Hund-enhanced electronic compressibility in FeSe and its correlation with Tc_c

We compute the compressibility of the conduction electrons in both bulk orthorhombic FeSe and monolayer FeSe on SrTiO$_3$ substrate, including dynamical electronic correlations within slave-spin mean-field + density-functional theory. Results show a zone of enhancement of the electronic compressibility crossing the interaction-doping phase diagram of these compounds in accord with previous simulations on iron pnictides and in general with the phenomenology of Hund's metals. Interestingly at ambient pressure FeSe is found slightly away from the zone with enhanced compressibility but moved right into it with hydrostatic pressure, while in monolayer FeSe the stronger enhancement region is realized on the electron-doped side. These findings correlate positively with the enhancement of superconductivity seen in experiments, and support the possibility that Hund's induced many-body correlations boost superconductive pairing when the system is at the frontier of the normal- to Hund's-metal crossover.Comment: 6 pages, 2 figure

Ly-alpha excess in high redshift radio galaxies: a signature of star formation

About 54% of radio galaxies at z>3 and 8% of radio galaxies at 2<z<3 show unusually strong Ly-alpha emission, compared with the general population of high redshift (z>2) radio galaxies. These Ly-alpha excess objects (LAEs) show Ly-alpha/HeII values consistent with or above standard photoionization model predictions. We show that the most successful explanation is the presence of a young stellar population which provides the extra supply of ionizing photons required to explain the Ly-alpha excess in at least the most extreme LAEs (probably in all of them). The measurement of unusually high Ly-alpha ratios in the extended gas of some high redshift radio galaxies suggests that star formation activity occurs in spatial scales of tens of kpc. We argue that, although the fraction of LAEs may be incompletely determined, both at 23, the much larger fraction of LAEs found at z>3 is a genuine redshift evolution and not due to selection effects. Therefore, our results suggest that the radio galaxy phenomenon is more often associated with a massive starburst at z>3 than at z<3.Comment: 14 pages, 5 figures, accepted for publication in MNRA

Spin bath interactions effects on the geometric phase

We calculate the geometric phase of a spin-1/2 particle coupled to an external environment comprising N spin-1/2 particle in the framework of open quantum systems. We analyze the decoherence factor and the deviation of the geometric phase under a nonunitary evolution from the one gained under an unitary one. We show the dependence upon the system's and bath's parameter and analyze the range of validity of the perturbative approximation. Finally, we discuss the implications of our results.Comment: 8 pages, 5 figures. Version to appear in Phys. Lett.

New design parameters for biparabolic beach profiles (SW Cadiz, Spain)

165 profiles of seventy-one beaches along the Gulf of Cadiz (SW, Spain) were studied to improve the formulation of the beach profile in tidal seas. Maritime climate, degree of energy exposure and size of the sand grains were taken into account to study the two sections of the biparabolic profile. The objective of the study was the determination of more accurate formulations of the design parameters for the equilibrium profile that involves tidal seas. These formulations were modelled and validated based on existing profiles to quantify the error existing between the real profile and the modelling. This comparative analysis was extended by considering the formulations proposed by other authors. The best results were obtained with the proposal presented herein

A Design Parameter for Reef Beach Profiles—A Methodology Applied to Cadiz, Spain

The southwestern coast of Spain is in a tidal zone (mesotidal) which causes the equilibrium profile to be developed in two different sections: the breakage section and the swash section. These two sections give rise to the typical bi-parabolic profile existing in tidal seas. The existence of areas with reefs/rocks which interrupt the normal development of the typical bi-parabolic profile causes different types of beach profiles. The objective of this article is designing an easy methodology for determining new formulations for the design parameters of the equilibrium profile of beaches with reefs in tidal seas. These formulations are applied on 16 profiles to quantify the error between the real profile data and the modelling results. A comparative analysis is extended to the formulations proposed by other authors, from which it is found that better results are obtained with the new formulations

THE TALMUD RULE AND THE SECUREMENT OF AGENTS? AWARDS

This paper provides a new characterization of the Talmud rule by means of a new property, called securement. This property says that any agent holding a feasible claim will get at least one nht of her claim, where n is the number of agents involved. We show that securement together with a weak version of path independence and the standard properties of self-duality and consistency characterize the Talmud rule.bankruptcy problems, Talmud rule, characterization results

Shocks and dust survival in nearby active galaxies: implications for the alignment effect

One of the most popular explanations for the so-called alignment effect in high redshift (z>0.7) radio galaxies is the scattering by dust of the hidden quasar light. As shown by De Young (1998) a problem with the dust scattering model is that the short destruction time-scale for dust grains means that they will not survive the passage of the radio jet. We investigate the survival of dust in the extended ionised gas of nearby active galaxies with jet/gas interactions. We discuss the implications on the alignment effect of high redshift (>0.7) radio galaxies. We conclude that although shocks are likely to destroy dust grains in regions of interaction, dust might survive in enough quantities to scatter light from the active nucleus and produce alignment between scattered light and the radio structures. We propose an observational test to investigate the existence of dust in shocked regions based on the sensitivity of calcium to depletion onto dust grains.Comment: 8 pages, 1 Figure, 3 tables, accepted for publication in MNRA

Methodology for the metric restoration of the historical cartography applied to Francisco Coello's cartografic series of the Royal Site of Aranjuez

Hojas Kilométricas (Kilometric Sheets). Specifically, the study focuses on those sheets referring to the city centre and surrounding area of the Royal Site of Aranjuez, a town in the south of the Province of Madrid. The aim of this study is to restore the actual size and measurements of scanned images of the Hojas Kilométricas. This would allow us, among other things, to reestablish both the format and scale of the original plans. To achieve this goal it is necessary to rectify and then georeference these images, i.e. assign them a geographic reference system. This procedure is essential in the overlaying and comparison of the Hojas Kilométricas of the Royal Site with other historical cartography as well as other sources related to the same area from different time periods. Subsequent research would allow us, for example, to reconstruct the time-evolution of the urban area, to spot new construction and to pinpoint the locations of any altered or missing buildings or architectural features. In addition, this would allow us to develop and integrate databases for GIS models applicable to the management of our cultural heritage

Compact radio sources and jet-driven AGN feedback in the early Universe: Constraints from integral-field spectroscopy

To investigate the impact of radio jets during the formation epoch of their massive host galaxies, we present an analysis of two massive, log(M_stel/ M_sun)~10.6 and 11.3, compact radio galaxies at z=3.5, TNJ0205+2242 and TNJ0121+1320. Their small radio sizes (R<= 10 kpc) are most likely a sign of youth. We compare their radio properties and gas dynamics with those in well extended radio galaxies at high redshift, which show strong evidence for powerful, jet-driven outflows of significant gas masses (M 10^9-10 M_sun). Our analysis combines rest-frame optical integral-field spectroscopy with existing radio imaging, CO emission line spectra, and rest-frame UV spectroscopy. [OIII]5007 line emission is compact in both galaxies and lies within the region defined by the radio lobes. For TNJ0205+2242, the Ly-alpha profile narrows significantly outside the jet radius, indicating the presence of a quiescent halo. TNJ0121+1320 has two components separated by ~10 kpc and a velocity offset of ~300 km s^-1. If motions are gravitational, this implies a dynamical mass of 2x10^11 M_sun for the more massive, radio-loud component. The dynamical mass, molecular gas mass measured from the CO line emission, and radio luminosity of these two compact radio galaxies imply that compact radio sources may well develop large-scale, energetic outflows as observed in extended radio galaxies, with the potential of removing significant fractions of the ISM from the host galaxy. The absence of luminous emission line gas extending beyond the radio emission in these sources agrees with the observed timescales and outflow rates in extended radio galaxies, and adds further evidence that the energetic, large-scale outflows observed in extended radio sources (Nesvadba et al. 2006) are indeed the result of influence of the radio jet.Comment: A&A accepte

CO line emission in the halo of a radio galaxy at z=2.6

We report the detection of luminous CO(3-2) line emission in the halo of the z=2.6 radio galaxy (HzRG) TXS0828+193, which has no detected counterpart at optical to mid-infrared wavelengths implying a stellar mass < few x10^9 M_sun and relatively low star-formation rates. With the IRAM PdBI we find two CO emission line components at the same position at ~80 kpc distance from the HzRG along the axis of the radio jet, with different blueshifts of few 100 km s^-1 relative to the HzRG and a total luminosity of ~2x10^10 K km s^-1 pc^2 detected at 8 sigma significance. HzRGs have significant galaxy overdensities and extended halos of metal-enriched gas often with embedded clouds or filaments of denser material, and likely trace very massive dark-matter halos. The CO emission may be associated with a gas-rich, low-mass satellite galaxy with little on-going star formation, in contrast to all previous CO detections of galaxies at similar redshifts. Alternatively, the CO may be related to a gas cloud or filament and perhaps jet-induced gas cooling in the outer halo, somewhat in analogy with extended CO emission found in low-redshift galaxy clusters.Comment: MNRAS Letters, accepte