EEG, Respiratory and Muscular Activities of Frog

The effects produced in the average frequency-patterns of EEGs from the olfactory bulb and forebrain of frog (Rana nigromaculata) by cutaneous pressure stimulations that are spatio-temporally constant in intensity and by repetitive tactile stimulations which are variable in intensity were observed. The changes in the respiratory movements and muscle activity produced by these stimulations were also observed and correlated with the EEG changes. In correspondence with the "inhibitory" and augmentative effects in movements, muscle tone and respiration, decrease and, respectively, increase of the EEG potentials in both the olfactory bulb and forebrain were observed during the application of the two types of stimulation. EEG potentials in the forebrain were augmented more effectively by contralateral than by ipsilateral tactile stimulation

Observation of the Fano-Kondo Anti-Resonance in a Quantum Wire with a Side-Coupled Quantum Dot

We have observed the Fano-Kondo anti-resonance in a quantum wire with a side-coupled quantum dot. In a weak coupling regime, dips due to the Fano effect appeared. As the coupling strength increased, conductance in the regions between the dips decreased alternately. From the temperature dependence and the response to the magnetic field, we conclude that the conductance reduction is due to the Fano-Kondo anti-resonance. At a Kondo valley with the Fano parameter $q\approx 0$, the phase shift is locked to $\pi/2$ against the gate voltage when the system is close to the unitary limit in agreement with theoretical predictions by Gerland {\it et al.} [Phys. Rev. Lett. {\bf 84}, 3710 (2000)].Comment: 4 pages, 4 figure

Some Observations on EEG Response to Photic Flicker Stimulation

By applying a combined method of crosscorrelation and frequency analysis to EEG tracings, the average response patterns to photic flicker stimulation with a frequency in the alpha wave range were sorted out, even when the application of the frequency analysis only could not separate the response from the irrelevant oscillations to the stimulation. During the stimulation, low volage fast pattern (alpha blocking state), in which the response was hard to recognize by visual inspection of the tracing, occurred in the EEG tracings from time to time. In the frequency spectra of them, however, not only a peak at the stimulating frequency, but the other ones at slightly higher frequency and sometimes with subharmonic frequency were appeared to suggest they are the response to the stimulation, though they are far lower than the peak of the dominant alpha wave before the initiation of the stimulation, rised up at the stimulating frequency in the power spectra of the crosscorrelogram between the stimulation and the tracing to indicate the other peaks were not related response, at least directly, to the stimulation, but by others

Imprinting spatial helicity structure of vector vortex beam on spin texture in semiconductors

We present the transfer of the spatially variant polarization of topologically structured light to the spatial spin texture in a semiconductor quantum well. The electron spin texture, which is a circular pattern with repeating spin-up and spin-down states whose repetition rate is determined by the topological charge, is directly excited by a vector vortex beam with a spatial helicity structure. The generated spin texture efficiently evolves into a helical spin wave pattern owing to the spin-orbit effective magnetic fields in the persistent spin helix state by controlling the spatial wave number of the excited spin mode. By tuning the repetition length and azimuthal angle, we simultaneously generate helical spin waves with opposite phases by a single beam.Comment: 6 pages, 4 figure

Seismic Velocity Structure in and around the Japanese Island Arc Derived from Seismic Tomography Including NIED MOWLAS Hi-net and S-net Data

Japanese Islands are composed of four plates, with two oceanic plates subducting beneath the two continental plates. In 2016 the National Research Institute for Earth Science and Disaster Resilience (NIED) Seafloor Observation Network for Earthquakes and Tsunamis along the Japan Trench (S-net) started seismic observation of the offshore Hokkaido to Boso region in the Pacific Ocean, and Dense Oceanfloor Network System for Earthquakes and Tsunamis (DONET) was transferred to NIED. We add the NIED S-net and DONET datasets to NIED high-sensitivity seismograph network (Hi-net) and full range seismograph network (F-net) datasets used in the previous study and obtain the three-dimensional seismic velocity structure beneath the Pacific Ocean as well as Japanese Islands. NIED S-net data dramatically improve the resolution beneath the Pacific Ocean at depths of 10–20 km because the seismic stations are located above the earthquakes and on the east side of the Japan Trench. We find a NS high-Vp zone at depths of 20–30 km. The 2018 Eastern Iburi earthquake occurred below the northern part of this high-V zone. The coseismic slip plane of the 2011 Tohoku-oki earthquake has low Vp/Vs, but its large slip region has high Vp. The broad low-Vp/Vs region may play a role in large earthquake occurrence

Solving the Bethe-Salpeter equation for bound states of scalar theories in Minkowski space

We apply the perturbation theory integral representation (PTIR) to solve for the bound state Bethe-Salpeter (BS) vertex for an arbitrary scattering kernel, without the need for any Wick rotation. The results derived are applicable to any scalar field theory (without derivative coupling). It is shown that solving directly for the BS vertex, rather than the BS amplitude, has several major advantages, notably its relative simplicity and superior numerical accuracy. In order to illustrate the generality of the approach we obtain numerical solutions using this formalism for a number of scattering kernels, including cases where the Wick rotation is not possible.Comment: 28 pages of LaTeX, uses psfig.sty with 5 figures. Also available via WWW at http://www.physics.adelaide.edu.au/theory/papers/ADP-97-10.T248-abs.html or via anonymous ftp at ftp://bragg.physics.adelaide.edu.au/pub/theory/ADP-97-10.T248.ps A number of (crucial) typographical errors in Appendix C corrected. To be published in Phys. Rev. D, October 199