Chaotic Electron Motion in Superlattices. Quantum-Classical Correspondence of the Structure of Eigenstates and LDOS

We investigate the classical-quantum correspondence for particle motion in a superlattice in the form of a 2D channel with periodic modulated boundaries. Its classical dynamics undergoes the generic transition to chaos of Hamiltonian systems as the amplitude of the modulation is increased. We show that for strong chaotic motion, the classical counterpart of the structure of eigenstates (SES) in energy space reveals an excellent agreement with the quantum one. This correspondence allows us to understand important features of the SES in terms of classical trajectories. We also show that for typical 2D modulated waveguides there exist, at any energy range, extremely localized eigenstates (in energy) which are practically unperturbed by the modulation. These states contribute to the strong fluctuations around the classical SES. The approach to the classical limit is discussed.Comment: 4 pages, 4 figure

Sleeping Beauty: Exploring a Neglected Solution

The strong law of large numbers and considerations concerning additional information strongly suggest that Beauty upon awakening has probability 1/3 to be in a heads-awakening but should still believe the probability that the coin landed heads in the Sunday toss to be 1/2. The problem is that she is in a heads-awakening if and only if the coin landed heads. So, how can she rationally assign different probabilities or credences to propositions she knows imply each other? This is the problem I address in this article. I suggest that ‘p whenever q and vice versa’ may be consistent with p and q having different probabilities if one of them refers to a sample space containing ordinary possible worlds and the other to a sample space containing centred possible worlds, because such spaces may fail to combine into one composite probability space and, as a consequence, ‘whenever’ may not be well defined; such is the main contribution of this article. 1The Sleeping Beauty Game2Groisman’s and Peter Lewis’s Approaches3Discussing Beauty’s Credences4The Principle of Equivalence's Failure5Making Sense of the Principle of Equivalence's Failure6Elga’s and Lewis’s Approaches7ConclusionAppendi

Race, Crime, and Institutional Design

Minorities are gravely overrepresented in every stage of the criminal process--from pedestrian and automobile stops, to searches and seizures, to arrests and convictions, to incarceration and capital punishment. While racial data can provide a snapshot of the current state of affairs, such information rarely satisfies questions of causation, and usually only sets the scene for normative theory

Two-plane balance and slip-ring design

A 3.25 cm (1.28 in.) two plane balance and eight channel slip ring assembly has been designed to measure and transmit the thrust (667-N;150-lb) and torque (135-N-m;100-lb-ft) components produced by wind tunnel model turboprops and drive motors operating at 300 Hz

Analysing the composition of the SME sector in high- and low-income regions. Some research hypotheses

Certain qualitative characteristics of the small and medium-sized enterprises (SMEs) operating within a territory might be essential to explain their macroeconomic impact. From this perspective, the current paper explores the relationship between the composition of the SME sector and the level of regional economic development. In this respect, a conceptual framework to analyse the composition of SME sectors is proposed considering two key aspects: on the one hand, different dimensions of SMEs’entrepreneurial orientation –innovation, cooperation, proactivity and quality orientation- and, on the other hand, the role of the external effects resulting from the inter-firm productive linkages within a specific area –differentiating between domestic, dependent, exporting and extravert SMEs. The relationship between these two key aspects is also considered and tested using a multinomial logit model. The empirical analysis uses data from a survey among over 650 SMEs in two Spanish provinces: Barcelona, as an example of a high-income economy, and Seville, as an example of a comparatively backward area

Gendered Differences in Adolescent Body Image: Youth Agency, Protective andRisk Factors

This research examined youth agency and the micro-meso system environments (protective and risks) as they shaped adolescents’ body image. National data from 11,531 students (Grades 5-10) in the Health Behavior in School Aged Children survey (2009-2010) and commentaries from six education/health professionals were used. As predicted by the Iowa and Chicago Schools of Self Concept, parental figure protected youth against negative body image by shielding them against school bullying. But, the protection and risks associated with youth agency and the micro-meso systems were gendered and operated differently for male and female youth. Female negative body image models were more complex in the salience of protective and risk factors than male models. These findings added to the literature on adolescent health and endorsed the need for wrap-around role modeling and protection for adolescents