Stable Existence of Phase IV inside Phase II under Pressure in Ce0.8_{0.8}La0.2_{0.2}B6_{6}

We investigate the pressure effect of the electrical resistivity and magnetization of Ce$_{0.8}$La$_{0.2}$B$_{6}$. The situation in which phase IV stably exists inside phase II at H=0 T could be realized by applying a pressure above $P\sim 1.1$ GPa. This originates from the fact that the stability of phase II under pressure is larger than those of phases IV and III. The results seem to be difficult to reproduce by taking the four interactions of $\Gamma_{\mathrm{5u}}$-type AFO, $O_{xy}$-type AFQ, $T_{xyz}$-type AFO, and AF exchange into account within a mean-field calculation framework.Comment: 4 pages, 5 figures, to appear in J. Phys. Soc. Jpn. 79 (2010) No.

On General Off-Shell Representations of Worldline (1D) Supersymmetry

Every finite-dimensional unitary representation of the N-extended worldline supersymmetry without central charges may be obtained by a sequence of differential transformations from a direct sum of minimal Adinkras, simple supermultiplets that are identifiable with representations of the Clifford algebra. The data specifying this procedure is a sequence of subspaces of the direct sum of Adinkras, which then opens an avenue for classification of the continuum of so constructed off-shell supermultiplets.Comment: 21 pages, 5 illustrations; references update

Pertunjukan Seni Sandur (Studi Tentang Perubahan Tradisi Pertunjukan Seni Sandur Sebagai Bagian Dari Ritual Setelah Panen Di Kabupaten Tuban)

Penelitian ini mengkaji permasalahan Perubahan tradisi pertunjukan seni sandur sebagai bagian dari ritual setelah panen yang awalnya diwariskan secara turun temurun kemudian ditinggalkan dan tidak dipertahankan oleh masyarakat pendukungnya. Sejalan dengan berubahnya tradisi tersebut, pertunjukan seni sandur sebagai bentuk pelaksanaan tradisi juga ikut mengalami Perubahan. Teori Perubahan tradisi yang dikemukakan oleh Sztompka digunakan sebagai pisau analisis untuk mengetahui bagaimana bentuk Perubahan dan penyebab Perubahan tradisi. Metode yang digunakan dalam penelitian ini meggunakan metode kualitatif deskriptif agar dapat menggambarkan berbagai macam kondisi realitas sosial dalam Perubahan tradisi pada pertunjukan seni sandur. Hasil dari penelitian ini adalah menunjukan bahwa Perubahan terjadi ketika masyarakat mengalami perkembangan pola pikir yang menganggap bahwa tradisi bukan satu-satunya kegiatan yang harus dilakukan setelah panen. Bentuk Perubahannya terjadi pada segi kualitatif yaitu Perubahan secara tidak sadar telah mengabaikan gagasan, simbol, makna dan ajaran hidup dalam tradisi tersebut. Dari segi kuantitatif merujuk pada jumlah masyarakat pendukungnya yang semakin berkurang. Sedangkan penyebab Perubahan berasal dari faktor internal yaitu munculnya kreativitas baru pemain sandur, serta dari faktor eksternal yang disebabkan oleh munculnya kesenian atau hiburan baru yang beraneka ragam. Meskipun tradisi tersebut sudah ditinggalkan, akan tetapi sebagai pertunjukan seni masih tetap dipertahankan sampai saat ini. Sejalan dengan berubahnya tradisi, pertunjukan seni sandur juga mengalami Perubahan dalam pelaksanaannya. Sandur berubah menjadi kesenian hiburan yang dapat ditukarkan dengan uang. Hal ini merupakan daya adaptif yang dilakukan para seniman untuk tetap mempertahankan keberadaan pertunjukan seni sandur

Optical conductivity of the Kondo insulator YbB_12: Gap formation and low-energy excitations

Optical reflectivity experiments have been conducted on single crystals of the Kondo insulator YbB_12 in order to obtain its optical conductivity, \sigma(\omega). Upon cooling below 70 K, a strong supression of \sigma(\omega) is seen in the far-infrared region, indicating the opening of an energy gap of ~ 25 meV. This gap development is coincident with a rapid decrease in the magnetic susceptibility, which shows that the gap opening has significant influence on magnetic properties. A narrow, asymmetric peak is observed at ~40 meV in \sigma(\omega), which is attributed to optical transitions between the Yb 4f-derived states across the gap. In addition, a broad peak is observed at ~0.25 eV. This peak is attributed to transitions between Yb 4f-derived states and p-d band, and is reminiscent of similar peaks previously observed for rare-earth hexaborides.Comment: 4 pages, 4 figure

Magnetic-Field-Induced 4f-Octupole in CeB6 Probed by Resonant X-ray Diffraction

CeB6, a typical Gamma_8-quartet system, exhibits a mysterious antiferroquadrupolar ordered phase in magnetic fields, which is considered as originating from the T_{xyz}-type magnetic octupole moment induced by the field. By resonant x-ray diffraction in magnetic fields, we have verified that the T_{xyz}-type octupole is indeed induced in the 4f-orbital of Ce with a propagation vector (1/2, 1/2, 1/2), thereby supporting the theory. We observed an asymmetric field dependence of the intensity for an electric quadrupole (E2) resonance when the field was reversed, and extracted a field dependence of the octupole by utilizing the interference with an electric dipole (E1) resonance. The result is in good agreement with that of the NMR-line splitting, which reflects the transferred hyperfine field at the Boron nucleus from the anisotropic spin distribution of Ce with an O_{xy}-type quadrupole. The field-reversal method used in the present study opens up the possibility of being widely applied to other multipole ordering systems such as NpO2, Ce_{x}La_{1-x}B_{6}, SmRu_{4}P_{12}, and so on.Comment: 5 pages, 4 figures, submitte

Evidence for short-range antiferromagnetic fluctuations in Kondo-insulating YbB12

The spin dynamics of mixed-valence YbB12 has been studied by inelastic neutron scattering on a high-quality single crystal. In the Kondo-insulating regime realized at low temperature, the spectra exhibit a spin-gap structure with two sharp, dispersive, in-gap excitations at E = 14.5 and approximately 20 meV. The lower mode is shown to be associated with short-range correlations near the antiferromagnetic wave vector q0 = (1/2, 1/2, 1/2). Its properties are in overall agreement with those expected for a "spin exciton'' branch in an indirect hybridization gap semiconductor.Comment: 4 pages, 4 figures ; submitted to Physical Review Letter