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

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

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

Gastric Secretion Mediated by Extravagal Neural Influences

In adult cats anesthetized with ether and immobilized with Flaxedil, the effects of electrical stimulation of cerebral loci on gastric secretion were studied. Stimulation of mesencephalic and diencephalic areas increased both the volume and acidity of samples collected hourly. Section of the spinal cord at the level of the second cervical vertebra abolished this secretion; however, subsequent stimulation in the lateral funiculus of the distal end of the severed cord elicited the response. These pilot studies present further evidence for extravagal mediation of gastric secretion

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