Quantum field and uniformly accelerated oscillator

We present an exact treatment of the influences on a quantum scalar field in its Minkowski vacuum state induced by coupling of the field to a uniformly accelerated harmonic oscillator. We show that there are no radiation from the oscillator in the point of view of a uniformly accelerating observer. On the other hand, there are radiations in the point of view of an inertial observer. It is shown that Einstein-Podolsky-Rosen (EPR) like correlations of Rindler particles in Minkowski vacuum states are modified by a phase factor in front of the momentum-symmetric Rindler operators. The exact quantization of a time-dependent oscillator coupled to a massless scalar field was given.Comment: 28 pages, LaTe

Radiation from a uniformly accelerating harmonic oscillator

We consider a radiation from a uniformly accelerating harmonic oscillator whose minimal coupling to the scalar field changes suddenly. The exact time evolutions of the quantum operators are given in terms of a classical solution of a forced harmonic oscillator. After the jumping of the coupling constant there occurs a fast absorption of energy into the oscillator, and then a slow emission follows. Here the absorbed energy is independent of the acceleration and proportional to the log of a high momentum cutoff of the field. The emitted energy depends on the acceleration and also proportional to the log of the cutoff. Especially, if the coupling is comparable to the natural frequency of the detector ($e^2/(4m) \sim \omega_0$) enormous energies are radiated away from the oscillator.Comment: 26 pages, 1 eps figure, RevTeX, minor correction in grammar, add a discussio

Core-Level X-Ray Photoemission Satellites in Ruthenates: A New Mechanism Revealing the Mott Transition

Ru 3d core-level x-ray photoemission spectra of various ruthenates are examined. They show in general two-peak structures, which can be assigned as the screened and unscreened peaks. The screened peak is absent in a Mott insulator, but develops into a main peak in the metallic regime. This spectral behavior is well explained by the dynamical mean-field theory calculation for the single-band Hubbard model with on-site core-hole potential using the exact diagonalization method. The new mechanism of the core-level photoemission satellite can be utilized to reveal the Mott transition phenomenon in various strongly correlated electron systems, especially in nano-scale devices and phase-separated materials.Comment: 4 pages, 5 figures, submitted to PR

Black string and velocity frame dragging

We investigate velocity frame dragging with the boosted Schwarzschild black string solution and the boosted Kaluza-Klein bubble solution, in which a translational symmetry along the boosted $z$-coordinate is implemented. The velocity frame dragging effect can be nullified by the motion of an observer using the boost symmetry along the $z-$coordinate if it is not compact. However, in spacetime with the compact $z-$coordinate, we show that the effect cannot be removed since the compactification breaks the global Lorentz boost symmetry. As a result, the comoving velocity is dependent on $r$ and the momentum parameter along the $z-$coordinate becomes an observer independent characteristic quantity of the black string and bubble solutions. The dragging induces a spherical ergo-region around the black string.Comment: 8 pages, no figure, some correction

X-ray absorption spectroscopy study of diluted magnetic semiconductors: Zn1-xMxSe (M = Mn, Fe, Co) and Zn1-xMnxY (Y = Se, Te)

We have investigated 3d electronic states of doped transition metals in II-VI diluted magnetic semiconductors, Zn1-xMxSe (M = Mn, Fe, Co) and Zn1-xMnxY (Y = Se, Te), using the transition-metal L2,3-edge X-ray absorption spectroscopy (XAS) measurements. In order to explain the XAS spectra, we employed a tetragonal cluster model calculation, which includes not only the full ionic multiplet structure but also configuration interaction (CI). The results show that CI is essential to describe the experimental spectra adequately, indicating the strong hybridization between the transition metal 3d and the ligand p orbitals. In the study of Zn1-xMnxY (Y = Se, Te), we also found considerable spectral change in the Mn L2,3-edge XAS spectra for different ligands, confirming the importance of the hybridization effects in these materials.Comment: This paper consists of 22 pages including 4 figures. This paper is submitted to Physical Review

Far-infrared transmission studies of c-axis oriented superconducting MgB2 thin film

We reported far-infrared transmission measurements on a c-axis oriented superconducting MgB$_{2}$ thin film in the frequency range of 30 $\sim$ 250 cm$^{-1}$. We found that these measurements were sensitive to values of scattering rate $1/\tau$ and superconducting gap $2\Delta$. By fitting the experimental transmission spectra at 40 K and below, we obtained $1/\tau =$ (700 $\sim$ 1000) cm$^{-1}$ and $2\Delta (0)\cong$ 42 cm$^{-1}$. These two quantities suggested that MgB$_{2}$ belong to the dirty limit.Comment: submitted at May

A Whole Genome Association Study on Meat Palatability in Hanwoo

A whole genome association (WGA) study was carried out to find quantitative trait loci (QTL) for sensory evaluation traits in Hanwoo. Carcass samples of 250 Hanwoo steers were collected from National Agricultural Cooperative Livestock Research Institute, Ansung, Gyeonggi province, Korea, between 2011 and 2012 and genotyped with the Affymetrix Bovine Axiom Array 640K single nucleotide polymorphism (SNP) chip. Among the SNPs in the chip, a total of 322,160 SNPs were chosen after quality control tests. After adjusting for the effects of age, slaughter-year-season, and polygenic effects using genome relationship matrix, the corrected phenotypes for the sensory evaluation measurements were regressed on each SNP using a simple linear regression additive based model. A total of 1,631 SNPs were detected for color, aroma, tenderness, juiciness and palatability at 0.1% comparison-wise level. Among the significant SNPs, the best set of 52 SNP markers were chosen using a forward regression procedure at 0.05 level, among which the sets of 8, 14, 11, 10, and 9 SNPs were determined for the respectively sensory evaluation traits. The sets of significant SNPs explained 18% to 31% of phenotypic variance. Three SNPs were pleiotropic, i.e. AX-26703353 and AX-26742891 that were located at 101 and 110 Mb of BTA6, respectively, influencing tenderness, juiciness and palatability, while AX-18624743 at 3 Mb of BTA10 affected tenderness and palatability. Our results suggest that some QTL for sensory measures are segregating in a Hanwoo steer population. Additional WGA studies on fatty acid and nutritional components as well as the sensory panels are in process to characterize genetic architecture of meat quality and palatability in Hanwoo

High current-carrying capability in c-axis-oriented superconducting MgB2 thin films

In high-quality c-axis-oriented MgB2 thin films, we observed high critical current densities (Jc) of 16 MA/cm^2 at 15 K under self fields comparable to those of cuprate high-temperature superconductors. The extrapolated value of Jc at 5 K was estimated to be 40 MA/cm^2. For a magnetic field of 5 T, a Jc of 0.1 MA/cm^2 was detected at 15 K, suggesting that this compound would be a very promising candidate for practical applications at high temperature and lower power consumption. The vortex-glass phase is considered to be a possible explanation for the observed high current-carrying capability.Comment: 3 pages and 4 figures, to be published in Physical Review Letter

Evaluation of Genome Based Estimated Breeding Values for Meat Quality in a Berkshire Population Using High Density Single Nucleotide Polymorphism Chips

The accuracy of genomic estimated breeding values (GEBV) was evaluated for sixteen meat quality traits in a Berkshire population (n = 1,191) that was collected from Dasan breeding farm, Namwon, Korea. The animals were genotyped with the Illumina porcine 62 K single nucleotide polymorphism (SNP) bead chips, in which a set of 36,605 SNPs were available after quality control tests. Two methods were applied to evaluate GEBV accuracies, i.e. genome based linear unbiased prediction method (GBLUP) and Bayes B, using ASREML 3.0 and Gensel 4.0 software, respectively. The traits composed different sets of training (both genotypes and phenotypes) and testing (genotypes only) data. Under the GBLUP model, the GEBV accuracies for the training data ranged from 0.42±0.08 for collagen to 0.75±0.02 for water holding capacity with an average of 0.65±0.04 across all the traits. Under the Bayes B model, the GEBV accuracy ranged from 0.10±0.14 for National Pork Producers Council (NPCC) marbling score to 0.76±0.04 for drip loss, with an average of 0.49±0.10. For the testing samples, the GEBV accuracy had an average of 0.46±0.10 under the GBLUP model, ranging from 0.20±0.18 for protein to 0.65±0.06 for drip loss. Under the Bayes B model, the GEBV accuracy ranged from 0.04±0.09 for NPCC marbling score to 0.72±0.05 for drip loss with an average of 0.38±0.13. The GEBV accuracy increased with the size of the training data and heritability. In general, the GEBV accuracies under the Bayes B model were lower than under the GBLUP model, especially when the training sample size was small. Our results suggest that a much greater training sample size is needed to get better GEBV accuracies for the testing samples

Phonon structure in I-V characteristic of MgB2_{2} point-contacts

The search of the phonon structure at the above-gap energies was carried out for $d^{2}V/dI^{2}(V)$ spectra of MgB$_{2}$ point contacts with a normal metal. The two-band model is assumed not only for the gap structure in $dV/dI(V)$-characteristics, but also for phonons in $d^{2}V/dI^{2}(V)$ point-contact spectra, with up to the maximum lattice vibration energy. Since the current is carried mostly by charges of 3D-band, whereas the strong electron-phonon interaction occurs in 2D-band, we observe the phonon peculiarities due to ''proximity'' effect in {\it k}-space, which depends on the variation of interband coupling through the elastic scattering.Comment: 6 pages, 4 figures, revtex4, reported in International Conference "Modern Problems in Superconductivity", 9-13 September, Yalta, Ukrain