Future constraints on variations of the fine structure constant from combined CMB and weak lensing measurements

We forecast the ability of future CMB and galaxy lensing surveys to constrain variations of the fine structure constant. We found that lensing data, as those expected from satellite experiments as Euclid could improve the constraint from future CMB experiments leading to a \Delta \alpha / \alpha = 8*10^{-4} accuracy. A variation of the fine structure constant \alpha is strongly degenerate with the Hubble constant H_0 and with inflationary parameters as the scalar spectral index n_s. These degeneracies may cause significant biases in the determination of cosmological parameters if a variation in \alpha as large as \sim 0.5 % is present at the epoch of recombination.Comment: 6 pages, 6 figures, improved text and few typos correcte

Constraints on cosmological parameters from future cosmic microwave background experiments

The Planck satellite experiment will soon let cosmologists to determine most of the cosmological parameters with unprecedented accuracy. In particular a strong improvement is expected in many parameters of interest, including neutrino mass, the amount of relativistic particles at recombination, the primordial Helium abundance and the injection of extra ionizing photon by dark matter self-annihilation. Here we review the constraints achievable by future experiments and discuss the implications for fundamental physics. © 2010 IOP Publishing Ltd

Future CMB cosmological constraints in a dark coupled universe

Cosmic Microwave Background satellite missions as the on-going Planck experiment are expected to provide the strongest constraints on a wide set of cosmological parameters. Those constraints, however, could be weakened when the assumption of a cosmological constant as the dark energy component is removed. Here we show that it will indeed be the case when there exists a coupling among the dark energy and the dark matter fluids. In particular, the expected errors on key parameters as the cold dark matter density and the angular diameter distance at decoupling are significantly larger when a dark coupling is introduced. We show that it will be the case also for future satellite missions as EPIC, unless CMB lensing extraction is performed.Comment: 6 pages, 6 figure

Chapter Sulla qualità geometrica del modello di rilievo

The 43rd UID conference, held in Genova, takes up the theme of ‘Dialogues’ as practice and debate on many fundamental topics in our social life, especially in these complex and not yet resolved times. The city of Genova offers the opportunity to ponder on the value of comparison and on the possibilities for the community, naturally focused on the aspects that concern us, as professors, researchers, disseminators of knowledge, or on all the possibile meanings of the discipline of representation and its dialogue with ‘others’, which we have broadly catalogued in three macro areas: History, Semiotics, Science / Technology. Therefore, “dialogue” as a profitable exchange based on a common language, without which it is impossible to comprehend and understand one another; and the graphic sign that connotes the conference is the precise transcription of this concept: the title ‘translated’ into signs, derived from the visual alphabet designed for the visual identity of the UID since 2017. There are many topics which refer to three macro sessions: - Witnessing (signs and history) - Communicating (signs and semiotics) - Experimenting (signs and sciences) Thanks to the different points of view, an exceptional resource of our disciplinary area, we want to try to outline the prevailing theoretical-operational synergies, the collaborative lines of an instrumental nature, the recent updates of the repertoires of images that attest and nourish the relations among representation, history, semiotics, sciences

Cosmological constraints on the Hu-Sawicki modified gravity scenario

In this paper we place new constraints on a f(R) modified gravity model recently proposed by Hu and Sawicki. After checking that the Hu and Sawicki model produces a viable cosmology, i.e. a matter dominated epoch followed by a late-time acceleration, we constrain some of its parameters by using recent observations from the UNION compilation of luminosity distances of Supernovae type Ia, including complementary information from Baryonic Acoustic Oscillations, Hubble expansion, and age data. We found that the data considered is unable to place significant constraints on the model parameters and we discuss the impact of a different assumption of the background model in cosmic parameters inference

Metadynamics Remedies for Topological Freezing

In this presentation we show that metadynamics, when used to simulate CPN−1, allows to address efficiently of freezing of topological charge, to reconstruct the free energy of the topological charge F(Q) and to compute the topological susceptibility as a function of the coupling and of the volume. We discuss possible extensions to QCD

Endoscopic vein harvesting Impact of learning curve on results and rehabilitation

Background: The tendency of modern surgery is towards the reduction of invasiveness. The aim of this study is to evaluate the impact of the learning curve, the reliability, the short term results and the advantages in terms of rapid rehabilitation of endoscopic vein harvesting (EVH) in a consecutive series of 20 patients operated on of aorto-coronary bypass surgery. Methods: Between February and June 2005, 20 patients between 61 e 82 years of age underwent EVH with the use of Vasoview® 5 (Guidant Corporation, Indianapolis, USA). To evaluate the impact of learning curve on the total operative time, patients were divided in 4 chronologically consecutive groups (G1, G2, G3, G4). Intraoperative characteristics and short term results were evaluated. Results: The mean velocity and the mean time of harvesting in G4 were 0,68 cm/min and 45 min. respectively, similar to the time required for a scheletonized left internal mammary artery harvesting. In the first 5 patients 2 conversions were required, one of them related to the EVH technique. No bleeding, functional impairment or infective complications are reported. Active mobilization was possible in every case in the first post-operative day. Conclusions: EVH is a reliable technique and the learning curve can be limited to the first 5 cases. The foreseeble reduction of infectious complications, the absence of pain and the immediate mobilization of the leg allow a rapid and effective rehabilitation

Future weak lensing constraints in a dark coupled universe

Coupled cosmologies can predict values for the cosmological parameters at low redshifts which may differ substantially from the parameters values within non-interacting cosmologies. Therefore, low redshift probes, as the growth of structure and the dark matter distribution via galaxy and weak lensing surveys constitute a unique tool to constrain interacting dark sector models. We focus here on weak lensing forecasts from future Euclid and LSST-like surveys combined with the ongoing Planck cosmic microwave background experiment. We find that these future data could constrain the dimensionless coupling to be smaller than a few $\times 10^{-2}$. The coupling parameter $\xi$ is strongly degenerate with the cold dark matter energy density $\Omega_{c}h^2$ and the Hubble constant $H_0$.These degeneracies may cause important biases in the cosmological parameter values if in the universe there exists an interaction among the dark matter and dark energy sectors.Comment: 8 pages, 6 figure

Constraining Fundamental Physics with Future CMB Experiments

The Planck experiment will soon provide a very accurate measurement of Cosmic Microwave Background anisotropies. This will let cosmologists determine most of the cosmological parameters with unprecedented accuracy. Future experiments will improve and complement the Planck data with better angular resolution and better polarization sensitivity. This unexplored region of the CMB power spectrum contains information on many parameters of interest, including neutrino mass, the number of relativistic particles at recombination, the primordial Helium abundance and the injection of additional ionizing photons by dark matter self-annihilation. We review the imprint of each parameter on the CMB and forecast the constraints achievable by future experiments by performing a Monte Carlo analysis on synthetic realizations of simulated data. We find that next generation satellite missions such as CMBPol could provide valuable constraints with a precision close to that expected in current and near future laboratory experiments. Finally, we discuss the implications of this intersection between cosmology and fundamental physics.Comment: 11 pages, 14 figure

Experimentation of augmented reality for the knowledge and communication of regular polyhedra

The research focuses on the design and testing of a teaching aid software, an augmented reality app called "Geotry", already the subject of previous research, which in this case is dedicated to the cataloging and display of regular polyhedra as a chapter fundamental of three-dimensional geometry in space. The contribution arises, in fact, from a perceived need in the university academic environment to understand more concretely some morphologies and properties of geometries in space, and the project tries to respond to this by planning an optimal design and verifying the results on the students. The applied method starts from a necessary historical study on the subject, and from the orderly classification of the geometric elements in question, to then continue with the development of the software based on modern digital representation techniques using a graphics engine, combined with immersive media. Below is the experimentation of mechanics and graphic-interactive expedients suitable for the communicative purpose, which are finally verified with surveys on samples whose feedback is reported at the end of the text. The research objectives can be said to have been achieved, as the developed software works correctly in the expected ways and appearance, and the data collected confirms the effective dissemination that took place, as well as a greater involvement generated, characteristic of immersive media