29,951 research outputs found
Many-body effects in Landau levels: Non-commutative geometry and squeezed correlated states
We discuss symmetry-driven squeezing and coherent states of few-particle
systems in magnetic fields. An operator approach using canonical
transformations and the SU(1,1) algebras is developed for considering Coulomb
correlations in the lowest Landau levels.Comment: 3 pages, 2 figures; to be reported at 17th Int. Conf. on High
Magnetic Fields in Semiconductor Physics, Wuerzburg, Germany, July 30 - Aug
4, 200
Electronic correlations and competing orders in multiorbital dimers: a cluster DMFT study
We investigate the violation of the first Hund's rule in 4 and 5
transition metal oxides that form solids of dimers. Bonding states within these
dimers reduce the magnetization of such materials. We parametrize the dimer
formation with realistic hopping parameters and find not only regimes, where
the system behaves as a Fermi liquid or as a Peierls insulator, but also
strongly correlated regions due to Hund's coupling and its competition with the
dimer formation. The electronic structure is investigated using the cluster
dynamical mean-field theory for a dimer in the two-plane Bethe lattice with two
orbitals per site and -filling, that is three electrons per dimer. It
reveals dimer-antiferromagnetic order of a high-spin (double exchange) state
and a low-spin (molecular orbital) state. At the crossover region we observe
the suppression of long-range magnetic order, fluctuation enhancement and
renormalization of electron masses. At certain interaction strengths the system
becomes an incoherent antiferromagnetic metal with well defined local moments.Comment: 11 pages, 10 figure
Division subspaces and integrable kernels
In this note we prove that the reproducing kernel of a Hilbert space
satisfying the division property has integrable form, is locally of trace
class, and the Hilbert space itself is a Hilbert space of holomorphic
functions.Comment: 11 page
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