Mott transition in one-dimensional boson-fermion mixtures

We numerically investigated Mott transitions and mixing-demixing transitions in one-dimensional boson-fermion mixtures at a commensurate filling. The mixing-demixing transition occurred in a qualitatively similar manner to the incommensurate filling case. We also found the Mott insulator phase appeared in both the mixing and the demixing states as the fermion-boson interaction or the boson-boson interaction increased. Phase diagrams were obtained in the interaction parameter space

Slowing and stopping of chemical waves in a narrowing canal

The propagation of a chemical wave in a narrow, cone-shaped glass capillary was investigated. When a chemical wave propagates from the wider end to the narrower end, it slows, stops, and then disappears. A phenomenological model that considers the surface effect of the glass is proposed, and this model reproduces the experimental trends.Comment: 8 pages, 5 figure

Parallel Dual Tabu Search for Capacitor Placement in Smart Grids

AbstractThis paper proposes parallel dual tabu search (PDTS) for capacitor placement in smart grids. The proposed method makes use of the dual code of the initial vale to make solution candidates diverse. The capacitor placement is one of important problems to maintain the nodal voltage profile in the distribution network level of smart grids. The problem formulation of capacitor placement may be expressed as a combinatorial optimization problem of capacitor banks. In this paper, a new method is proposed to improve the performance of tabu search (TS) of meta-heuristics. Although meta-heuristics are not affected by the initial value in smaller systems, they are inclined to give different solutions with different initial values in large-scale problems. In practice, it is very important to set up a good initial value for tabu search although a priori knowledge is not available in general. This paper focuses on the dual code of the initial value to create another initial value systematically. Mathematically, the dual code is orthogonal to the original one so that the solution search is carried out to keep the diversity of solution candidates from two most different directions. The effectiveness of the proposed method is demonstrated in a sample system

A Suzaku Study of Ejecta Structure and Origin of Hard X-ray Emission in the Supernova Remnant G156.2+5.7

We report an X-ray study of the evolved Galactic supernova remnant (SNR) G156.2+5.7 based on six pointing observations with Suzaku. The remnant's large extent (100\arcmin in diameter) allows us to investigate its radial structure in the northwestern and eastern directions from the apparent center. The X-ray spectra were well fit with a two-component non-equilibrium ionization model representing the swept-up interstellar medium (ISM) and the metal-rich ejecta. We found prominent central concentrations of Si, S and Fe from the ejecta component; the lighter elements of O, Ne and Mg were distributed more uniformly. The temperature of the ISM component suggests a slow shock (610-960 km s$^{-1}$), hence the remnant's age is estimated to be 7,000-15,000 yr, assuming its distance to be $\sim$1.1 kpc. G156.2+5.7 has also been thought to emit hard, non-thermal X-rays, despite being considerably older than any other such remnant. In response to a recent discovery of a background cluster of galaxies (2XMM J045637.2+522411), we carefully excluded its contribution, and reexamined the origin of the hard X-ray emission. We found that the residual hard X-ray emission is consistent with the expected level of the cosmic X-ray background. Thus, no robust evidence for the non-thermal emission was obtained from G156.2+5.7. These results are consistent with the picture of an evolved SNR.Comment: 10 pages 8 figures, accepted for PAS