Close-circuit domain quadruplets in BaTiO3_3 nanorods embedded in SrTiO3_3 film

Cylindrical BaTiO3 nanorods embedded in (100)-oriented SrTiO3 epitaxial film in a brush-like configuration are investigated in the framework of the Ginzburg-Landau-Devonshire model. It is shown that strain compatibility at BaTiO3/SrTiO3 interfaces keeps BaTiO3 nanorods in the rhombohedral phase even at room temperature. Depolarization field at the BaTiO3/SrTiO3 interfaces is reduced by an emission of the 109-degree or 71-degree domain boundaries. In case of nanorods of about 10-80 nm diameter, the ferroelectric domains are found to form a quadruplet with a robust flux-closure arrangement of the in-plane components of the spontaneous polarization. The out-of-plane components of the polarization are either balanced or oriented up or down along the nanorod axis. Switching of the out-of-plane polarization with coercive field of about $5.10^6$ V/m occurs as a collapse of a 71-degree cylindrical domain boundary formed at the curved circumference surface of the nanorod. The remnant domain quadruplet configuration is chiral, with the $C_4$ macroscopic symmetry. More complex stable domain configurations with coexisting clockwise and anticlockwise quadruplets contain interesting arrangement of strongly curved 71-degree boundaries.Comment: Erratta - corrected error in Fig.

PACS photometer calibration block analysis

The absolute stability of the PACS bolometer response over the entire mission lifetime without applying any corrections is about 0.5% (standard deviation) or about 8% peak-to-peak. This fantastic stability allows us to calibrate all scientific measurements by a fixed and time-independent response file, without using any information from the PACS internal calibration sources. However, the analysis of calibration block observations revealed clear correlations of the internal source signals with the evaporator temperature and a signal drift during the first half hour after the cooler recycling. These effects are small, but can be seen in repeated measurements of standard stars. From our analysis we established corrections for both effects which push the stability of the PACS bolometer response to about 0.2% (stdev) or 2% in the blue, 3% in the green and 5% in the red channel (peak-to-peak). After both corrections we still see a correlation of the signals with PACS FPU temperatures, possibly caused by parasitic heat influences via the Kevlar wires which connect the bolometers with the PACS Focal Plane Unit. No aging effect or degradation of the photometric system during the mission lifetime has been found.Comment: 15 pages, accepted for publication in Experimental Astronom

From Solar Proton Burning to Pionic Deuterium through the Nambu-Jona-Lasinio model of light nuclei

Within the Nambu-Jona-Lasinio model of light nuclei (the NNJL model), describing strong low-energy nuclear interactions, we compute the width of the energy level of the ground state of pionic deuterium. The theoretical value fits well the experimental data. Using the cross sections for the reactions nu_e + d -> p + p + e^- and nu_e + d -> p + n + nu_e, computed in the NNJL model, and the experimental values of the events of these reactions, detected by the SNO Collaboration, we compute the boron neutrino fluxes. The theoretical values agree well with the experimental data and the theoretical predictions within the Standard Solar Model by Bahcall. We argue the applicability of the constraints on the astrophysical factor for the solar proton burning, imposed by helioseismology, to the width of the energy level of the ground state of pionic deuterium. We show that the experimental data on the width satisfy these constraints. This testifies an indirect measurement of the recommended value of the astrophysical factor for the solar proton burning in terrestrial laboratories in terms of the width of the energy level of the ground state of pionic deuterium.Comment: 10 pages, no figures, Late

Energy level displacement of the excited nl state of pionic hydrogen

The energy level displacements of the excited nl states of pionic hydrogen and the contribution of the ns -> 1s transitions and the (pi^-p)_Coul -> 1s transitions of the pi^-p pair, coupled by the attractive Coulomb field in the S-wave state with a continuous energy spectrum, to the shift of the energy level of the ground state of pionic hydrogen, caused by strong low-energy interactions, are calculated within a quantum field theoretic, relativistic covariant and model-independent approach developed in nucl-th/0306047.Comment: 18 pages, no figures, latex, text is revised, references are adde