Quantum dynamics of localized excitations in a symmetric trimer molecule

We study the time evolution of localized (local bond) excitations in a symmetric quantum trimer molecule. We relate the dynamical properties of localized excitations such as their spectral intensity and their temporal evolution (survival probability and tunneling of bosons) to their degree of overlap with quantum tunneling pair states. We report on the existence of degeneracy points in the trimer eigenvalue spectrum for specific values of parameters due to avoided crossings between tunneling pair states and additional states. The tunneling of localized excitations which overlap with these degenerate states is suppressed on all times. As a result local bond excitations may be strongly localized forever, similar to their classical counterparts.Comment: 9 pages, 12 figures. Improved version with more discussions. Some figures were replaced for better understanding. Accepted in Phys. Rev.

Edge-localized states in quantum one-dimensional lattices

In one-dimensional quantum lattice models with open boundaries, we find and study localization at the lattice edge. We show that edge-localized eigenstates can be found in both bosonic and fermionic systems, specifically, in the Bose-Hubbard model with on-site interactions and in the spinless fermion model with nearest-neighbor interactions. We characterize the localization through spectral studies via numerical diagonalization and perturbation theory, through considerations of the eigenfunctions, and through the study of explicit time evolution. We concentrate on few-particle systems, showing how more complicated edge states appear as the number of particles is increased.Comment: 9 pages, 12 figure

Homogeneous abundance analysis of dwarf, subgiant and giant FGK stars with and without giant planets

We have analyzed high-resolution and high signal-to-noise ratio optical spectra of nearby FGK stars with and without detected giant planets in order to homogeneously measure their photospheric parameters, mass, age, and the abundances of volatile (C, N, and O) and refractory (Na, Mg, Si, Ca, Ti, V, Mn, Fe, Ni, Cu, and Ba) elements. Our sample contains 309 stars from the solar neighborhood (up to the distance of 100 pc), out of which 140 are dwarfs, 29 are subgiants, and 140 are giants. The photospheric parameters are derived from the equivalent widths of Fe I and Fe II lines. Masses and ages come from the interpolation in evolutionary tracks and isochrones on the HR diagram. The abundance determination is based on the equivalent widths of selected atomic lines of the refractory elements and on the spectral synthesis of C_2, CN, C I, O I, and Na I features. We apply a set of statistical methods to analyze the abundances derived for the three subsamples. Our results show that: i) giant stars systematically exhibit underabundance in [C/Fe] and overabundance in [N/Fe] and [Na/Fe] in comparison with dwarfs, a result that is normally attributed to evolution-induced mixing processes in the envelope of evolved stars; ii) for solar analogs only, the abundance trends with the condensation temperature of the elements are correlated with age and anticorrelated with the surface gravity, which is in agreement with recent studies; iii) as in the case of [Fe/H], dwarf stars with giant planets are systematically enriched in [X/H] for all the analyzed elements, except for O and Ba (the former due to limitations of statistics), confirming previous findings in the literature that not only iron has an important relation with the planetary formation; and iv) giant planet hosts are also significantly overabundant for the same metallicity when the elements from Mg to Cu are combined together.Comment: 20 pages, 16 figures, 8 table

Detection of a variable ultra-fast outflow in the Narrow Line Seyfert 1 galaxy PG 1448+273

Relativistically blueshifted absorption features of highly ionised ions, the so-called ultra-fast outflows (UFOs), have been detected in the X-ray spectra of a number of accreting supermassive black holes. If these features truly originate from accretion disc winds accelerated to more than 10 per cent of the speed of light, their energy budget is very significant and they can contribute to or even drive galaxy-scale feedback from active galactic nuclei (AGN). However, the UFO spectral features are often weak due to high ionisation of the outflowing material, and the inference of the wind physical properties can be complicated by other spectral features in AGN such as relativistic reflection. Here we study a highly accreting Narrow Line Seyfert 1 galaxy PG 1448+273. We apply an automated, systematic routine for detecting outflows in accreting systems and achieve an unambiguous detection of a UFO in this AGN. The UFO absorption is observed in both soft and hard X-ray bands with the XMM-Newton observatory. The velocity of the outflow is (26900 +- 600) km/s (~0.09c), with an ionisation parameter of log ({\xi} / erg cm s^-1)=4.03_{-0.08}^{+0.10} and a column density above 10^23 cm^-2. At the same time, we detect weak warm absorption features in the spectrum of the object. Our systematic outflow search suggests the presence of further multi-phase wind structure, but we cannot claim a significant detection considering the present data quality. The UFO is not detected in a second, shorter observation with XMM-Newton, indicating variability in time, observed also in other similar AGN.Comment: Accepted for publication in MNRAS. 14 pages, 11 figures, 1 tabl

TRANSESOPHAGEAL RIGHT UPPER PULMONARY LOBECTOMY - IN VIVO PORCINE EXPERIMENTAL STUDY

TRANSESOPHAGEAL RIGHT UPPER PULMONARY LOBECTOMY - IN VIVO PORCINE EXPERIMENTAL STUDY João Moreira-Pinto, MD1,2,3; Aníbal Ferreira, MD1,2,4; Alice Miranda, DVM1,2; Carla Rolanda, MD, PhD1,2,4; Jorge Correia-Pinto, MD, PhD1,2,5 1Surgical Sciences Research Domain, Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal; 2ICVS/3B’s - PT Government Associate Laboratory, Braga/Guimarães, Portugal; 3Pediatric Surgery division, Centro Hospitalar do Porto, Porto, Portugal; 4Department of Gastroenterology, Hospital de Braga, Braga, Portugal; 5Pediatric Surgery division, Hospital de Braga, Braga, Portugal. Background and Study Aims Video-assisted thoracoscopic surgery (VATS) has been widespread as the better approach to carry out pulmonary lobectomy. Natural Orifice Transluminal Endoscopic Surgery (NOTES) is being assessed as an alternative to the transthoracic endoscopic surgery. We designed this study to test the feasibility of peroral transesophageal right upper pulmonary lobectomy with the assistance of a single transthoracic trocar. Material and Methods In ten anesthetized pigs (35-45 Kg), we performed right upper pulmonary lobectomy using a forward viewing single-channel gastroscope (introduced perorally) and an operative thoracoscope with a 5 mm working channel (introduced through a single-transthoracic 10 mm port) (Karl Storz). After introducing the gastroscope throughout an oroesophageal overtube into the esophagus, a 1 cm transverse esophagotomy was carried out in the upper third using an ESD-knife under thoracoscope control. Anatomic dissection of the right upper hilum was performed using flexible (gastroscope) and rigid (thoracoscope) instruments. After individual dissection, right upper pulmonary arteries, veins and correspondent bronchus were independently stapled using a 45-mm long, linear endostapler (EndoPath®, Ethicon Endo-Surgery) introduced through the oroesophageal overtube. After completing the lobe resection using an endoscopic snare with cautery, the specimen was extracted retrogradely through the mouth. The esophagotomy was stitched and tied using Endo Stitch™ (Covidien) and a long knot-pusher, which were handled through the oroesophageal overtube. Results Esophagotomy was performed safely in all animals. Dissection of the right upper lobe hilum elements (arteries, veins and bronchus) was also carried out in all animals without significant problems. Oroesophageal handling of the endostapplers for independent ligation of the hilum elements under transthoracic imaging was surprisingly feasible, reasonably easy to perform and reliable in 7 cases. In two cases ligation of the vessels was en bloc. In one case, severe hemorrhage occurred from incomplete vein ligation, although we could control it using electrocoagulation. Esophagotomy closure was feasible but its reliability was not tested in survival studies. All but one animal were kept alive until the end of the acute experiment when they were sacrificed. Conclusions Transesophageal right upper pulmonary lobectomy using single transthoracic trocar assistance is feasible and it may represent a step towards scarless pulmonary lobectomy. Additional survival studies are necessary to test the reliability of this procedure. Apresentador: João Moreira-Pinto, Médico Interno de Cirurgia Pediátrica, CHP

Comment on the Adiabatic Condition

The experimental observation of effects due to Berry's phase in quantum systems is certainly one of the most impressive demonstrations of the correctness of the superposition principle in quantum mechanics. Since Berry's original paper in 1984, the spin 1/2 coupled with rotating external magnetic field has been one of the most studied models where those phases appear. We also consider a special case of this soluble model. A detailed analysis of the coupled differential equations and comparison with exact results teach us why the usual procedure (of neglecting nondiagonal terms) is mathematically sound.Comment: 9 page

Relativistic spectroscopy of the extreme NLS1 IRAS13224-3809

The narrow line Seyfert 1 (NLS1) IRAS 13224-3809 is the most X-ray variable active galactic nucleus (AGN), exhibiting 0.3-10 keV flux changes of over an order of magnitude within an hour. We report on the results of the 1.5 Ms 2016 XMM-Newton/NuSTAR observing campaign, which revealed the presence of a 0.24c ultra-fast outflow in addition to the well-known strong relativistic reflection. We also summarise other key results of the campaign, such as the first detection of a non-linear RMS-flux relation in an accreting source, correlations between outflow absorption strength/velocity and source flux, and a disconnect between the X-ray and UV emission. Our results are consistent with a scenario where a disk wind is launched close to the black hole, imprinting absorption features into the spectrum and variability.Comment: 6 pages, 7 figures, contributed talk at "Revisiting narrow-line Seyfert 1 galaxies and their place in the Universe" (Padova, April 2018). Accepted for publication in Proceedings of Science, PoS(NLS1-2018)03