Symmetry breaking caused by large R-charge

We discuss the gauge symmetry breaking via the Hosotani mechanism by using exact results on supersymmetric gauge theories based on the localization method. We use the theories on S^2 x S^1 Euclidean space, and study how the effective potential for the Wilson line phase varies by running an imaginary chemical potential. In order to break the symmetry, we find that large R-charge is necessary. With such large R-charge, we study the phase structure of the theory. In addition, we observed that a finite size effect on our curved space when we take R-charge is not so large.Comment: 20 pages, 7 figures. Typos corrected, Comments on the limit adde

Unidirectional control of optically induced spin waves

Unidirectional control of optically induced spin waves in a rare-earth iron garnet crystal is demonstrated. We observed the interference of two spin-wave packets with different initial phases generated by circularly polarized light pulses. This interference results in unidirectional propagation if the spin-wave sources are spaced apart at 1/4 of the wavelength of the spin waves and the initial phase difference is set to pi/2. The propagating direction of the spin wave is switched by the polarization helicity of the light pulses. Moreover, in a numerical simulation, applying more than two spin-wave sources with a suitable polarization and spot shape, arbitrary manipulation of the spin wave by the phased array method was replicated

High HOMO levels and narrow energy band gaps of dithienogalloles

We synthesized dithieno[3, 2-b:2′, 3′-d]galloles containing four-coordinated gallium atoms. It was found that dithienogalloles had high stability to air and moisture and showed narrower energy-band gaps than dithienosiloles which are commodity materials in organic opto and/or electronic devices. In addition, relatively-higher HOMO levels were observed from dithienogalloles than those of other dithienoheteroles from electrochemical measurements. We experimentally and theoretically demonstrated the electron-donating properties and resonance effects of gallium atoms of dithienogalloles

DEM-CFD simulation for mixing process of binary particles with large size difference in a bubbling fluidized bed

In practical applications of fluidized beds, the size of solid materials is not uniform and large solids coexist with small solids. The large size difference significantly influences the mixing and segregation phenomena in the beds. However, these behaviors are not fully understood. In the present study, a large-scale DEM-CFD coupling simulation (1) for a pseudo-2D bubbling fluidized bed of binary particles with large size difference is performed. Momentum exchange between larger particles and fluid is expressed by fictitious particle method by Tsuji et al. (2). A particle mixture consists of two kinds of spherical particles with 1 mm diameter and 2500 kg/m3 density and 20 mm diameter and 1600 kg/m3 density. The number of the smaller particles is twenty five million and that of the larger particles is five hundred. The particle mixture is initially in completely separated state, and mixing process of the particles is investigated. The snapshot of the simulation result is shown in Fig. 1. We can observe that the large particles are mixed by bubbles occurring in the bed. Please click Additional Files below to see the full abstract

Renormalization group analysis of superradiant growth of self-interacting axion cloud

There are strong interests in considering ultra-light scalar fields (especially axion) around a rapidly rotating black hole because of the possibility of observing gravitational waves from axion condensate (axion cloud) around black holes. Motivated by this consideration, we propose a new method to study the dynamics of an ultra-light scalar field with self-interaction around a rapidly rotating black hole, which uses the dynamical renormalization group method. We find that for relativistic clouds, saturation of the superradiant instability by the scattering of the axion due to the self-interaction does not occur in the weakly non-linear regime when we consider the adiabatic growth of the cloud from a single superradiant mode. This may suggest that for relativistic axion clouds, an explosive phenomenon called the Bosenova may inevitably happen, at least once in its evolutionary history.Comment: 31 pages, 7 figures, 2 table