Trading Permutation Invariance for Communication in Multi-Party Non-Locality Distillation

Quantum theory puts forward phenomena unexplainable by classical physics - or information, for that matter. A prominent example is non-locality. Non-local correlations cannot be explained, in classical terms, by shared information but only by communication. On the other hand, the phenomenon does not allow for (potentially faster-than-light) message transmission. The fact that some non-local and non-signaling correlations are predicted by quantum theory, whereas others fail to be, asks for a criterion, as simple as possible, that characterizes which joint input-output behaviors are ``quantum'' and which are not. In the context of the derivation of such criteria, it is of central importance to understand when non-local correlations can be amplified by a non-interactive protocol, i.e., whether some types of weak non-locality can be distilled into stronger by local operations. Since it has been recognized that the searched-for criteria must inherently be multi-partite, the question of distillation, extensively studied and understood two-party scenarios, should be adressed in the multi-user setting, where much less is known. Considering the space of intrinsically n-partite correlations, we show the possibility of distilling weak non-local boxes to the algebraically maximal ones without any communication. Our protocols improve on previously known methods which still required partial communication. The price we have to pay for dropping the need for communication entirely is the assumption of permutation invariance: Any correlation that can be realized between some set of players is possible between any such set. This assumption is very natural since the laws of physics are invariant under spacial translation.Comment: 7 pages, 4 figures, for a conferenc

Distillation of Multi-Party Non-Locality With and Without Partial Communication

Non-local correlations are one of the most fascinating consequences of quantum physics from the point of view of information: Such correlations, although not allowing for signaling, are unexplainable by pre-shared information. The correlations have applications in cryptography, communication complexity, and sit at the very heart of many attempts of understanding quantum theory -- and its limits -- better in terms of classical information. In these contexts, the question is crucial whether such correlations can be distilled, i.e., whether weak correlations can be used for generating (a smaller amount of) stronger. Whereas the question has been studied quite extensively for bipartite correlations (yielding both pessimistic and optimistic results), only little is known in the multi-partite case. We show that a natural generalization of the well-known Popsecu-Rohrlich box can be distilled, by an adaptive protocol, to the algebraic maximum. We use this result further to show that a much bigger class of correlations, including all purely three-partite correlations, can be distilled from arbitrarily weak to maximal strength with partial communication, i.e., using only a subset of the channels required for the creation of the same correlation from scratch. In other words, we show that arbitrarily weak non-local correlations can have a "communication value" in the context of the generation of maximal non-locality.Comment: 5 pages, 3 figure

Overtime work, dual job holding and taxation

Traditionally, labour supply data do not include much information on hours and wages in secondary job or overtime work. In this paper, we estimate labour supply models based on survey information on hours and wages in overtime work and second job which is merged to detailed register information on income taxes, deductions, taxable income etc. We also allow for the effect of observed fixed costs in main occupation and unobserved fixed costs in second job, and a ‘stigmatization effect’ from unemployment. The estimated models follow a ‘Hausman-approach’. The results indicate that the labour supply elasticities are highly sensitive to the inclusion of information on overtime work and secondary job and to the handling of fixed costs of work. The estimated elasticities are numerically larger when explicit information on overtime and second job work is taken into account compared to traditional labour supply models without explicit information on overtime pay and second job wages. However, when the model allows for stigmatization effects and unobserved fixed costs of work in second job, the resulting elasticities reduce considerably.Labour supply; Dual job holding; Overtime work; Piecewise linear budget constraints

The ehrenfeucht conjecture: An algebra-framework for its proof

AbstractWe describe an algebraic framework including, in particular, the affine monoid of a given ring. Within this framework it is a simple matter to deduce Ehrenfeucht's Conjecture from Hilbert's Basis Theorem

Computational Modeling of the Mechanism of Urease

In order to elucidate aspects of the mechanism of the hydrolytic enzyme urease, theoretical calculations were undertaken on a model of the active site, using density functional theory. The bridging oxygen donor that has been found in the crystal structures was determined to be a hydroxide ion. The initial coordination of urea at the active site occurs most likely through the urea oxygen to the nickel ion with the lowest coordination number. This coordination can be made without much gain in energy. The calculations also showed that weak coordination of one of the urea amine nitrogen atoms to the second nickel atom is energetically feasible. Furthermore, a proposed mechanism including a tetrahedral intermediate generated by hydrolytic attack on the urea carbon by the bridging hydroxide was modeled, and the tetrahedral intermediate was found to be energetically unfavorable relative to terminal coordination of the substrate (urea)

Predictors of success at a rural juvenile offender facility

Thesis (M.A.) University of Alaska Fairbanks, 2002Although risk factors contributing to failure in treatment of young offenders have been studied extensively, little is written about what effects success. This study on the latter takes advantage of data obtained at a local treatment facility. This study uses statistical strategies to compare 7 different variables from a set of archival data with the outcome variable, which is 'success in treatment'. The seven independent variables are ethnicity, age at entry to treatment, pre-release pass (PRP), days in treatment, FAS/FAE, sexual offender, and psychiatric diagnosis. This data has been accumulated by a clinician at the facility and offered to the investigator for the purpose of this project. The first stage of the analysis was to correlate all of the 7 variables with the outcome variable (success/no success). The variables with the strongest association were selected, and then correlated with each other. Variables shown to be correlated with success were further studied using a Logistic Regression analysis. The results of the statistical analysis showed that non-minority status was the only variable to be clearly associated with success