Scale-Invariant Curvature Fluctuations from an Extended Semiclassical Gravity

We present an extension of the semiclassical Einstein equations which couples n-point correlation functions of a stochastic Einstein tensor to the n-point functions of the quantum stress-energy tensor. We apply this extension to calculate the quantum fluctuations during an inflationary period, where we take as a model a massive conformally coupled scalar field on a perturbed de Sitter space and describe how a renormalization independent, almost-scale-invariant power spectrum of the scalar metric perturbation is produced. Furthermore, we discuss how this model yields a natural basis for the calculation of non-Gaussianities of the considered metric fluctuations.Comment: 16 pages, 2 figures; final versio

Bose-Einstein condensate and Spontaneous Breaking of Conformal Symmetry on Killing Horizons

Local scalar QFT (in Weyl algebraic approach) is constructed on degenerate semi-Riemannian manifolds corresponding to Killing horizons in spacetime. Covariance properties of the $C^*$-algebra of observables with respect to the conformal group PSL(2,\bR) are studied.It is shown that, in addition to the state studied by Guido, Longo, Roberts and Verch for bifurcated Killing horizons, which is conformally invariant and KMS at Hawking temperature with respect to the Killing flow and defines a conformal net of von Neumann algebras, there is a further wide class of algebraic (coherent) states representing spontaneous breaking of PSL(2,\bR) symmetry. This class is labeled by functions in a suitable Hilbert space and their GNS representations enjoy remarkable properties. The states are non equivalent extremal KMS states at Hawking temperature with respect to the residual one-parameter subgroup of PSL(2,\bR) associated with the Killing flow. The KMS property is valid for the two local sub algebras of observables uniquely determined by covariance and invariance under the residual symmetry unitarily represented. These algebras rely on the physical region of the manifold corresponding to a Killing horizon cleaned up by removing the unphysical points at infinity (necessary to describe the whole PSL(2,\bR) action).Each of the found states can be interpreted as a different thermodynamic phase, containing Bose-Einstein condensate,for the considered quantum field. It is finally suggested that the found states could describe different black holes.Comment: 36 pages, 1 figure. Formula of condensate energy density modified. Accepted for pubblication in Journal of Mathematical Physic

Rigorous steps towards holography in asymptotically flat spacetimes

Scalar QFT on the boundary $\Im^+$ at null infinity of a general asymptotically flat 4D spacetime is constructed using the algebraic approach based on Weyl algebra associated to a BMS-invariant symplectic form. The constructed theory is invariant under a suitable unitary representation of the BMS group with manifest meaning when the fields are interpreted as suitable extensions to $\Im^+$ of massless minimally coupled fields propagating in the bulk. The analysis of the found unitary BMS representation proves that such a field on $\Im^+$ coincides with the natural wave function constructed out of the unitary BMS irreducible representation induced from the little group $\Delta$, the semidirect product between SO(2) and the two dimensional translational group. The result proposes a natural criterion to solve the long standing problem of the topology of BMS group. Indeed the found natural correspondence of quantum field theories holds only if the BMS group is equipped with the nuclear topology rejecting instead the Hilbert one. Eventually some theorems towards a holographic description on $\Im^+$ of QFT in the bulk are established at level of $C^*$ algebras of fields for strongly asymptotically predictable spacetimes. It is proved that preservation of a certain symplectic form implies the existence of an injective $*$-homomorphism from the Weyl algebra of fields of the bulk into that associated with the boundary $\Im^+$. Those results are, in particular, applied to 4D Minkowski spacetime where a nice interplay between Poincar\'e invariance in the bulk and BMS invariance on the boundary at $\Im^+$ is established at level of QFT. It arises that the $*$-homomorphism admits unitary implementation and Minkowski vacuum is mapped into the BMS invariant vacuum on $\Im^+$.Comment: 62 pages, amslatex, xy package; revised section 2 and the conclusions; corrected some typos; added some references; accepted for pubblication on Rev. Math. Phy

u-RANIA: a neutron detector based on \mu -RWELL technology

In the framework of the ATTRACT-uRANIA project, funded by the European Community, we are developing an innovative neutron imaging detector based on micro-Resistive WELL ($\mu$ -RWELL) technology. The $\mu$ -RWELL, based on the resistive detector concept, ensuring an efficient spark quenching mechanism, is a highly reliable device. It is composed by two main elements: a readout-PCB and a cathode. The amplification stage for this device is embedded in the readout board through a resistive layer realized by means of an industrial process with DLC (Diamond-Like Carbon). A thin layer of B$_4$C on the copper surface of the cathode allows the thermal neutrons detection through the release of $^7$Li and $\alpha$ particles in the active volume. This technology has been developed to be an efficient and convenient alternative to the $^3$He shortage. The goal of the project is to prove the feasibility of such a novel neutron detector by developing and testing small planar prototypes with readout boards suitably segmented with strip or pad read out, equipped with existing electronics or readout in current mode. Preliminary results from the test with different prototypes, showing a good agreement with the simulation, will be presented together with construction details of the prototypes and the future steps of the project.Comment: Prepared for the INSTR20 Conference Proceeding for JINS

Dilated Cardiomyopathy With Mid-Range Ejection Fraction at Diagnosis: Characterization and Natural History

Background Limited data are available on mid-range ejection fraction (mrEF) patients with dilated cardiomyopathy. We sought to define the characteristics, evolution, and long-term prognosis of dilated cardiomyopathy patients with mrEF at diagnosis. Methods and Results We analyzed all dilated cardiomyopathy patients consecutively evaluated in the Trieste Heart Muscle Disease Registry from 1988 to 2013. mrEF and reduced ejection fraction (rEF) were defined as baseline left ventricular (LV) ejection fraction values between 40% and 49% and <40%, respectively. All-cause mortality or heart transplantation, sudden cardiac death, or major ventricular arrhythmias were considered as outcome measures. Worsening LV ejection fraction (reduction to <40%) during follow-up was also considered to identify possible predictors of adverse remodeling. Among 812 enrolled patients, 175 (22%) presented with mrEF at presentation. At baseline, as compared with the rEF group, mrEF patients had lower rates of moderate-severe mitral regurgitation and restrictive LV filling pattern. During a median follow-up period of 120 (60-204) months, the mrEF group presented a lower rate of death/heart transplantation (9% versus 36%, P<0.001) and sudden cardiac death or major ventricular arrhythmias (4.5% versus 15%, P<0.001) than rEF patients. Moreover, 29 out of 175 mrEF patients (17%) evolved to rEF. Restrictive LV filling pattern emerged as the strongest predictor of rEF development following multivariable analysis. Conclusions mrEF identified a consistent subgroup of dilated cardiomyopathy patients diagnosed in an earlier stage with subsequent apparent better long-term evolution. However, 17% of these patients evolved into rEF despite the use of medical therapy. A baseline restrictive LV filling pattern was independently associated with subsequent evolution to rEF

The HADES RV Programme with HARPS-N at TNG XI. GJ 685 b: a warm super-Earth around an active M dwarf

Small rocky planets seem to be very abundant around low-mass M-type stars. Their actual planetary population is however not yet precisely understood. Currently several surveys aim to expand the statistics with intensive detection campaigns, both photometric and spectroscopic. We analyse 106 spectroscopic HARPS-N observations of the active M0-type star GJ 685 taken over the past five years. We combine these data with photometric measurements from different observatories to accurately model the stellar rotation and disentangle its signals from genuine Doppler planetary signals in the RV data. We run an MCMC analysis on the RV and activity indexes time series to model the planetary and stellar signals present in the data, applying Gaussian Process regression technique to deal with the stellar activity signals. We identify three periodic signals in the RV time series, with periods of 9, 24, and 18 d. Combining the analyses of the photometry of the star with the activity indexes derived from the HARPS-N spectra, we identify the 18 d and 9 d signals as activity-related, corresponding to the stellar rotation period and its first harmonic respectively. The 24 d signals shows no relations with any activity proxy, so we identify it as a genuine planetary signal. We find the best-fit model describing the Doppler signal of the newly-found planet, GJ 685\,b, corresponding to an orbital period $P_b = 24.160^{+0.061}_{-0.047}$ d and a minimum mass $M_P \sin i = 9.0^{+1.7}_{-1.8}$ M$_\oplus$. We also study a sample of 70 RV-detected M-dwarf planets, and present new statistical evidence of a difference in mass distribution between the populations of single- and multi-planet systems, which can shed new light on the formation mechanisms of low-mass planets around late-type stars.Comment: 18 pages, 13 figures, accepted for publication in A&

Elevated levels of eEF1A2 protein expression in triple negative breast cancer relate with poor prognosis

Eukaryotic elongation factor 1 alpha 2 (eEF1A2) is a translation factor selectively expressed by heart, skeletal muscle, nervous system and some specialized cells. Its ectopic expression relates with tumorigenesis in several types of human cancer. No data are available about the role of eEF1A2 in Triple Negative Breast Cancers (TNBC). This study investigated the relation between eEF1A2 protein levels and the prognosis of TNBC. A total of 84 TNBC diagnosed in the period 2002-2011 were included in the study. eEF1A2 protein level was measured in formalin-fixed paraffin-embedded tissues by immunohistochemistry in a semi-quantitative manner (sum of the percentage of positive cells x staining intensity) on a scale from 0 to 300. Cox regression assessed the association between eEF1A2 levels and disease-free survival (DFS) and breast cancer-specific survival (BCSS). Elevated values of eEF1A2 were associated with older age at diagnosis (p = 0.003), and androgen receptors positivity (p = 0.002). At univariate Cox analysis, eEF1A2 levels were not significantly associated with DFS and BCSS (p = 0.11 and p = 0.08, respectively) whereas adjusting for stage of disease, elevated levels of eEF1A2 protein resulted associated with poor prognosis (HR = 1.05, 95% CI: 1.01-1.11, p = 0.04 and HR = 1.07, 95% CI: 1.01-1.14, p = 0.03 for DFS and BCSS, respectively). This trend was confirmed analyzing negative versus positive samples by using categorized scores. Our data showed a negative prognostic role of eEF1A2 protein in TNBC, sustaining further investigations to confirm this result by wider and independent cohorts of patients

HADES RV Programme with HARPS-N at TNG. VII. Rotation and activity of M-Dwarfs from time-series high-resolution spectroscopy of chromospheric indicators

We aim to investigate the presence of signatures of magnetic cycles and rotation on a sample of 71 early M-dwarfs from the HADES RV programme using high-resolution time-series spectroscopy of the Ca II H & K and Halpha chromospheric activity indicators, the radial velocity series, the parameters of the cross correlation function and the V-band photometry. We used mainly HARPS-N spectra, acquired over four years, and add HARPS spectra from the public ESO database and ASAS photometry light-curves as support data, extending the baseline of the observations of some stars up to 12 years. We provide log(R'hk) measurements for all the stars in the sample, cycle length measurements for 13 stars, rotation periods for 33 stars and we are able to measure the semi-amplitude of the radial velocity signal induced by rotation in 16 stars. We complement our work with previous results and confirm and refine the previously reported relationships between the mean level of chromospheric emission, measured by the log(R'hk), with the rotation period, and with the measured semi-amplitude of the activity induced radial velocity signal for early M-dwarfs. We searched for a possible relation between the measured rotation periods and the lengths of the magnetic cycle, finding a weak correlation between both quantities. Using previous v sin i measurements we estimated the inclinations of the star's poles to the line of sight for all the stars in the sample, and estimate the range of masses of the planets GJ 3998 b and c (2.5 - 4.9 Mearth and 6.3 - 12.5 Mearth), GJ 625 b (2.82 Mearth), GJ 3942 b (7.1 - 10.0 Mearth) and GJ 15A b (3.1 - 3.3 Mearth), assuming their orbits are coplanar with the stellar rotation.Comment: 19 pages, 16 figures, 10 table

The GAPS Programme at TNG. LIII. New insights on the peculiar XO-2 system

Planets in binary systems are a fascinating and yet poorly understood phenomenon. Since there are only a few known large-separation systems in which both components host planets, characterizing them is a key target for planetary science. In this paper, we aim to carry out an exhaustive analysis of the interesting XO-2 system, where one component appears to be a system with only one planet, while the other has at least three planets. Over the last 9 years, we have collected 39 spectra of XO-2N and 106 spectra of XO-2S with the High Accuracy Radial velocity Planet Searcher for the Northern emisphere (HARPS-N) in the framework of the Global Architecture of Planetary Systems project, from which we derived precise radial velocity and activity indicator measurements. Additional spectroscopic data from the High Resolution Echelle Spectrometer and from the High Dispersion Spectrograph, and the older HARPS-N data presented in previous papers, have also been used to increase the total time span. We also used photometric data from TESS to search for potential transits that have not been detected yet. For our analysis, we mainly used PyORBIT, an advanced Python tool for the Bayesian analysis of RVs, activity indicators, and light curves. We found evidence for an additional long-period planet around XO-2S and characterized the activity cycle likely responsible for the long-term RV trend noticed for XO-2N. The new candidate is an example of a Jovian analog with $m\sin i \sim 3.7$ M$_J$, $a \sim 5.5$ au, and $e = 0.09$. We also analyzed the stability and detection limits to get some hints about the possible presence of additional planets. Our results show that the planetary system of XO-2S is at least one order of magnitude more massive than that of XO-2N. The implications of these findings for the interpretation of the previously known abundance difference between components are also discussed