Generalizations of Boxworld

Boxworld is a toy theory that can generate extremal nonlocal correlations known as PR boxes. These have been well established as an important tool to examine general nonlocal correlations, even beyond the correlations that are possible in quantum theory. We modify boxworld to include new features. The first modification affects the construction of joint systems such that the new theory allows entangled measurements as well as entangled states in contrast to the standard version of boxworld. The extension to multipartite systems and the consequences for entanglement swapping are analysed. Another modification provides continuous transitions between classical probability theory and boxworld, including the algebraic expression for the maximal CHSH violation as a function of the transition parameters.Comment: In Proceedings QPL 2011, arXiv:1210.029

Non-locality in theories without the no-restriction hypothesis

The framework of generalized probabilistic theories (GPT) is a widely-used approach for studying the physical foundations of quantum theory. The standard GPT framework assumes the no-restriction hypothesis, in which the state space of a physical theory determines the set of measurements. However, this assumption is not physically motivated. In Janotta and Lal [Phys. Rev. A 87, 052131 (2013)], it was shown how this assumption can be relaxed, and how such an approach can be used to describe new classes of probabilistic theories. This involves introducing a new, more general, definition of maximal joint state spaces, which we call the generalised maximal tensor product. Here we show that the generalised maximal tensor product recovers the standard maximal tensor product when at least one of the systems in a bipartite scenario obeys the no-restriction hypothesis. We also show that, under certain conditions, relaxing the no-restriction hypothesis for a given state space does not allow for stronger non-locality, although the generalized maximal tensor product may allow new joint states.Comment: In Proceedings QPL 2013, arXiv:1412.791

Limits on non-local correlations from the structure of the local state space

The outcomes of measurements on entangled quantum systems can be nonlocally correlated. However, while it is easy to write down toy theories allowing arbitrary nonlocal correlations, those allowed in quantum mechanics are limited. Quantum correlations cannot, for example, violate a principle known as macroscopic locality, which implies that they cannot violate Tsirelson's bound. This work shows that there is a connection between the strength of nonlocal correlations in a physical theory, and the structure of the state spaces of individual systems. This is illustrated by a family of models in which local state spaces are regular polygons, where a natural analogue of a maximally entangled state of two systems exists. We characterize the nonlocal correlations obtainable from such states. The family allows us to study the transition between classical, quantum, and super-quantum correlations, by varying only the local state space. We show that the strength of nonlocal correlations - in particular whether the maximally entangled state violates Tsirelson's bound or not - depends crucially on a simple geometric property of the local state space, known as strong self-duality. This result is seen to be a special case of a general theorem, which states that a broad class of entangled states in probabilistic theories - including, by extension, all bipartite classical and quantum states - cannot violate macroscopic locality. Finally, our results show that there exist models which are locally almost indistinguishable from quantum mechanics, but can nevertheless generate maximally nonlocal correlations.Comment: 26 pages, 4 figures. v2: Document structure changed. Main theorem has been extended. It applies to all quantum states now. v3: new abstrac

(Un-)gebrochene Handlungsmacht in deutschen Ausländerbehörden. Grenzanalyse in Erzählungen von Mitarbeiterinnen und Mitarbeitern.

Gegenstand des Beitrags ist die Ko-Konstruktion von Grenzen in Erzählungen von Arbeitserfahrungen durch Mitarbeiterinnen und Mitarbeiter deutscher Ausländerbehörden. Zunächst werden auf der Basis eines praxistheoretischen Grenzbegriffes Ausländerbehörden als Grenzräume verstanden. Anschließend an methodologische Überlegungen zum Erzählen von Arbeitserfahrungen und dem Interview als Produktionsraum spezifischer Erzählungen werden zwei kontrastierende Interviewausschnitte gegenübergestellt: Eine Erzählung ungebrochener und eine Erzählung gebrochender Handlungsmacht von Sachbearbeiterinnen in Ausländerbehörden. Schließlich wird die Grenzanalyse verdichtet. Die Grenze gestaltet sich in den Erzählungen als Komplex von Ein- und Ausschlüssen, in denen das Ringen um Definitionsgewalt die nicht totale Handlungsmacht der beruflichen Akteurinnen dokumentiert. In der Figur des (il-)legitimen Ausländers schließlich wird ein die prekäre Figur des nationalen Anderen rekonstruiert. Der Beitrag stellt erste Verdichtungen aus dem Promotionsprojekt "Grenzen. Aufenthalt als Gegenstand von Entscheidung und Beratung" (Arbeitstitel) vor

Moralisierungen als Modi der Sinngenese: Eine Diskussion zur Qualität beruflichen Wissens auf der Basis von Erzählungen über Aufenthaltsentscheidungen und -beratungen

In diesem Artikel werden Moralisierungen, die anhand beruflicher Fallerzählungen rekonstruiert wurden, als habitualisierte Werthaltungen diskutiert. Datengrundlage für die theoretischen Überlegungen sind Interviews mit Mitarbeiter*innen der deutschen Bundespolizei, Ausländerbehörden und Aufenthaltsberatungsstellen. Aus Erzählungen über die berufliche Fallarbeit konnten drei berufstypische Erzählmodi rekonstruiert werden. Die Erzählmodi verweisen auf berufliche Erfahrungen und Handlungen in Situationen, in denen Interaktionspartner*innen sich anders als erwartet bzw. erwünscht verhielten. Die drei Erzählmodi werden vor dem Hintergrund praxeologischer Konzepte als situierte, sinngenerierende Moralisierungen verstanden und stehen darin dem Konzept der Werthaltung nah. Im Anschluss an die methodologische Diskussion der Analyseergebnisse werden die Befunde der Studie im Lichte gegenstandstheoretischer Überlegungen zum Verhältnis von Organisationen, beruflichem Wissen und Moral reflektiert.In this article, I discuss moralizations as attitudes and habits of valuation. As I reconstructed the implicit knowledge in narratives about professional case work, these kind of moralizations became apparent. My data include interviews with federal police officers, administrators in immigration offices, and counselors, who give advice on residency issues. From my analysis, I identified three typical modes of narration, each in every professional group. Those modes of narration refer to the professional’s experiences and actions in situations in which clients acted differently from the way they were expected to. Based on the praxeological theory of knowledge, I discuss those modes of narrations as situated and sense making implicit knowledge and I emphasize the moralizing character of this knowledge. As such, the moralizations I found can be discussed as habits of valuations - a concept known from praxeological theory. Subsequent to the methodological discussion, I reflect on my findings in the light of organizational theory, theory of professional knowledge, and concepts of the moral

Philosophi … erraverunt (Spec. Univ. 1. 41) der Traktat De anima im Speculum universale des Radulfus Ardens

In the late twelfth century Platonic philosophy is gaining more and more importance for western thought in general, in particular for Christian theology. As part of this “Renaissance of the twelfth century” a new perspective is emerging, focusing on the reality of man and nature. In this context the Speculum uniuersale of Radulfus Ardens is an interesting example, which has, however, hardly been investigated. In his opus (containing 14 books) Radulfus Ardens constructs a virtue-ethical framework, for the first time connecting the morality of man systematically with anthropological facts and psychology. Radulfus Ardens receives the Platonic theory of soul and criticizes it in order to integrate some of its elements into his ethical concept. His main concern is a holistic perspective on man. The aim of this essay is to present an Early Scholastic concept of soul theory by comparing the Platonic theory of soul with the explanations of Radulfus Ardens in the first book of his Speculum uniuersale. Thus, I try to shed light on an important phase of the reception of Plato in medieval western thought