Monogamy relations for relativistically causal correlations

Non-signalling conditions encode minimal requirements that any (quantum) systems put into spatial arrangements must satisfy in order to be consistent with special relativity. Recent works have argued that in scenarios involving more that two parties, conditions compatible with relativistic causality do not have to satisfy all possible non-signalling conditions but only a subset of them. Here we show that correlations satisfying only this subset of constraints have to satisfy highly non-local monogamy relations between the effects of space-like separated random variables. These monogamy relations take the form of new entropic inequalities between the various systems and we give a general method to derive them. Using these monogamy relations we refute previous suggestions for physical mechanisms that could lead to relativistically causal correlations, demonstrating that such mechanisms would lead to superluminal signalling.Comment: 14 pages, 4 figure

Toward correlation self-testing of quantum theory in the adaptive Clauser-Horne-Shimony-Holt game

Correlation self-testing of a theory addresses the question of whether we can identify the set of correlations realisable in a theory from its performance in a particular information processing task. Applied to quantum theory it aims to identify an information processing task whose optimal performance is achieved only by theories realising the same correlations as quantum theory in any causal structure. In [Phys. Rev. Lett. 125 060406 (2020)] we introduced a candidate task for this, the adaptive CHSH game. Here, we analyse the maximum probability of winning this game in different generalised probabilistic theories. We show that theories with a joint state space given by the minimal or the maximal tensor product are inferior to quantum theory, before considering other tensor products in theories whose elementary systems have various two-dimensional state spaces. For these, we find no theories that outperform quantum theory in the adaptive CHSH game and prove that it is impossible to recover the quantum performance in various cases. This is the first step towards a general solution that, if successful, will have wide-ranging consequences, in particular, enabling an experiment that could rule out all theories in which the set of realisable correlations does not coincide with the quantum set.Comment: 12+2 pages, 2 figures; v2: typos correcte

Analysing causal structures in generalised probabilistic theories

Causal structures give us a way to understand the origin of observed correlations. These were developed for classical scenarios, but quantum mechanical experiments necessitate their generalisation. Here we study causal structures in a broad range of theories, which include both quantum and classical theory as special cases. We propose a method for analysing differences between such theories based on the so-called measurement entropy. We apply this method to several causal structures, deriving new relations that separate classical, quantum and more general theories within these causal structures. The constraints we derive for the most general theories are in a sense minimal requirements of any causal explanation in these scenarios. In addition, we make several technical contributions that give insight for the entropic analysis of quantum causal structures. In particular, we prove that for any causal structure and for any generalised probabilistic theory, the set of achievable entropy vectors form a convex cone.Comment: 11+13 pages, 5 figures, v2: new examples and additional discussion added, v3 (published version): presentation improve

The Swiss City Canton: A POlitical Invention

All major Swiss cities are located north of the Alps. Their development can be understood best as part of the development of the North European cities—those of Germany, Flanders and France—and as part of the communal movement as it developed in those areas. Yet the cities that eventually became Swiss are those that accepted more of the characteristic institutions of Italian city-states than did the rest, and it is this acceptance of certain Italian practices—particularly the creation of a rural territory and thus eventually of a territorial city-state—that made those cities into city Cantons, able to take part in the formation of Switzerlan

Bedeutung und Entwicklung des Biologischen Landbaus in der Schweiz

Organic farming has rapidly grown in Switzerland in the past years. It is now well established in agriculture and accepted by consumers. However, recent developments show declining growth rates. This raises the question of the future that can be expected for organic farming in Switzerland. Future trends and potentials of organic farming in Switzerland made subject of two diploma theses in which prospects of the dairy and livestock sector and the fruit and vegetable sector were analysed. With a linear optimization model (farm level), taking into account probable future conditions, the development of supply was estimated. The future evolution of consumer demand was assessed by the means of a qualitative analysis. The analysis of supply and demand showed that there will be structural changes and that a future growth of the organic market is questionable. The problem does not mainly lie in the expected trend of consumer demand but rather in the development of the supply of organic products in Switzerland. In contrast to alternative production systems, organic farming is more labour-intensive, which results in higher per unit production costs. Due to the increasing abolishing of protective measures in the agricultural sector, product prices will continue to decrease. Therefore it is questionable if domestic demand for organic products can be fully met by local production.Agribusiness,

Non-Shannon inequalities in the entropy vector approach to causal structures

A causal structure is a relationship between observed variables that in general restricts the possible correlations between them. This relationship can be mediated by unobserved systems, modelled by random variables in the classical case or joint quantum systems in the quantum case. One way to differentiate between the correlations realisable by two different causal structures is to use entropy vectors, i.e., vectors whose components correspond to the entropies of each subset of the observed variables. To date, the starting point for deriving entropic constraints within causal structures are the so-called Shannon inequalities (positivity of entropy, conditional entropy and conditional mutual information). In the present work we investigate what happens when non-Shannon entropic inequalities are included as well. We show that in general these lead to tighter outer approximations of the set of realisable entropy vectors and hence enable a sharper distinction of different causal structures. Since non-Shannon inequalities can only be applied amongst classical variables, it might be expected that their use enables an entropic distinction between classical and quantum causal structures. However, this remains an open question. We also introduce techniques for deriving inner approximations to the allowed sets of entropy vectors for a given causal structure. These are useful for proving tightness of outer approximations or for finding interesting regions of entropy space. We illustrate these techniques in several scenarios, including the triangle causal structure.Comment: 23 pages + appendix; v2: minor changes to Section IV A; v3: paper has been significantly shortened, an expanded version of the removed review section can be found in arXiv:1709.08988; v4: version to be published, supplementary information available as ancillary file

Application and Quality Assessment of an Instantaneous Vehicle Emission Model at Fleet Level

A developed instantaneous emission model is applied to predict emission factors for small vehicle fleets for quality assessment. Extensive vehicle measurements of pre-Euro-1 gasoline, Euro-3 gasoline, and Euro-2 diesel vehicles are available. The data were used to develop individual vehicle emission models for each car. The prediction quality for each vehicle category was determined by averaging the results obtained from the individual vehicle models. The results show that the prediction quality is improved in comparison with the individual vehicles, even with a small number of vehicles in a specific category. This indicates that the errors in the individual models are mainly random and that prediction quality, when applied to fleets of cars, is exceptionally hig

Ca2+/calmodulin-dependent protein kinase: A key component in the contractile recovery from acidosis

Intracellular acidosis exerts substantial effects on the contractile performance of the heart. Soon after the onset of acidosis, contractility diminishes, largely due to a decrease in myofilament Ca2+ responsiveness. This decrease in contractility is followed by a progressive recovery that occurs despite the persistent acidosis. This recovery is the result of different mechanisms that converge to increase diastolic Ca2+ levels and Ca2+ transient amplitude. Recent experimental evidence indicates that activation of the Ca2+/calmodulin-dependent protein kinase II (CaMKII) is an essential step in the sequence of events that increases the Ca2+ transient amplitude and produces contractile recovery. CaMKII may act as an amplifier, providing compensatory pathways to offset the inhibitory effects of acidosis on many of the Ca2+ handling proteins. CaMKII-induced phosphorylation of the SERCA2a regulatory protein phospholamban (PLN) has the potential to promote an increase in sarcoplasmic reticulum (SR) Ca2+ uptake and SR Ca2+ load, and is a likely candidate to mediate the mechanical recovery from acidosis. In addition, CaMKII-dependent phosphorylation of proteins other than PLN may also contribute to this recovery.Facultad de Ciencias Médica

Ca2+/calmodulin-dependent protein kinase: A key component in the contractile recovery from acidosis

Intracellular acidosis exerts substantial effects on the contractile performance of the heart. Soon after the onset of acidosis, contractility diminishes, largely due to a decrease in myofilament Ca2+ responsiveness. This decrease in contractility is followed by a progressive recovery that occurs despite the persistent acidosis. This recovery is the result of different mechanisms that converge to increase diastolic Ca2+ levels and Ca2+ transient amplitude. Recent experimental evidence indicates that activation of the Ca2+/calmodulin-dependent protein kinase II (CaMKII) is an essential step in the sequence of events that increases the Ca2+ transient amplitude and produces contractile recovery. CaMKII may act as an amplifier, providing compensatory pathways to offset the inhibitory effects of acidosis on many of the Ca2+ handling proteins. CaMKII-induced phosphorylation of the SERCA2a regulatory protein phospholamban (PLN) has the potential to promote an increase in sarcoplasmic reticulum (SR) Ca2+ uptake and SR Ca2+ load, and is a likely candidate to mediate the mechanical recovery from acidosis. In addition, CaMKII-dependent phosphorylation of proteins other than PLN may also contribute to this recovery.Facultad de Ciencias Médica