Why the Tsirelson Bound? Bub's Question and Fuchs' Desideratum

To answer Wheeler's question "Why the quantum?" via quantum information theory according to Bub, one must explain both why the world is quantum rather than classical and why the world is quantum rather than superquantum, i.e., "Why the Tsirelson bound?" We show that the quantum correlations and quantum states corresponding to the Bell basis states, which uniquely produce the Tsirelson bound for the Clauser-Horne-Shimony-Holt quantity, can be derived from conservation per no preferred reference frame (NPRF). A reference frame in this context is defined by a measurement configuration, just as with the light postulate of special relativity. We therefore argue that the Tsirelson bound is ultimately based on NPRF just as the postulates of special relativity. This constraint-based/principle answer to Bub's question addresses Fuchs' desideratum that we "take the structure of quantum theory and change it from this very overt mathematical speak ... into something like [special relativity]." Thus, the answer to Bub's question per Fuchs' desideratum is, "the Tsirelson bound obtains due to conservation per NPRF."Comment: Contains corrections to the published versio

Marital Dissolutions and Changes in Mental Health: Evidence from Rural Malawi

Family demographers conducting research in high-income countries have long examined the link between multiple dimensions of marital dissolutions—including discrete events and marital histories—and adverse health outcomes. Research on the relationship between marital dissolutions, marital histories, and health among older adults in sub-Saharan Africa is comparatively limited, and less empirically developed, despite marriage being a paramount cultural and life-course marker on the African continent. Using fixed-effects regressions and 2012 data from the Mature Adults Cohort of the Malawi Longitudinal Study of Families and Health (MLSFH-MAC) linked back to cohort information from 2008 and 2010 available through MLSFH, we test how changes in different dimensions of marital dissolutions are associated with changes in mental health among nearly 1200 respondents, in addition to the potential moderating effects of household savings and region of residence. For men, spending more of one’s life outside of marriage is associated with worse mental health, while more marital dissolutions are surprisingly linked to better mental health for women

Torsion Degrees of Freedom in the Regge Calculus as Dislocations on the Simplicial Lattice

Using the notion of a general conical defect, the Regge Calculus is generalized by allowing for dislocations on the simplicial lattice in addition to the usual disclinations. Since disclinations and dislocations correspond to curvature and torsion singularities, respectively, the method we propose provides a natural way of discretizing gravitational theories with torsion degrees of freedom like the Einstein-Cartan theory. A discrete version of the Einstein-Cartan action is given and field equations are derived, demanding stationarity of the action with respect to the discrete variables of the theory

Comparison of Bluegill Consumption Rates by Largemouth Bass and Sunshine Bass in Structured and Nonstructured Artificial Environments

We compared consumption rates of bluegills Lepomis macrochirus by largemouth bass Micropterus salmoides and sunshine bass (female white bass Morone chrysops × male striped bass M. saxatilis) in structured (about 50% coverage with artificial vegetation) and nonstructured 2,000-L fiberglass tanks. In the presence of structure, instantaneous bluegill mortality from consumption by largemouth bass was significantly higher than that caused by sunshine bass but was similar when structure was absent. Instantaneous bluegill mortality from consumption by wild largemouth bass was significantly higher than by pellet-trained largemouth bass in both structured and nonstructured environments. When pellet-trained sunshine bass served as the predator, bluegill instantaneous mortality rate was similar within structured and nonstructured environments. Our findings indicate that sunshine bass are not as adept as largemouth bass at consuming bluegills in the presence of structure but that, unlike largemouth bass, their consumption rates on bluegills are not affected by prior predatory experience

Star formation environments and the distribution of binary separations

We have carried out K-band speckle observations of a sample of 114 X-ray selected weak-line T Tauri stars in the nearby Scorpius-Centaurus OB association. We find that for binary T Tauri stars closely associated to the early type stars in Upper Scorpius, the youngest subgroup of the OB association, the peak in the distribution of binary separations is at 90 A.U. For binary T Tauri stars located in the direction of an older subgroup, but not closely associated to early type stars, the peak in the distribution is at 215 A.U. A Kolmogorov-Smirnov test indicates that the two binary populations do not result from the same distibution at a significance level of 98%. Apparently, the same physical conditions which facilitate the formation of massive stars also facilitate the formation of closer binaries among low-mass stars, whereas physical conditions unfavorable for the formation of massive stars lead to the formation of wider binaries among low-mass stars. The outcome of the binary formation process might be related to the internal turbulence and the angular momentum of molecular cloud cores, magnetic field, the initial temperature within a cloud, or - most likely - a combination of all of these. We conclude that the distribution of binary separations is not a universal quantity, and that the broad distribution of binary separations observed among main-sequence stars can be explained by a superposition of more peaked binary distributions resulting from various star forming environments. The overall binary frequency among pre-main-sequence stars in individual star forming regions is not necessarily higher than among main-sequence stars.Comment: 7 pages, Latex, 4 Postscript figures; also available at http://spider.ipac.caltech.edu/staff/brandner/pubs/pubs.html ; accepted for publication in ApJ Letter

Multiple Reflections and Diffuse Scattering in Bragg Scattering at Optical Lattices

We study Bragg scattering at 1D atomic lattices. Cold atoms are confined by optical dipole forces at the antinodes of a standing wave generated inside a laser-driven cavity. The atoms arrange themselves into an array of lens-shaped layers located at the antinodes of the standing wave. Light incident on this array at a well-defined angle is partially Bragg-reflected. We measure reflectivities as high as 30%. In contrast to a previous experiment devoted to the thin grating limit [S. Slama, et al., Phys. Rev. Lett. 94, 193901 (2005)] we now investigate the thick grating limit characterized by multiple reflections of the light beam between the atomic layers. In principle multiple reflections give rise to a photonic stop band, which manifests itself in the Bragg diffraction spectra as asymmetries and minima due to destructive interference between different reflection paths. We show that close to resonance however disorder favors diffuse scattering, hinders coherent multiple scattering and impedes the characteristic suppression of spontaneous emission inside a photonic band gap

Damage Detection by Template Matching of Scattered Waves

A method based on template matching is presented to detect and locate damage in buildings following severe shaking by an earthquake. The templates are constructed by finite‐element simulations of a suite of damage scenarios, with the solutions evaluated at the location (and orientation) of each sensor in the structure. The damage detection is carried out by cross‐correlating the templates with recordings acquired from earthquakes. A dense distributed network of sensors is important for detecting anomalies in the presence of ambient noise. The cross correlation of the templates with themselves provides a measure of the resolution of the damage location