Pionic Hydrogen at PSI

The measurement of the pion-nucleon scattering lengths constitutes a high-precision test of the methods of Chiral Pertubation Theory, which is the low-energy approach of QCD. The pion-nucleon s-wave scattering lengths are related to the strong-interaction shift and width of the s-states of the pionic hydrogen atom. Shift and width are determined from the measured energies and line widths of X-ray transitions to the 1s ground state when compared to the calculated electromagnetic values. A new experiment, set up at the Paul-Scherrer-Institut, has completed a first series of measurements.Comment: 4 pages, 2figures, conference Moriond XXXVIII, 2003(QCD and Hadronic Interactions

Application Protocols enabling Internet of Remote Things via Random Access Satellite Channels

Nowadays, Machine-to-Machine (M2M) and Internet of Things (IoT) traffic rate is increasing at a fast pace. The use of satellites is expected to play a large role in delivering such a traffic. In this work, we investigate the use of two of the most common M2M/IoT protocols stacks on a satellite Random Access (RA) channel, based on DVB-RCS2 standard. The metric under consideration is the completion time, in order to identify the protocol stack that can provide the best performance level

The Archaeological Sites: from excavation to “open-air” museum Cultural uses, preservation, environments

“History” has allowed that ruins from past epochs characterized the contemporary landscape over the following centuries. But when did they begin setting up an “archaeological site” within this environments? This contribute provides, through the analysis of some emblematic cases, an historical reading of the main events that have contributed to the modern concepts of “archaeological park” and “archaeological site”, summarized below, and to the difficult relationship among their surroundings. Starting from 1700 the monuments of antiquity became a "material witness" and not only a model of inspiration: this was the end of the practice of re-using ancient architecture as building materials. Meanwhile, scientific archaeological research replaced the clandestine excavations, providing finds to be exhibited in new museums. The exceptional discovery of Herculaneum and Pompeii gave a new role to the architectural remains: they became materials to be restored, preserved and exhibited, also towards a non-specialist audience, in a kind of “open-air” museum with didactic purposes. Since 1800 archaeological excavations were focused on urban areas, at first in sparsely built-up areas, later in central zones. In Rome with this cultural climate, it began to feel the need of designing a route among ruins and, at the same time, reconnecting the “big central archaeological area” with the historical city. However, during the same years, the practice of “isolating monuments” also began, denying the relationship with the surrounding environment. This practice remains in use during the first half of ‘900: it determined a deep fracture (still unresolved) between the modern town and new and old excavated area. Lately, a new cultural use of the ruins and the protection of them together with their context determined the birth of the legal instrument of the archaeological park, a new concept of protection that allows you to combine all the modern instances of restoration and museology

Design on Archaeological Sites between Enhancement and Conservation. The Museographic Project of the Acropolis of Mount Filerimos (Rhodes)

The current appearance of the archaeological area of Mount Filerimos, in the island of Rhodes, is the result of design by Rodolfo Petracco, made during the Italian occupation of Dodecanese. The site, formerly the acropolis of the ancient Ialysos, has many stratifications: a pre-hellenic cult is attested since IX cent. B.C., while the remains of architectural structures are dated between the VI cent. B.C. and 1930s, when the re-built church of "Our Lady" was enlarged with the monastery. Purpose of the project illustrated in this paper is to improve the physical and cultural use of the site and facilitate its conservation, through a more appropriate use of the architectural structures. The project, based mainly on historical knowledge and on the critical reading of the archaeological site, includes two different forms of museography. An "open-air" museum, designed to ensure accessibility to different categories of users, allows to visit the main archaeological remains with safety for users protecting the structures. The new access walkway to the church replaces the current and precarious path on the east foundation of the late-classic temple of Athena. Part of the design is the lapidarium set up with Early Christian and Byzantine architectural fragments. It is located close to the structures of the multilayered Church, to emphasize the connection between exposure and environmental context. The typological exhibition promotes understanding by the visitor and, at same time, the conservation of the blocks. A "traditional" archaeological museum is set up with the votive offerings to the ancient deity of the acropolis, which are preserved at the moment in the city of Rhodes. The exhibition is located in the monastic structures, strongly degraded after almost a century of abandonment. The new use of the monastery doesn’t alter its original image, respects the architectural character of the building and preserves, where is possible, its furnishings

Comparative analysis of permissioned blockchain frameworks for industrial applications

Blockchain is a technology that creates trust among non-trusting parties, without relying on any intermediary. Consequently, it has attracted the interest of companies operating in a multitude of sectors. However, due to the number of different blockchain solutions that have emerged in the last few years and their rapid changes, it is challenging for such companies to orient their technological decisions. This paper presents a comparative analysis of the key dimensions—namely, governance, maturity, support, latency, privacy, interoperability, flexibility, efficiency, resiliency, and scalability—of some of the most-used permissioned blockchain platforms. Moreover, we present the results of a performance evaluation considering the following frameworks: Hyperledger Fabric 2.2, Hyperledger Sawtooth 1.2, and ConsenSys Quorum 21.1 (with both the GoQuorum client and the Hyperledger Besu client). The platforms were tested under similar conditions, and official releases were used, such that our findings provide a reference for companies establishing their technological orientation

On the characterisation of a Bragg spectrometer with X-rays from an ECR source

Narrow X-ray lines from helium-like argon emitted from a dedicated ECR source have been used to determine the response function of a Bragg crystal spectrometer equipped with large area spherically bent silicon (111) or quartz (10$\bar{1}$) crystals. The measured spectra are compared with simulated ones created by a ray-tracing code based on the expected theoretical crystal's rocking curve and the geometry of the experimental set-up.Comment: Version acceptee (NIM

Asymptotic Quantum Many-Body Scars

We consider a quantum lattice spin model featuring exact quasiparticle towers of eigenstates with low entanglement at finite size, known as quantum many-body scars (QMBS). We show that the states in the neighboring part of the energy spectrum can be superposed to construct entire families of low-entanglement states whose energy variance decreases asymptotically to zero as the lattice size is increased. As a consequence, they have a relaxation time that diverges in the thermodynamic limit, and therefore exhibit the typical behavior of exact QMBS although they are not exact eigenstates of the Hamiltonian for any finite size. We refer to such states as \textit{asymptotic} QMBS. These states are orthogonal to any exact QMBS at any finite size, and their existence shows that the presence of an exact QMBS leaves important signatures of non-thermalness in the rest of the spectrum; therefore, QMBS-like phenomena can hide in what is typically considered the thermal part of the spectrum. We support our study using numerical simulations in the spin-1 XY model, a paradigmatic model for QMBS, and we conclude by presenting a weak perturbation of the model that destroys the exact QMBS while keeping the asymptotic QMBS.Comment: 4.5 pages + supplementary information. 4+3 figure

Kinetic formation of trimers in a spinless fermionic chain

We show the stabilization of two trimer phases in a chain of spinless fermions with a correlated hopping term. A trimer fluid forms due to a gain in trimer kinetic energy and competes with a fluid of unbound fermions. Furthermore, we observe two intermediate phases where these two fluids coexist and do not spatially separate. Depending on the way trimers are created out of the Fermi sea, hybridization can occur, in which case the onset of correlations between the two fluids is well captured by a generalized BCS ansatz. These results are finally extended to the formation of larger multimers, which highlights the peculiarities of pair and trimer formation.Comment: 5+9 pages, 5+7 figure

A Federated Channel Modeling System using Generative Neural Networks

The paper proposes a data-driven approach to air-to-ground channel estimation in a millimeter-wave wireless network on an unmanned aerial vehicle. Unlike traditional centralized learning methods that are specific to certain geographical areas and inappropriate for others, we propose a generalized model that uses Federated Learning (FL) for channel estimation and can predict the air-to-ground path loss between a low-altitude platform and a terrestrial terminal. To this end, our proposed FL-based Generative Adversarial Network (FL-GAN) is designed to function as a generative data model that can learn different types of data distributions and generate realistic patterns from the same distributions without requiring prior data analysis before the training phase. To evaluate the effectiveness of the proposed model, we evaluate its performance using Kullback-Leibler divergence (KL), and Wasserstein distance between the synthetic data distribution generated by the model and the actual data distribution. We also compare the proposed technique with other generative models, such as FL-Variational Autoencoder (FL-VAE) and stand-alone VAE and GAN models. The results of the study show that the synthetic data generated by FL-GAN has the highest similarity in distribution with the real data. This shows the effectiveness of the proposed approach in generating data-driven channel models that can be used in different region