Exact solution of the 1D Hubbard model in the atomic limit with inter-site magnetic coupling

In this paper we present for the first time the exact solution in the narrow-band limit of the 1D extended Hubbard model with nearest-neighbour spin-spin interactions described by an exchange constant J. An external magnetic field h is also taken into account. This result has been obtained in the framework of the Green's functions formalism, using the Composite Operator Method. By means of this theoretical background, we have studied some relevant features such as double occupancy, magnetization, spin-spin and charge-charge correlation functions and derived a phase diagram for both ferro (J>0) and anti-ferro (J<0) coupling in the limit of zero temperature. We also report a study on density of states, specific heat, charge and spin susceptibilities. In the limit of zero temperature, we show that the model exhibits a very rich phase diagram characterized by different magnetic orders and by the coexistence of charge and spin orderings at commensurate filling. Moreover, our analysis at finite temperature of density of states and response functions shows the presence of low-temperature charge and spin excitations near the phase boundaries.Comment: 20 pages, 32 figure

Bosonic sector of the two-dimensional Hubbard model studied within a two-pole approximation

The charge and spin dynamics of the two-dimensional Hubbard model in the paramagnetic phase is first studied by means of the two-pole approximation within the framework of the Composite Operator Method. The fully self-consistent scheme requires: no decoupling, the fulfillment of both Pauli principle and hydrodynamics constraints, the simultaneous solution of fermionic and bosonic sectors and a very rich momentum dependence of the response functions. The temperature and momentum dependencies, as well as the dependency on the Coulomb repulsion strength and the filling, of the calculated charge and spin susceptibilities and correlation functions are in very good agreement with the numerical calculations present in the literature

Transformation of a historical building into a Nearly Zero Energy Building (nZEB)

The European Commission strategic long-term vision for a prosperous, modern, competitive and climate-neutral economy by 2050 outlines main strategic blocks to maximise the benefits of energy efficiency, including zero emission buildings and to maximise the deployment of renewables and the use of electricity to fully decarbonise Europe’s energy supply. The following EU Climate Target Plan 2030 underlines, once again and even more urgently than in 2050, the strong need to build a modern, sustainable and resilient Europe, and this high objective means cleaner air, more energy security and more energy-efficient buildings. Looking at these European directives, Italy has signed the PNIEC, with whom intends to pursue an indicative target of reducing consumption by 2030 equal to 43% of primary energy and 39.7% of final energy compared to the PRIMES 2007 reference scenario. To achieve this goal, particular attention is paid to the existing buildings such as Palazzo De Simone. This historical building, built in the eighteenth century on a project by the architect Raguzzini, located in Benevento (BN), is now home to four different uses: the De Simone Theatre, the De Simone Chapel, a faculty of the University of Sannio and the Conservatory of Benevento. Starting from an extensive historical research, as well as from a series of non-destructive in-situ surveys and environmental measurements, it has been possible to create a satisfactory analysis framework. Later, the design objectives have been identified and, starting from these, design strategies and solutions have been formulated. It has been decided to act at a global level with a conservative restoration in compliance with the constraints imposed by the Superintendence, and at a specific level first on the building envelope, leaving the systems unchanged, then on the systems, leaving the envelope unchanged. Finally, crossing the results, the transformation of the historical building in a nZEB has been obtained, in compliance with the legislative constraints imposed by the national regulations

GIS and statistical analysis for landslide susceptibility mapping in the Daunia area, Italy

This study focuses on landslide susceptibility mapping in the Daunia area (Apulian Apennines, Italy) and achieves this by using a multivariate statistical method and data processing in a Geographical Information System (GIS). The Logistic Regression (hereafter LR) method was chosen to produce a susceptibility map over an area of 130 000 ha where small settlements are historically threatened by landslide phenomena. By means of LR analysis, the tendency to landslide occurrences was, therefore, assessed by relating a landslide inventory (dependent variable) to a series of causal factors (independent variables) which were managed in the GIS, while the statistical analyses were performed by means of the SPSS (Statistical Package for the Social Sciences) software. The LR analysis produced a reliable susceptibility map of the investigated area and the probability level of landslide occurrence was ranked in four classes. The overall performance achieved by the LR analysis was assessed by local comparison between the expected susceptibility and an independent dataset extrapolated from the landslide inventory. Of the samples classified as susceptible to landslide occurrences, 85% correspond to areas where landslide phenomena have actually occurred. In addition, the consideration of the regression coefficients provided by the analysis demonstrated that a major role is played by the "land cover" and "lithology" causal factors in determining the occurrence and distribution of landslide phenomena in the Apulian Apennines

Entanglement properties and phase diagram of the two orbital Hubbard model

We study the two-orbital Hubbard model in the limit of vanishing kinetic energy. The phase diagram in the V-J plane, with V and J denoting the interorbital hybridization and exchange coupling respectively, at half filling is obtained. A singlet(dimer)-triplet transition is found for a critical value of the ratio V/J. The entropy of formation, both in the mode and in the particle pictures, presents a jump at the same critical line in conformity with the suggested relation between criticality and entanglement

On the Tomographic Picture of Quantum Mechanics

We formulate necessary and sufficient conditions for a symplectic tomogram of a quantum state to determine the density state. We establish a connection between the (re)construction by means of symplectic tomograms with the construction by means of Naimark positive-definite functions on the Weyl-Heisenberg group. This connection is used to formulate properties which guarantee that tomographic probabilities describe quantum states in the probability representation of quantum mechanics.Comment: 10 pages,latex,submitted to Physics Letters

VST - VLT Survey Telescope Integration Status

The VLT Survey Telescope (VST) is a 2.6m aperture, wide field, UV to I facility, to be installed at the European Southern Observatory (ESO) on the Cerro Paranal Chile. VST was primarily intended to complement the observing capabilities of VLT with wide-angle imaging for detecting and pre-characterising sources for further observations with the VLT.Comment: 2 pages, 2 figures, conferenc

Energy and Environmental Refurbishment of the Hygiene Institute within the Sapienza University of Rome campus

Starting from the definition of sustainable development introduced by the 2030 Agenda, and the most recent European implementation tools such as above all the New Green Deal, three goals have been highlighted as pilot objectives of this research: Goal 13 “Climate Action” to strengthen the resilience and adaptability of our building stock to climate-related risks, Goal 7 “Affordable and Clean Energy” by increasing the share of renewable energy and improving the energy efficiency of the existing building stock and Goal 6 “Clean Water and Sanitation”, aimed, in this specific case, at a sustainable management of water resources and technologies for recycling and reuse. In particular, the research work focused on the energy and environmental redevelopment, from a green perspective, of the “Sanarelli” Institute of Hygiene within the “Sapienza” University of Rome campus. The building was built in 1935 and, following a series of changes over the years, currently has a total volume of 37,700 m3 and an area of 9,475 m2. After an in-depth study of the status quo thanks to inspections, surveys, non- invasive investigations and environmental analyses, the work has focused on the definition of specific objectives with the ultimate aim of the energy and environmental refurbishment intervention by tracing 7 strategies thanks to which it has been possible to identify 9 technical solutions to be applied to the Institute. The design choices highlight a close synergy between active and passive devices which together contribute to achieving a circular use of water resources on site, with systems for capturing and collecting rainwater and treating wastewater, as well as achieving a significant improvement in the energy behaviour of the building. This improvement has been possible not only thanks to the updating, with respect to nowadays uses and standards, of the characteristics of the building envelope and of the active systems, but also thanks to the close collaboration between the active and passive technological solutions that have led to satisfactory results with a view to reducing CO2 emissions

Spin and charge orderings in the atomic limit of the U-V-J model

In this paper we study a generalization of the 1D Hubbard model by considering density-density and Ising-type spin-spin nearest neighbor (NN) interactions, parameterized by $V$ and $J$, respectively. We present the T=0 phase diagram for both ferro ($J>0$) and anti-ferro ($J<0$) coupling obtained in the narrow-band limit by means of an extension to zero-temperature of the transfer-matrix method. Based on the values of the Hamiltonian parameters, we identify a number of phases that involve orderings of the double occupancy, NN density and spin correlations, being these latter very fragile.Comment: 4 pages, 2 figures, SCES2011 Proceeding