Continuity and Uniqueness of Regularized Output Least Squares Optimal Estimators

AbstractThe continuity and uniqueness properties of optimal estimators with respect to data are considered for different regularizations. It is found that there is a weak stability for optimal estimators as set-valued mappings under a weak regularization. For stronger regularization results are obtained that give stability in stronger topologies and the finiteness of the set of optimal estimators. Finally, we give conditions that imply uniqueness of optimal estimators and Lipschitz continuity with respect to data

First report of Phytophthora capsici in the Lao PDR

Phytophthora capsici is reported for the first time in the Lao PDR. It was isolated from soil collected from the root zone of wilting red chilli (Capsicum annuum) plants in a polyhouse farm in Paksong district of Champasak province. The wilting chilli plants had typical symptoms of infection by P. capsici including root rot and necrosis of the outer cortex of the stem base. The isolate was identified using morphological and molecular markers. A pathogenicity trial demonstrated that the culture was pathogenic to a local cultivar of chilli seedlings

Polarization-Correlated Photon Pairs from a Single Quantum Dot

Polarization correlation in a linear basis, but not entanglement, is observed between the biexciton and single-exciton photons emitted by a single InAs quantum dot in a two-photon cascade. The results are well described quantitatively by a probabilistic model that includes two decay paths for a biexciton through a non-degenerate pair of one-exciton states, with the polarization of the emitted photons depending on the decay path. The results show that spin non-degeneracy due to quantum-dot asymmetry is a significant obstacle to the realization of an entangled-photon generation device.Comment: 4 pages, 4 figures, revised discussio

Density-functional embedding using a plane-wave basis

The constrained electron density method of embedding a Kohn-Sham system in a substrate system (first described by P. Cortona, Phys. Rev. B {\bf 44}, 8454 (1991) and T.A. Wesolowski and A. Warshel, J. Phys. Chem {\bf 97}, 8050 (1993)) is applied with a plane-wave basis and both local and non-local pseudopotentials. This method divides the electron density of the system into substrate and embedded electron densities, the sum of which is the electron density of the system of interest. Coupling between the substrate and embedded systems is achieved via approximate kinetic energy functionals. Bulk aluminium is examined as a test case for which there is a strong interaction between the substrate and embedded systems. A number of approximations to the kinetic-energy functional, both semi-local and non-local, are investigated. It is found that Kohn-Sham results can be well reproduced using a non-local kinetic energy functional, with the total energy accurate to better than 0.1 eV per atom and good agreement between the electron densities.Comment: 11 pages, 4 figure