Atomic relaxation processes near conducting and superconducting surfaces

The aim of this thesis is to investigate the interaction of neutral atoms with conducting and superconducting surfaces. Experimental advances in the magnetic confinement of ultracold atoms have shown that they can act as a powerful tool in a wide range of phenomena such as electric and magnetic field imaging and matter wave interferometry. Coherent manipulation of atoms and ever smaller magnetic traps are essential elements in the implementation of integrated quantum devices for fundamental research, quantum information processing and precision measurements. This thesis considers main influences on atoms placed within three different environments which are useful in achieving miniaturization and efficient control in atomic magnetic traps: carbon nanotubes, dielectric surfaces and superconducting thin films. The possibility of holding atoms near the outside of a carbon nanotubes will be addressed. In order to give a qualitative analysis of the atom-nanotube interaction, thermally induced spin-flips and the Casimir-Polder potential have been considered. The comparison between these two effects is presented in this thesis. It indicates that the Casimir-Polder force is the dominant loss mechanism and an estimation of the minimum trapping distance is given based on its effect. Secondly, a first-principles derivation of spatial atomic-sublevel decoherence near dielectric and metallic surfaces will be presented. The rate obtained for the decay of spatial coherence has dual implications, on one hand, it can be considered as a measure of the coherence length of the fluctuations of the electromagnetic field arising from a given substrate. On the other hand, it turns out to be relevant for quantum information encoding in double well potentials. Finally, the known spin-flip transition rate will be linked to the flux noise spectrum in superconducting thin films showing the feasibility of using cold atomic clouds in the investigation of vortex dynamics.Imperial Users onl

Tra vita contemplativa e vita attiva: il De Officiis di Cicerone e le sue radici aristoteliche

This paper examines the relationship between contemplative and active life in Cicero’s last philosophical work, the De officiis. This highly studied topic in the philosopher’s work and life embraces fundamental issues such as sapientia and prudentia, utilitas, and the characteristics of human nature, in its twofold and irreducible value, both descriptive and prescriptive.The second part of the paper explores how Cicero thought about these themes in connection with Aristotelian philosophy and, more specifically, with the ethical-political reflection of the Stagirite. In fact, Cicero’s text contains evident references, albeit with interesting repositioning and changes, to crucial questions about contemplative and active life already posed by Aristotle, above all the role and meaning of sapientia and prudentia, notions that Cicero explicitly connects, although in a thorny process of concordia discors, with the ones of σοφία and φρόνησι

Status and results from the ANTARES and KM3NeT-ARCA neutrino telescopes

ANTARES, currently the largest neutrino telescope in the Mediterranean Sea, has been operating for more than 10 years. ANTARES provides unprecedented sensitivity for neutrino source searches in the Southern Sky at TeV energies, so that valuable constraints can be set on the origin of the cosmic neutrinos discovered by the IceCube detector. ANTARES has also constrained the neutrino emission from possible Dark Matter annihilation in massive objects like the Sun or the Galactic Centre, and has measured the neutrino oscillation parameters in the atmospheric sector. Building on the ANTARES experience, KM3NeT, a new, much larger detector with improved design and technology is under construction on two sites in the Mediterranean sea. Deployed off the coast of Sicily, the ARCA telescope (Astroparticle Research with Cosmics in the Abyss) will be dedicated to the detection of high-energy astrophysical neutrinos. When completed, KM3NeTARCA detector with dimensions exceeding one kilometre cube, will reconstruct with an excellent angular resolution signatures of neutrinos of all flavors in a very clear deep-sea water environment. KM3NeT-ARCA, situated in the Northern hemisphere, will be able to observe up-going neutrinos from most of the Galactic Plane, making it possible to study the neutrino fluxes from different astrophysics sources, as well as neutrinos from Dark Matter annihilation. The latest results from ANTARES and the perspectives of the KM3NeT-ARCA detector will be presented

Os \u201cmuitos\u201d se dizem de muitos modos. Reflex\uf5es plat\uf4nicas e aristot\ue9licas sobre a natureza, as escolhas e o destino dos polloi

Este artigo pretende confrontar as reflexões de Platão e Aristóteles sobre o tema da natureza dos “muitos”, ou seja, seus comportamentos, os modos de ser e as escolhas de vida da maioria dos seres humanos. Mais em geral, pretende mover-se no interior de um “paradigma interpretativo” centrado na figura teórica do pollachos legomenon, isto é, sobre o reconhecimento de que “qualquer coisa é e é dizível de muitos modos” e que, portanto, os esquemas de leitura e de descrição do real devem ser multiplicados e mantidos abertos ao máximo.The purpose of this paper is to offer a confrontation between Plato’s and Aristotle’s reflections on the nature of the “many”, i.e., the behaviour, the ways of being, and the life choices of the majority of the human beings. Furthermore, we also intend to base our analysis in accordance with an “interpretative paradygm” having as its core the pollachos legomenon, i.e., the recognition that “anything is and can be said monifold”, what brings us to the conclusion that reading procedures and the descriptions of reality must be multiplied and kept as open as possible

Design of magnetic traps for neutral atoms with vortices in type-II superconducting micro-structures

We design magnetic traps for atoms based on the average magnetic field of vortices induced in a type-II superconducting thin film. This magnetic field is the critical ingredient of the demonstrated vortex-based atom traps, which operate without transport current. We use Bean's critical-state method to model the vortex field through mesoscopic supercurrents induced in the thin strip. The resulting inhomogeneous magnetic fields are studied in detail and compared to those generated by multiple normally-conducting wires with transport currents. Various vortex patterns can be obtained by programming different loading-field and transport current sequences. These variable magnetic fields are employed to make versatile trapping potentials.Comment: 11 pages, 14 figure

Sustainable accommodation choice in tourism and emotional intelligence connected: An exploratory study looking for evidence

Emotional intelligence (EI) is considered an advantage in everyday life, starting from the area of work relationships to intimacy, from stress tolerance to the general well-being of an individual. However, the theme and issue of sustainability in tourism have become relevant after a growing awareness regarding the risks of an excessively massified tourism industry and excessive exploitation of the domain. This study aims to find evidence of the relation between EI and sustainable accommodation in tourism. This is done considering EI as a mental function that promotes adaptability and consciousness, while also assuming an environmental perspective. A survey was conducted on a sample of 157 (36.3% males and 63.7% females) Italian emerging adults and adults, aged between 19 and 37 years (mean = 26.5; DS = 4.4). In particular, we studied the contribution of EI in the building of clusters, including some dimensions of sustainable hospitality and some of social well-being. For this reason, bivariate analyses were conducted to evaluate the relationship between the variables, and a cluster analysis was accomplished to identify the groups on the basis of the scores obtained from the questionnaires. The results suggest that a psychological function, such as EI, could illustrate a more comprehensive framework of sustainable accommodation and identify a new criterion for market segmentation

Sustainability and Hospitality in Tourism Experiences

Concepts of sustainability have been prominent in international discourse and development policy for at least 35 years. According to the Brundtland Commission: \u201cSustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs\u201d (1, p. 43). Sustainability in tourism is a continuous process of making a positive impact on the environment, economy, and society. It is a concept of visiting a place with great respect for the inhabitants of the area and their cultures, customs, and socio-economic systems. At the same time, "Tourism for All" is a concept that addresses a growing segment of travelers with a diverse range of needs and requirements. That is why becoming more inclusive is a more appropriate goal for the tourism industry than focusing just on "accessible tourism". Sustainability in tourism activities cannot be secured unless researchers and policy-makers pay attention to the different needs of tourists. In particular, such considerations include changes in access to resources when the tourist is a man or a woman, is a young or an old person, or has or does not have a disability. Social equality must logically be extended to old and new generations. Inclusion and equality are influenced not only by gender and age but also by other factors, including the local and cultural context, that affect incentives and the ability to adopt sustainable provision practices. This Special Issue intends to cover aspects related to the measurement of tourists\u2019 preferences (case studies, surveys, instruments, etc.) regarding the degree to which they accept (or prefer) experiences in tourism facilities or cultural programmes with sustainable characteristics. We aim to gather papers related to psycho-social and/or environmental sustainability with a particular focus on gender, age, and physical differences in tourists