8,110 research outputs found
A class of Heisenberg models with the orthogonal dimer ground states
Extensions of the Shastry-Sutherland model are possible in various ways. In
particular, it is possible to construct a natural model in three dimensions
which has the exact dimer ground state. Recently found spin gap system
SrCu_2(BO_3)_2 has this structure. The exchange constants between the layers is
expected to be smaller than the intra-layer couplings. However, the exactness
of the dimer state for the three dimensional structure is important to
understand why magnetic properties of SrCu_2(BO_3)_2 are described well by the
two dimensional model.Comment: 3 pages, 5 figures, to appear in Journal of Physics: Condensed Matte
Construction of KbarN potential and structure of Lambda(1405) based on chiral unitary approach
Based on chiral unitary approach, we construct the realistic KbarN local
potential, which is useful for the quantitative calculation of Kbar-nuclei.
Since the resonance pole structure of the KbarN system seems important for the
Kbar-nuclei and the spacial structure of Lambda(1405), we establish the
construction procedure of the local potential paying attention to the
scattering amplitude in the complex energy plane. Furthermore, for the
quantitative study of the Kbar-nuclei, we consider the constraint from the
recent experimental data measured by SIDDHARTA, which significantly reduces the
uncertainty of the KbarN amplitude. With this new local potential, we estimate
the spacial structure of Lambda(1405) and obtain the result indicating the
meson-baryon molecular state of Lambda(1405).Comment: 5 pages, 2 figure
Cohen-Macaulay modules and holonomic modules over filtered rings
We study Gorenstein dimension and grade of a module over a filtered ring
whose assosiated graded ring is a commutative Noetherian ring. An equality or
an inequality between these invariants of a filtered module and its associated
graded module is the most valuable property for an investigation of filtered
rings. We prove an inequality G-dim and an equality , whenever Gorenstein dimension of is
finite (Theorems 2.3 and 2.8). We would say that the use of G-dimension adds a
new viewpoint for studying filtered rings and modules. We apply these results
to a filtered ring with a Cohen-Macaulay or Gorenstein associated graded ring
and study a Cohen-Macaulay, perfect or holonomic module.Comment: 21 pages, to appear in Communications in Algebr
Cross-Jurisdictional Relationships in Local Public Health: Preliminary Summary of an Environmental Scan
Outlines issues involved in formal collaborative relationships between local health departments to enhance services across communities, including how stakeholders define them, structure, rationale, effectiveness, success and risk factors, and barriers
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