Quantum tomography for collider physics: Illustrations with lepton pair production

Quantum tomography is a method to experimentally extract all that is observable about a quantum mechanical system. We introduce quantum tomography to collider physics with the illustration of the angular distribution of lepton pairs. The tomographic method bypasses much of the field-theoretic formalism to concentrate on what can be observed with experimental data, and how to characterize the data. We provide a practical, experimentally-driven guide to model-independent analysis using density matrices at every step. Comparison with traditional methods of analyzing angular correlations of inclusive reactions finds many advantages in the tomographic method, which include manifest Lorentz covariance, direct incorporation of positivity constraints, exhaustively complete polarization information, and new invariants free from frame conventions. For example, experimental data can determine the $entanglement$ $entropy$ of the production process, which is a model-independent invariant that measures the degree of coherence of the subprocess. We give reproducible numerical examples and provide a supplemental standalone computer code that implements the procedure. We also highlight a property of $complex$ $positivity$ that guarantees in a least-squares type fit that a local minimum of a $\chi^{2}$ statistic will be a global minimum: There are no isolated local minima. This property with an automated implementation of positivity promises to mitigate issues relating to multiple minima and convention-dependence that have been problematic in previous work on angular distributions.Comment: 25 pages, 3 figure

Elementary School Students and their Knowledge about ‘Variable’

This mixed methods research design investigated the knowledge held by elementary school students in Grades 1-5 about variables. To explore this issue, 1,745 students completed paper pencil assessments and 73 students participated in think aloud interviews. This presentation will describe the results, including the misconceptions students exhibited and suggestions for remediation

Climate Action Planning and Urban Greenways: Weaving Together Sustainability, Health and Resilience

Envisioning and planning citywide greenways and supporting urban greening (green infrastructure) linked to climate action planning are surprisingly not well integrated in sustainable planning initiatives and in fact represent two separate landscape action approaches and two different scales and disciplines of focus. By not being strategically integrated, cities are missing out on many significant environmental and social co-benefits that are especially needed at this time. Consider, the planning focus for greenways (especially in the US context) over the last forty-years has generally emerged from a landscape design and park planning tradition and thus we see various inter-city/regional or suburban “pleasure way” or neo-“garden city” features typically centered on landscaped Class I bicycle and walking pathway as part of reclaiming or reinvesting in post-industrial urban spaces along waterways and railroad tracks.1 Meanwhile, on a very independent trajectory over the last two decades, green infrastructure planning – usually conceived as place-specific features to recapture storm-water or provide needed vegetative greening or other energy savings has been getting increasing attention as a retrofit method for improving urban ecological health (Beatley, 2014). Greenways are more than just one conceptual thing such as a linear parks but a connecting fabric or more appropriately the urban green infrastructure that can and should be woven in to retrofit the city and provide support where it is most needed and make the city more livable by introducing bands and groves of tree canopy, fresh air, access to nature, connection to unique ecological features, open-up view corridors, provide places for outdoor exercise; support local urban agriculture, offer flood protection; provide pedestrian-scale networks for socializing and non-motorized cross-city access; and, least appreciated of all, become places of cultural expression

Aerodynamic characteristics of forebody and nose strakes based on F-16 wind tunnel test experience. Volume 1: Summary and analysis

The YF-16 and F-16 developmental wind tunnel test program was reviewed. Geometrical descriptions, general comments, representative data, and the initial efforts toward the development of design guides for the application of strakes to future aircraft are presented

An Examination of the Effects of Prey Density, Mortality, Nutrients, and Foraging Tradeoffs on a System With Inducible Defenses: An Empirical and Theoretical Approach

To grasp the functioning and stability of ecosystems, it is important to understand species interactions. With many ecosystems becoming more imperiled from urbanization and anthropogenic influences it is important to understand ways in which species can adapt to rapid changes in their environment. Phenotypic plasticity is one such tool at nature’s disposal to initiate rapid change, where species with the same genetic makeup can have different expressed traits depending on their environment. Inducible defenses are one such form of phenotypic plasticity in which prey can express different levels and forms of defense depending on the threat of predation present in their environment. In this thesis, I work to determine the mechanisms by which P. aurelia balance the costs and benefits of producing defenses through the manipulation of predator and prey densities to encourage a better understanding of this form of phenotypic plasticity. Using an experimental framework, I show that prey density leads to a reduction in base morphology but may be linked to increased defense induction in this protist. At the top of the food chain predators are important in controlling prey density and increasing mortality of predators can reduce the constraints on prey growth leading to a cascading effect through a food chain. However, adaptable prey responses to predation can lead to counterintuitive reactions of the trophic levels to predator mortality. Furthermore, the death of predators plays a key role in the cycling of nutrients in a system. Energy flows up the trophic levels of a food chain through consumption, but recycling of dead biomass and excretion allows for some of those resources to be reclaimed by the lowest trophic level. In this thesis, I also investigate inducible defenses in a theoretical setting to better understand how adaptable traits may interact with nutrient recycling and foraging costs to influence responses to predator mortality and system stability. I found that nutrient recycling led to an increased negative response of predators to their own mortality while also providing an observable increase to predator density due to bottom-up. Overall, I further our understanding of inducible defenses in natural and theoretical settings

Hadron Helicity Violation in Exclusive Processes: Quantitative Calculations in Leading Order QCD

We study a new mechanism for hadronic helicity flip in high energy hard exclusive reactions. The mechanism proceeds in the limit of perfect chiral symmetry, namely without any need to flip a quark helicity. The fundamental feature of the new mechanism is the breaking of rotational symmetry of the hard collision by a scattering plane in processes involving independent quark scattering. We show that in the impulse approximation there is no evidence for of the helicity violating process as the energy or momentum transfer $Q^2$ is increased over the region 1 GeV^2 < Q^2 < 100 GeV^2. In the asymptotic region Q^2> 1000 GeV^2, a saddle point approximation with doubly logarithmic accuracy yields suppression by a fraction of power of Q^2. ``Chirally--odd" exclusive wave functions which carry non--zero orbital angular momentum and yet are leading order in the high energy limit, play an important role.Comment: uuencoded LaTeX file (21 pages) and PostScript figure

Lunar surface dynamics: Some general conclusions and new results from Apollo 16 and 17

Exposure ages of Apollo 17 rocks as measured by tracks and the Kr-Kr rare gas method are reported. Concordant ages of 22 - or + 1 million year (my) are obtained for the station 6 boulder sample 76315. This value is interpreted as the time when the station 6 boulder was emplaced in its present position. Reasonable agreement is also obtained by the two methods for another station 6 boulder, sample 76015. Discordant ages (respectively 5 and 28 my by the track and rare gas methods) are obtained for the station 7 boulder sample, 77135, indicating that the boulder was emplaced at least 5 my ago. The 72 my exposure age of 75035, in general agreement with previous measurements of approximately 85 my for another Camelot boulder, may well date the formation of Camelot. Rock 76015 was split and one surface exposed to the sky through a very small solid angle

Inverse scattering at fixed energy for layered media

AbstractIn this article we show that exponentially decreasing perturbations of the sound speed in a layered medium can be recovered from the scattering amplitude at fixed energy. We consider the unperturbed equation utt = c02(xn)δu in ℝ×ℝ, where n ≥ 3. The unperturbed sound speed, c0(xn), is assumed to be bounded, strictly positive, and constant outside a bounded interval on the real axis. The perturbed sound speed, c(x), satisfies ¦c.(x) - co(xn)¦ < C exp(−δ¦x¦) for some δ > 0. Our work is related to the recent results of H. Isozaki (J. Diff. Eq. 138) on the case where c0 takes the constant values c+ and c− on the positive and negative half-lines, and R. Weder on the case c0 = c+ for xn > h, c0 = ch, for 0 < xn, < h, and c0 = c− for xn < 0 (IIMAS-UNAM Preprint 70, November, 1997)