Nonclassical statistics of intracavity coupled χ(2)\chi^{(2)} waveguides: the quantum optical dimer

A model is proposed where two $\chi^{(2)}$ nonlinear waveguides are contained in a cavity suited for second-harmonic generation. The evanescent wave coupling between the waveguides is considered as weak, and the interplay between this coupling and the nonlinear interaction within the waveguides gives rise to quantum violations of the classical limit. These violations are particularly strong when two instabilities are competing, where twin-beam behavior is found as almost complete noise suppression in the difference of the fundamental intensities. Moreover, close to bistable transitions perfect twin-beam correlations are seen in the sum of the fundamental intensities, and also the self-pulsing instability as well as the transition from symmetric to asymmetric states display nonclassical twin-beam correlations of both fundamental and second-harmonic intensities. The results are based on the full quantum Langevin equations derived from the Hamiltonian and including cavity damping effects. The intensity correlations of the output fields are calculated semi-analytically using a linearized version of the Langevin equations derived through the positive-P representation. Confirmation of the analytical results are obtained by numerical simulations of the nonlinear Langevin equations derived using the truncated Wigner representation.Comment: 15 pages, 8 figures, submitted to Phys. Rev.

The Effects of Media and their Logic on Legitimacy Sources within Local Governance Networks: A Three-Case Comparative Study

__Abstract__ Although theoretical and empirical work on the democratic legitimacy of governance networks is growing, little attention has been paid to the impact of mediatisation on democracies. Media have their own logic of news-making led by the media’s rules, aims, production routines and constraints, which affect political decision-making processes. In this article, we specifically study how media and their logic affect three democratic legitimacy sources of political decision-making within governance networks: voice, due deliberation and accountability. We conducted a comparative case study of three local governance networks using a mixed method design, combining extensive qualitative case studies, interviews and a quantitative content analysis of media reports. In all three cases, media logic increased voice possibilities for citizen groups. Furthermore, it broadened the deliberation process, although this did not improve the quality of this process per se, because the media focus on drama and negativity. Finally, media logic often pushed political authorities into a reactive communication style as they had to fight against negative images in the media. Proactive communication about projects, such as public relation (PR) strategies and branding, is difficult in such a media landscape

Powerscapes

Thesis (M. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 2012.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (p. 149-151).In 2050, global oil supply will decline to 1/8 of today's. Migrating to the Post-Oil Era, over 10000's km2 of Powerscapes - the solar-collecting infrastructure - will be gradually constructed across the arid desert, for the indispensable production of solar energy to sustain Middle East's economy and global energy supply. The contingency of introducing the Powerscapes is a spatial problem. Unlike a powerplant that burns coal or oil, the scale of the Powerscapes is dramatically extensive. The inserted Powerscapes will interiorize the desert landscape and shelter the ground from the harsh direct sunlight that will be captured for power supply. Transformation in biological development, meteorological activity and geological phenomena will be inevitable, but the change that reduces the heat and evaporation rate will make its climatatic dynamics more habitable for human, animals and plants - an invaluable opportunity for the synthesis of energy production and climate conditioning. This thesis investigates the strategic programming and spatial configuration of such constructed landscape, capitalized by its new temporal characteristics, and sensitively adapting to it. Layers of material will be organized to form "Strata" of temporal conditions to be stretched across the landscape. To forge a symbiotic relationship between Solar Collection, human habitation, agricultural production and wild nature, the layers of material will delineate, push, flip, intersect, puncuate, wrap and merge, responding to programmatic needs and geographical dynamics that the natural geology and the Powerscapes together create. Such adaptive organization also permits certain geometrical and configuration logic to reiterate themselves in multiple scales, formulating a fractalic field with recursive part to whole relationships.by Chun Lun Otto Ng.M.Arch