A domain of spacetime intervals in general relativity

Beginning from only a countable dense set of events and the causality relation, it is possible to reconstruct a globally hyperbolic spacetime in a purely order theoretic manner. The ultimate reason for this is that globally hyperbolic spacetimes belong to a category that is equivalent to a special category of domains called interval domains.Comment: 25 page

Efficient production of polar molecular Bose-Einstein condensates via an all-optical R-type atom-molecule adiabatic passage

We propose a scheme of "$R$-type" photoassociative adiabatic passage (PAP) to create polar molecular condensates from two different species of ultracold atoms. Due to the presence of a quasi-coherent population trapping state in the scheme, it is possible to associate atoms into molecules with a \textit{low-power} photoassociation (PA) laser. One remarkable advantage of our scheme is that a tunable atom-molecule coupling strength can be achieved by using a time-dependent PA field, which exhibits larger flexibility than using a tunable magnetic field. In addition, our results show that the PA intensity required in the "$R$-type" PAP could be greatly reduced compared to that in a conventional "$\Lambda$-type" one.Comment: 17 pages, 5 figures, to appear in New Journal of Physic

Compactness of the space of causal curves

We prove that the space of causal curves between compact subsets of a separable globally hyperbolic poset is itself compact in the Vietoris topology. Although this result implies the usual result in general relativity, its proof does not require the use of geometry or differentiable structure.Comment: 15 page

Structure and Correlates of the German Version of the Brief UPPS Impulsive Behavior Scales

The article proposes a shortened German version of the UPPS impulsive behavior scales. In Study 1, 149 high-school students completed the UPPS questionnaire, a Big-FIVE questionnaire, additional established self-report scales to measure conscientiousness and impulsivity, as well as tests of working memory capacity, reasoning, and clerical speed. Measurement models were applied to the full translated UPPS scales using confirmatory factor analysis. A satisfactory measurement model could be established only by removing many of the initial items. The remaining items correlated as expected with other self-report and ability measures: Substantial correlations with impulsivity and conscientiousness contrasted with zero correlations with working memory and reasoning ability. The association between impulsivity factors and perceptual speed was primarily a result of the number of solved items rather than the number of mistakes in the speed tasks. In Study 2 the reduced item set from Study 1 was administered to 246 participants to replicate the model. The fit of this model supports the construct validity of the final item set. The generally low correlations of the UPPS with cognitive variables questions interpretations of self-reported impulsivity that are overly focused on cognition. More appropriate cognitive criteria for impulsivity constructs should be established

A Concept for the Localization of Delamination Damages in CFRP

A concept for the identification and localization of delamination damages in CFRP is introduced. The general methodology is lined out and a localization method based on damage-caused modal damping variations is described. Using only scalar damping values requires a correlation of measured data to the corresponding data from a mathematical model in order to gain information on the damage location. The feasibility of the proposed concept is tested in an analytical damage simulation study on a stringer-stiffened aircraft panel. Some intermediate results are presented, including the modelization of piezoelectric elements and delamination damages, the selection of actuator and sensor positions and an analytical damage simulation. The work is part of the Advanced Aircraft Structures-Project (FFS) carried out by DLR in cooperation with DaimlerChrysler Aerospace