Multiband-Driven Superfluid-Insulator Transition of Fermionic Atoms in Optical Lattices: A Dynamical Mean-Field-Theory Study

The superfluid-insulator transitions of the fermionic atoms in optical lattices are investigated by the two-site dynamical mean-field theory. It is shown that the Mott transition occurs as a result of the multiband effects. The quasiparticle weight in the superfluid state decreases significantly, as the system approaches the Mott transition point. By changing the interaction and the orbital splitting, we obtain the phase diagram at half filling. The numerical results are discussed in comparison with the effective boson model.Comment: 4 pages, 3 figures, Phys. Rev. A 77, 043624 (2008

Supersolid state in fermionic optical lattice systems

We study ultracold fermionic atoms trapped in an optical lattice with harmonic confinement by combining the real-space dynamical mean-field theory with a two-site impurity solver. By calculating the local particle density and the pair potential in the systems with different clusters, we discuss the stability of a supersolid state, where an s-wave superfluid coexists with a density-wave state of checkerboard pattern. It is clarified that a confining potential plays an essential role in stabilizing the supersolid state. The phase diagrams are obtained for several effective particle densities.Comment: 7 pages, 5 figures, Phys. Rev. A in pres

Using Abandoned Paddy Fields for Grazing in Northern Japan

The number of abandoned paddy fields is increasing in Japan, because the government has been regulating rice production. It has been recommended that the abandoned paddy fields be used for stock raising. However, there is sometimes a lack of information about the land on the abandoned paddy fields and farmers want to know the cost of fencing and the best grass species to use. This paper seeks to provide farmers with information on how to begin to use the abandoned paddy fields as pastures in hilly rural areas in Japan

Experimental and Theoretical Evaluation of the Effect of Panel Geometry on the Failure of Corrugated Board Panel

McKee’s formula is widely used to predict the compression strength (CS) of corrugated boxes and panels. It can accurately estimate the compression strength of boxes that are within a practical size range, but recently, larger and smaller corrugated boxes than before have been extensively developed. Therefore, there is a need for a CS prediction formula that works beyond the application range of McKee’s formula. Recent researches consider the failure mode as a combination of collapsing and buckling failure and remove the constraints and the assumptions associated with McKee’s formula. This makes it possible to more accurately estimate the CS of boxes that are not covered by McKee’s formula. Many CS formulae are derived logically from material mechanics, but doing so can make it difficult to account for various actual behaviors in detail up to when the box fails. Instead, by analyzing the behavior up to failure in detail, we explored relationships that could account for the CS consistently based on its behavior

Density-Wave and Antiferromagnetic States of Fermionic Atoms in Optical Lattices

We study the two-band effects on ultracold fermionic atoms in optical lattices by means of dynamical mean-field theory. We find that at half-filling the atomic-density-wave (ADW) state emerges owing to the two-band effects in the attractive interaction region, while the antiferromagnetic state appears in the repulsive interaction region. As the orbital splitting is increased, the quantum phase transitions from the ADW state to the superfluid state and from the antiferromagnetic state to the metallic state occur in respective regions. Systematically changing the orbital splitting and the interaction, we obtain the phase diagram at half-filling. The results are discussed using the effective boson model derived for the strong attractive interaction.Comment: 7 pages, 7 figure