Three-Component Fermionic Atoms with Repulsive Interaction in Optical Lattices

We investigate three-component (colors) repulsive fermionic atoms in optical lattices using the dynamical mean field theory. Depending on the anisotropy of the repulsive interactions, either a color density-wave state or a color selective staggered state appears at half filling. In the former state, pairs of atoms with two of the three colors and atoms with the third color occupy different sites alternately. In the latter state, atoms with two of the three colors occupy different sites alternately and atoms with the third color are itinerant throughout the system. When the interactions are isotropic, both states are degenerate. We discuss the results using an effective model.Comment: 5 pages, 5 figure

Mott Transitions of Three-Component Fermionic Atoms with Repulsive Interaction in Optical Lattices

We investigate the Mott transitions of three-component (colors) repulsive fermionic atoms in optical lattices using the dynamical mean field theory. We find that for SU(3) symmetry breaking interactions the Mott transition occurs at incommensurate half filling. As a result, a characteristic Mott insulating state appears, where paired atoms with two different colors and atoms with the third color are localized at different sites. We also find another Mott state where atoms with two different colors are localized at different sites and atoms with the third color remain itinerant. We demonstrate that these exotic Mott phases can be detected by experimental double occupancy observations.Comment: 5 pages, 4 figure

Breeding ecology and seasonal abundance of the giant water bug

Males of the giant water bug Appasus (= Diplonychus) japonicus Vuillefroy (Belostomatidae: Heteroptera) carry egg masses on their back, but little is known about the relationship between seasonal abundance and breeding ecology of the species. In the present study, therefore, a field survey based on a mark-and-recapture census was carried out at three survey points within a rice paddy area (0.3 km2) where A. japonicus forms a meta-population in northern Okayama, Japan. We investigated the body size, seasonal abundance, dispersion, egg mass size (number of eggs within one egg mass), number of egg masses and the total eggs carried on the back of each male as fundamental parameters of the population and breeding. Significant differences in egg mass size, number of egg masses, and total number of eggs that males carried was found among the survey points. The present results suggested the possibility that the differences in breeding parameters of A. japonicus were influenced by differences in environmental factors among the microhabitats. These results are discussed in conjunction with previous reports on seasonal abundance and breeding systems in Belostomatidae bugs