877 research outputs found

    Active and Passive Quantum Erasers for Neutral Kaons

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    Quantum marking and quantum erasure are discussed for the neutral kaon system. Contrary to other two-level systems, strangeness and lifetime of a neutral kaon state can be alternatively measured via an "active" or a "passive" procedure. This offers new quantum erasure possibilities. In particular, the operation of a quantum eraser in the "delayed choice" mode is clearly illustrated.Comment: 17 pages, LaTeX, 1 figure, references added, accepted by Phys. Rev.

    Is Hostility Dancing Along with Conversion and Dissociation?

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    Background.Hysterical symptoms frequently accompany a variety of neurotic and even psychotic psychiatric syndromes and illnesses. Methods.The presence and course of these symptoms was investigated in the present study in 73 psychiatric patients. The relationship of conversion symptoms and dissociative symptoms, both two broad dimensions of hysterical symptomatology, with self-reported hostility was examined in particular. Results.It was found that changes in dissociative symptoms showed highly significant correlations with the changes of externally directed hostility but no significant association with those of internally directed hostility. There was no significant association between changes in hostility and changes in conversion symptoms. Conclusions.In patients recovering from mental illnesses (acute or relapses), as the dissociative symptoms became less marked so the patients expressed less extrapunitive forms of hostility. Changes in dissociative symptoms correlate significantly with changes in total hostility, as well. Conversion symptoms, on the other hand, do not correlate significantly with changes in these scales. It is also of interest that no significant correlations have been shown between the score changes of the intropunitive subscales with either conversion or dissociative symptoms

    Structure, classifcation, and conformal symmetry, of elementary particles over non-archimedean space-time

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    It is known that no length or time measurements are possible in sub-Planckian regions of spacetime. The Volovich hypothesis postulates that the micro-geometry of spacetime may therefore be assumed to be non-archimedean. In this letter, the consequences of this hypothesis for the structure, classification, and conformal symmetry of elementary particles, when spacetime is a flat space over a non-archimedean field such as the pp-adic numbers, is explored. Both the Poincar\'e and Galilean groups are treated. The results are based on a new variant of the Mackey machine for projective unitary representations of semidirect product groups which are locally compact and second countable. Conformal spacetime is constructed over pp-adic fields and the impossibility of conformal symmetry of massive and eventually massive particles is proved

    Considerations on Super Poincare Algebras and their Extensions to Simple Superalgebras

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    We consider simple superalgebras which are a supersymmetric extension of \fspin(s,t) in the cases where the number of odd generators does not exceed 64. All of them contain a super Poincar\'e algebra as a contraction and another as a subalgebra. Because of the contraction property, some of these algebras can be interpreted as de Sitter or anti de Sitter superalgebras. However, the number of odd generators present in the contraction is not always minimal due to the different splitting properties of the spinor representations under a subalgebra. We consider the general case, with arbitrary dimension and signature, and examine in detail particular examples with physical implications in dimensions d=10d=10 and d=4d=4.Comment: 16 pages, AMS-LaTeX. Version to appear in the Reviews in Mathematical Physic

    On Conceptually Simple Algorithms for Variants of Online Bipartite Matching

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    We present a series of results regarding conceptually simple algorithms for bipartite matching in various online and related models. We first consider a deterministic adversarial model. The best approximation ratio possible for a one-pass deterministic online algorithm is 1/21/2, which is achieved by any greedy algorithm. D\"urr et al. recently presented a 22-pass algorithm called Category-Advice that achieves approximation ratio 3/53/5. We extend their algorithm to multiple passes. We prove the exact approximation ratio for the kk-pass Category-Advice algorithm for all k1k \ge 1, and show that the approximation ratio converges to the inverse of the golden ratio 2/(1+5)0.6182/(1+\sqrt{5}) \approx 0.618 as kk goes to infinity. The convergence is extremely fast --- the 55-pass Category-Advice algorithm is already within 0.01%0.01\% of the inverse of the golden ratio. We then consider a natural greedy algorithm in the online stochastic IID model---MinDegree. This algorithm is an online version of a well-known and extensively studied offline algorithm MinGreedy. We show that MinDegree cannot achieve an approximation ratio better than 11/e1-1/e, which is guaranteed by any consistent greedy algorithm in the known IID model. Finally, following the work in Besser and Poloczek, we depart from an adversarial or stochastic ordering and investigate a natural randomized algorithm (MinRanking) in the priority model. Although the priority model allows the algorithm to choose the input ordering in a general but well defined way, this natural algorithm cannot obtain the approximation of the Ranking algorithm in the ROM model

    Survey of the ULF wave Poynting vector near the Earth's magnetic equatorial plane

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/101878/1/pdfexplain.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/101878/2/jgra50591.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/101878/3/pdfexplain.tx

    On the formation of tilted flux ropes in the Earth's magnetotail observed with ARTEMIS

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95540/1/jgra21806.pd
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