We investigate the negative modes about Coleman-De Luccia bounces governing vacuum transitions in de Sitter space, with the goal of gaining physical insight into the various anomalous results associated with these that have been reported in the literature. For the case of bounces with radii much less that the horizon distance H −1 we find two distinct regimes, distinguished by the magnitude of the bubble nucleation rate Γ. If Γ/H 4 ≫ 1, then the behavior of the modes contributing to the determinant factors in Γ is much as it is in flat spacetime, and the calculation of Γ goes over smoothly to the flat spacetime calculation as the gravitational coupling is taken to zero. This is not the case if Γ/H 4 ≪ 1. These two regimes correspond to the two possible outcomes of de Sitter vacuum decay -either a rapidly completed transition or non-percolation and eternal inflation.For bounces with radii comparable to the horizon length, we confirm previous results concerning anomalous negative modes with support on the bounce wall. We also find further evidence supporting previous claims, based on thin-wall arguments, of the absence of expected negative modes for a class of bounces that arises when the initial and final vacua are nearly degenerate.
The objective of the study was to investigate the disease-causing mutation in an autosomal dominant Charcot-Marie-Tooth disease type 2 family and examine the clinical and histopathological evaluation. We enrolled a family of Korean origin with axonal Charcot-Marie-Tooth disease neuropathy (FC305; 13 males, six females) and applied genome-wide linkage analysis. Whole exome sequencing was performed for two patients. In addition, sural nerve biopsies were obtained from two patients. Through whole exome sequencing, we identified an average of 20,336 coding variants from two patients. We also found evidence of linkage mapped to chromosome 11p11-11q13.3 (LOD score of 3.6). Among these variants in the linkage region, we detected a novel p.S90W mutation in the Berardinelli-Seip congenital lipodystrophy 2 (BSCL2) gene, after filtering 31 Korean control exomes. Our p.S90W patients had frequent sensory disturbances, pyramidal tract signs, and predominant right thenar muscle atrophy in comparison with reported p.S90L patients. The phenotypic spectra were wide and demonstrated intrafamilial variability. Two patients with different clinical features underwent sural nerve biopsies; the myelinated fiber densities were increased slightly in both patients, which differed from two previous case reports of BSCL2 mutations (p.S90L and p.N88S). This report expands the variability of the clinical spectrum associated with the BSCL2 gene and describes the first family with the p.S90W mutation.
We have investigated a uniaxial anisotropy along the [100] direction of GaMnAs film grown on (001) GaAs. The hysteresis observed in the angular dependence of the planar Hall resistance shifted toward the [010] and [010] directions. This phenomenon was analyzed by introducing an additional uniaxial anisotropy field Hu2 along the [100] direction. The magnitude of Hu2 is much smaller than those of the cubic Hc and uniaxial Hu1 anisotropy fields for this material. The temperature behavior of Hu2 appears to be very similar to that of Hu1, suggesting the possibility that Hu1 and Hu2 have a common origin.
The effect of strain on the magnetic anisotropy of GaMnAs films has been systematically investigated using Hall effect measurements. The magnitude of the strain, which was caused by differences in the lattice constant between the GaMnAs film and buffer layer, was controlled by adjustment of the alloy composition in the GaInAs buffer layer. The in-plane and out-of-plane components of the magnetic anisotropy were obtained from the angular dependence of the planar Hall resistance and the anomalous Hall resistance, respectively. The anisotropy constants obtained allow us to construct a three-dimensional magnetic free energy surface, which provides a clear understanding of the transition behavior of the magnetization between the in-plane and out-of-plane direction in the GaMnAs films.
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