Sistemi quantistici aperti e decoerenza

L’elaborato analizza principalmente i sistemi quantistici aperti, cioè quei sistemi che scambiano energia e informazione con l’ambiente circostante. Particolare attenzione è dedicata al fenomeno della decoerenza o perdita di coerenza quantistica a cui i sistemi aperti sono soggetti, che si manifesta a causa dell’interazione. Viene approfondito il meccanismo della misura, che consiste anch’esso in un’interazione con l’ambiente circostante. In ultima analisi, la teoria della decoerenza afferma che tutti i sistemi fisici esistenti sono di per sé quantistici e che, in particolare nel caso dei sistemi macroscopici, la ”classicità” emerge dall’interazione, poiché avviene la perdita di informazione della sovrapposizione di stati. Si può stimare la scala temporale in cui la perdita di coerenza quantistica si manifesta e si può vedere che per i sistemi macroscopici questa avviene molto velocemente. Si mostra anche che il processo è irreversibile, poiché determina un aumento di entropia. Si utilizza il fenomeno dell’entanglement quantistico per trattare le interazioni

Philosophy of quantum field theory: an introduction with interviews and comments

In this thesis, I address quantum theories and specifically quantum field theories in their interpretive aspects, with the aim of capturing some of the most controversial and challenging issues, also in relation to possible future developments of physics. To do so, I rely on and review some of the discussions carried on in philosophy of physics, highlighting methodologies and goals. This makes the thesis an introduction to these discussions. Based on these arguments, I built and conducted 7 face-to-face interviews with physics professors and an online survey (which received 88 responses from master's and PhD students and postdoctoral researchers in physics), with the aim of understanding how physicists make sense of concepts related to quantum theories and to find out what they can add to the discussion. Of the data collected, I report a qualitative analysis through three constructed themes

Color polymorphism in organic crystals

Colour polymorphism is a rare phenomenon that occurs when a compound possesses packing or conformational polymorphs of different colours. Here the authors review representative chemical systems that display colour polymorphism and explore the origins of this property

How “Familiness” Influences the Business: Cases from the Luxury Industry

In the current literature, several authors have exploredthe peculiarities of family businesses (Aronoff & Ward, 1995;Astrachan & Shanker, 2003; La Porta et al., 1999). On the otherhand, attention has been devoted on the characteristics of luxuryfirms (among others Mosca, 2008; Brioschi, 2005; Aiello &Donvito, 2006). However, to the best knowledge of the authors, noattempts have been made so far to investigate the “familiness”and the entrepreneurial orientation in family firms operating inthe luxury market. This article starts from the availableliterature on the subject, and aims to show how the strengthsarising from the fact of having an entrepreneurial family andbeing a luxury brand, are interwoven. The synergy that is thuscreated, leads to a fundamental competitive advantage, creatingloyalty and making the products highly desirable. The paperfurther investigates the relationship that exists betweensuccessful brands in the luxury market and the family componentof the company. It also shows how “familiness”1 can contributeactively to the success of a brand in the market of high-endgoods, and how it can ensure the longevity of family businessesoperating on the luxury market

Bioactive glass-ceramic scaffolds from novel 'inorganic gel casting' and sinter-crystallization

Highly porous wollastonite-diopside glass-ceramics have been successfully obtained by a new gel-casting technique. The gelation of an aqueous slurry of glass powders was not achieved according to the polymerization of an organic monomer, but as the result of alkali activation. The alkali activation of a Ca-Mg silicate glass (with a composition close to 50 mol % wollastonite50 mol % diopside, with minor amounts of Na2O and P2O5) allowed for the obtainment of well-dispersed concentrated suspensions, undergoing progressive hardening by curing at low temperature (40 degrees C), owing to the formation of a C-S-H (calcium silicate hydrate) gel. An extensive direct foaming was achieved by vigorous mechanical stirring of partially gelified suspensions, comprising also a surfactant. The open-celled structure resulting from mechanical foaming could be frozen' by the subsequent sintering treatment, at 900-1000 degrees C, causing substantial crystallization. A total porosity exceeding 80%, comprising both well-interconnected macro-pores and micro-pores on cell walls, was accompanied by an excellent compressive strength, even above 5 MPa