Universality of Level Spacing Distributions in Classical Chaos

We suggest that random matrix theory applied to a classical action matrix can be used in classical physics to distinguish chaotic from non-chaotic behavior. We consider the 2-D stadium billiard system as well as the 2-D anharmonic and harmonic oscillator. By unfolding of the spectrum of such matrix we compute the level spacing distribution, the spectral auto-correlation and spectral rigidity. We observe Poissonian behavior in the integrable case and Wignerian behavior in the chaotic case. We present numerical evidence that the action matrix of the stadium billiard displays GOE behavior and give an explanation for it. The findings present evidence for universality of level fluctuations - known from quantum chaos - also to hold in classical physics

The power of negative feedback from an artificial agent to promote energy saving behavior

\u3cp\u3eIn this paper we analyze the role of negative feedback as provided by artificial agents. We examine the hypothesis that negative feedback offers substantial potential to enhance persuasive interventions aimed to change behavior. This hypothesis is tested based on a review of several studies using the same experimental paradigm that includes a virtual washing machine, in which users have to make choices how to program the washing machine. The studies show how the provision of positive and negative feedback influences these choices under various experimental conditions. Results show that negative feedback can be more effective than positive feedback, also independent of the presence of positive feedback. Negative feedback is in particular effective when the feedback is social instead of factual. Furthermore, the analysis suggests that the effect of negative feedback is enhanced under conditions of task similarity, which stimulate using the feedback for performance improvement. Finally, we show that negative feedback is superior to positive feedback under multiple goals conditions.\u3c/p\u3

Complete Labeling of G 2-Representations. Trace Formulae for Racah Operators

A trace formula is given that simultaneously allows to obtain the Casimir operators of G 2 and the (Racah) labeling operators for generic irreducible representations. The labeling operators are shown to arise as traces operators induced by a matrix decomposition. The eigenvalue problem is analyzed for the fundamental representations of G 2

Complete Labeling of G 2-Representations. Trace Formulae for Racah Operators

A trace formula is given that simultaneously allows to obtain the Casimir operators of G 2 and the (Racah) labeling operators for generic irreducible representations. The labeling operators are shown to arise as traces operators induced by a matrix decomposition. The eigenvalue problem is analyzed for the fundamental representations of G 2