5,343 research outputs found
Entangled Histories
We introduce quantum history states and their mathematical framework, thereby
reinterpreting and extending the consistent histories approach to quantum
theory. Through thought experiments, we demonstrate that our formalism allows
us to analyze a quantum version of history in which we reconstruct the past by
observations. In particular, we can pass from measurements to inferences about
"what happened" in a way that is sensible and free of paradox. Our framework
allows for a richer understanding of the temporal structure of quantum theory,
and we construct history states that embody peculiar, non-classical
correlations in time.Comment: 16 pages, 1 figure. v2: typo corrected, minor stylistic changes. v3:
minor stylistic changes, final version for publication in Nobel Symposium NS
15
Full-scale semispan tests of a business-jet wing with a natural laminar flow airfoil
A full-scale semispan model was investigated to evaluate and document the low-speed, high-lift characteristics of a business-jet class wing that utilized the HSNLF(1)-0213 airfoil section and a single-slotted flap system. Also, boundary-layer transition effects were examined, a segmented leading-edge droop for improved stall/spin resistance was studied, and two roll-controlled devices were evaluated. The wind-tunnel investigation showed that deployment of single-slotted, trailing-edge flap was effective in providing substantial increments in lift required for takeoff and landing performance. Fixed-transition studies to investigate premature tripping of the boundary layer indicated no adverse effects in lift and pitching-moment characteristics for either the cruise or landing configuration. The full-scale results also suggested the need to further optimize the leading-edge droop design that was developed in the subscale tests
Evolving Pacing Strategies for Team Pursuit Track Cycling
Team pursuit track cycling is a bicycle racing sport held on velodromes and
is part of the Summer Olympics. It involves the use of strategies to minimize
the overall time that a team of cyclists needs to complete a race. We present
an optimisation framework for team pursuit track cycling and show how to evolve
strategies using metaheuristics for this interesting real-world problem. Our
experimental results show that these heuristics lead to significantly better
strategies than state-of-art strategies that are currently used by teams of
cyclists
Superdensity Operators for Spacetime Quantum Mechanics
We introduce superdensity operators as a tool for analyzing quantum
information in spacetime. Superdensity operators encode spacetime correlation
functions in an operator framework, and support a natural generalization of
Hilbert space techniques and Dirac's transformation theory as traditionally
applied to standard density operators. Superdensity operators can be measured
experimentally, but accessing their full content requires novel procedures. We
demonstrate these statements on several examples. The superdensity formalism
suggests useful definitions of spacetime entropies and spacetime quantum
channels. For example, we show that the von Neumann entropy of a superdensity
operator is related to a quantum generalization of the Kolmogorov-Sinai
entropy, and compute this for a many-body system. We also suggest experimental
protocols for measuring spacetime entropies.Comment: 43+16 pages, 12 figures; v2: typos fixed, references adde
The Laughter Behind: Curriculum of Place, the Hypermasculine Imperative, and the Critical Education of a Southern Cop
This study examines the thoughts and ideologies that actuate the daily behaviors of Southern rural police officers as they pertain to practices consonant with social justice and equity. The research focus is the author’s own experience as a 21-year Southern rural police officer who ultimately obtained the position of chief of police while concurrently developing a firm commitment to ensuring social justice in his own practice and that of his subordinate police staff. The central question asks how a White male police officer from impoverished and politically and socially conservative ancestral roots could acquire a sincere concern for, and devotion to, social justice, and if the experience can be replicated to affect the thoughts, practices, and behaviors of other police officers. Methodologically and theoretically, the question is filtered through the lens of critical autoethnography, or the analysis of personal experience through an examination of personal stories framed by the tenets of critical social theory and encompassing some aspects of postmodernism, poststructuralism, and psychoanalysis to identify pertinent cultural, and in the instant case, subcultural, elements. The researcher’s hypothesis is that Southern rural police officers, regardless of gender, race, ethnicity, or other applicable demographic or social factors, are inordinately motivated by the hypermasculine imperative, a pathological masculinity that not only encourages, but virtually demands, that police officers maintain their sense of hypermasculine identity at all costs. In the author’s view, the research bears out this contention yet he proposes that the principles of critically engaged education and pedagogy (CEEP) can mitigate many, if not all, of the most pernicious effects of the hypermasculine imperative by promoting the adoption of a critical thinking philosophy and the development of critical social awareness among police officers through their promulgation in formal and informal training venues and through the intercession of police managers who have themselves adopted a philosophy of seeing police work as a serious commitment to social justice
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