Self-Consistent Projection Operator Theory in Nonlinear Quantum Optical Systems: A case study on Degenerate Optical Parametric Oscillators

Nonlinear quantum optical systems are of paramount relevance for modern quantum technologies, as well as for the study of dissipative phase transitions. Their nonlinear nature makes their theoretical study very challenging and hence they have always served as great motivation to develop new techniques for the analysis of open quantum systems. In this article we apply the recently developed self-consistent projection operator theory to the degenerate optical parametric oscillator to exemplify its general applicability to quantum optical systems. We show that this theory provides an efficient method to calculate the full quantum state of each mode with high degree of accuracy, even at the critical point. It is equally successful in describing both the stationary limit and the dynamics, including regions of the parameter space where the numerical integration of the full problem is significantly less efficient. We further develop a Gaussian approach consistent with our theory, which yields sensibly better results than the previous Gaussian methods developed for this system, most notably standard linearization techniques.Comment: Comments are welcom

Theory of frequency-filtered and time-resolved N-photon correlations

A theory of correlations between N photons of given frequencies and detected at given time delays is presented. These correlation functions are usually too cumbersome to be computed explicitly. We show that they are obtained exactly through intensity correlations between two-level sensors in the limit of their vanishing coupling to the system. This allows the computation of correlation functions hitherto unreachable. The uncertainties in time and frequency of the detection, which are necessary variables to describe the system, are intrinsic to the theory. We illustrate the formalism with the Jaynes--Cummings model, showing how correlations of various peaks at zero or finite time delays bring new insights into the dynamics of open quantum systems.Comment: 12 pages, 2 figure

Some results on arithmetic codes of composite length

In this paper we present a new upper bound on the minimum distance of binary cyclic arithmetic codes of composite length. Two new classes of binary cyclic codes of composite length are introduced

Optimal Parallel Lexicographic Sorting using a Fine-Grained Decomposition

Though non-comparison based sorting techniques like radix sorting can be done with less work than conventional comparison-based methods, they are not used for long keys. This is because even though parallel radix sorting algorithms process the keys in parallel, the symbols in the keys are processed sequentially. In this report, we give an optimal algorithm for lexicographic sorting that can be used to sort n m-bit keys on an EREW model in Ө (log nlogm) time with Ө (mn) work . This algorithm is not only as fast as any optimal non-comparison based algorithm, but can also be executed with less work. We also use the proposed algorithm to show that if n Ө (log n) unsigned binary numbers can be sorted optimally on an EREW PRAM than n unsigned binary numbers of unrestricted length can be sorted optimally on an EREW PRAM

Optimal Parallel Solutions to the Neighbor Localization Problem and Integer Sorting: A Fine Grained Approach

In this report, a fine-grained decomposition approach is used to obtain an optimal parallel solution to the Neighbor Localization Problem, which in turn is œ used to sort n θ(log n)-bit numbers optimally on an EREW model. The model of computation used is the EREW Reconfigurable PRAM (R-PRAM) that permits the use of “very small” processors. The main result of this report is a parallel EREW R-PRAM algorithm that sorts n θ(log n)-bit numbers in θ(log n) time with θ(n log n) “work”. The proposed algorithm is asymptotically optimal in time and efficiency. If a weaker variant of the R-PRAM (called the ISR-PRAM) is used, the efficiency suffers only a slight degradation

DUAL-MODE SEQUENTIAL LOGIC FOR FUNCTION INDEPENDENT FAULT-TESTING

This paper presents a method of using hardware redundancy to ease the problem of fault testing in sequential logic networks. Sequential logic networks are constructed using two kinds of dual-mode logic gates, one of which is specifically required to initialize a feedback loop to some logic value. Initially, it is shown that these networks can be tested for all single stuck-at-faults with six function-independent tests. Next, this method is generalized to detect large classes of multiple faults with six function-independent tests. In both cases, the network must have the proper number of extra inputs

Efficient Maximum-Likelihood Soft-Decision Decoding of Linear Block Codes Using Algorithm A

In this report we present a novel and efficient maximum-likelihood soft-decision decoding algorithm for linear block codes. The approach used here is to convert the decoding problem into a search problem through a graph which is a trellis for an equivalent code of the transmitted code. Algorithm A*, which uses a priority-first search strategy, is employed to search through this graph. This search is guided by an evaluation function f defined to take advantage of the information provided by the received vector and the inherent properties of the transmitted code. This function f is used to drastically reduce the search space and to make the decoding efforts of this decoding algorithm adaptable to the noise level. Simulation results for the ( 48, 24) and the (72, 36) binary extended quadratic residue codes and the (128, 64) binary extended BCH code are given to substantiate the above claim

Agroecologia e pol?ticas p?blicas:an?lise de processos junto a grupos de fam?lias do n?cleo oeste do Paran? da Rede Ecovida

Understanding from the existing real the constituted social dynamics is the main objective of dialectical historical materialism. Thus, we developed from this method, a study to interpret the phenomena that occur alongside the peasant families of the EcoVida Network of the West of Paran?, who daily challenge themselves to build Agroecology. We support some authors who have discussed this theme in other historical moments to bring a set of elements, to reflect on the current practice. In this way, to interpret with greater clarity the existing material processes and their contradictions, which, in turn, underpin and support the planning of new actions capable of overcoming the limits imposed by the real. The greater capacity of analysis contributes to the determination of new practices more consistent and propulsive, adding more intensity in the development. Permeating this established material base, we have a set of public policies that directly interfere in this rhythm and towards being triggered. These, in turn, fulfill a role of social and productive organization, according to the interests of the Brazilian state. We opted to discuss in the work some of these that relate and interfere directly with this real, bringing elements for discussion and that enabled us to better understand these and their transformation potential. We studied the policies of Agrarian Reform, Pronaf, PNAE and PAA. It was verified, mainly, the non-effectiveness of Pronaf for Agroecology. We present, then, the historical, material and dialectical elements of three groups of farming families of the Ecovida Network and we summarize their main contradictions in the processes and that hamper the development of the material base. development of production "; "Development of productive forces"; "Access to public policies"; "Lack of development of new social relations of production: peasant cooperatives and the Base Groups of the Ecovida Network"; "Supporting entities"; "Availability of workforce". We have identified that public policies aimed at the promotion of agroecology should focus on this chain link (organize the marketproduction process) in order to foster increasing demand and trigger the development of the production of existing agro-ecological groups. Finally, we also emphasize the importance of qualifying and expanding studies on this methodology of analysis by other researchers, based on Historical and Dialectical Materialism, contributing to the advancement of the popular Agroecology project. Keywords: Agroecology, Historical and dialectical materialism, Public policies, Contradictions.Compreender a partir do real existente a din?mica social constitu?da ? o objetivo principal do materialismo hist?rico dial?tico. Assim, desenvolvemos a partir deste m?todo, um estudo para interpretar os fen?menos que ocorrem junto ?s fam?lias camponesas da Rede EcoVida do Oeste do Paran?, que se desafiam cotidianamente em construir Agroecologia. Apoiamo-nos em alguns autores que discutiram esse tema em outros momentos hist?ricos para trazer um conjunto de elementos, para refletirmos sobre a pr?tica atual existente. Desta forma, interpretar com maior clareza os processos materiais existentes e suas contradi??es, que por sua vez, embasam e fundamentam o planejamento de novas a??es capazes de superar os limites impostos pelo real. A maior capacidade de an?lise contribui para a determina??o de novas pr?ticas mais consistentes e propulsoras, agregando maior intensidade no desenvolvimento. Permeando essa base material institu?da, temos um conjunto de pol?ticas p?blicas que interferem diretamente neste ritmo e rumo a ser desencadeado. Estas, por sua vez, cumprem com um papel de organiza??o social e produtiva, conforme os interesses do estado Brasileiro. Optamos em discutir no trabalho algumas destas que se relacionam e interferem diretamente sobre esse real, trazendo elementos para discuss?o e que nos possibilitaram um melhor entendimento destas e seu potencial de transforma??o. Estudamos as pol?ticas de Reforma Agr?ria, Pronaf, PNAE e PAA. Constatou-se, principalmente, a n?o efetividade do Pronaf para a Agroecologia. Apresentamos, na sequ?ncia, os elementos hist?ricos, materiais e dial?ticos de tr?s grupos de fam?lias agricultoras da Rede Ecovida e apontamos de forma sint?tica as suas principais contradi??es existentes nos processos e que emperram o desenvolvimento da base material, sendo elas: ?A comercializa??o para o desenvolvimento da produ??o?; ?Desenvolvimento das For?as produtivas?; ?Acesso ? pol?ticas p?blicas?; ?Car?ncia no desenvolvimento de novas rela??es sociais de produ??o: as cooperativas camponesas e os Grupos de base da Rede Ecovida?; ?Entidades de apoio?; ?disponibilidade de for?a de trabalho?. Identificamos que as pol?ticas p?blicas voltadas ao fomento da agroecologia deveriam concentrar nesse elo da cadeia (organizar o processo mercado-produ??o), de forma a propiciar demanda crescente e desencadear o desenvolvimento da produ??o dos grupos agroecol?gicos j? existentes. Por ?ltimo, destacamos tamb?m a import?ncia de qualificar e ampliar os estudos sobre essa metodologia de an?lise por outros pesquisadores, a partir do Materialismo Hist?rico e Dial?tico, contribuindo para avan?armos no projeto popular da Agroecologia. Palavras-chave: Agroecologia, Materialismo hist?rico e dial?tico, Pol?ticas p?blicas, Contradi??es

A percepção de disfunções ambientais como ferramente de planejamento

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Arquitetura e Urbanismo, Florianópolis, 2009.Desde a promulgação do Estatuto da Cidade as administrações municipais têm direcionado esforços no sentido de adequarem seus processos de planejamento urbano às novas regras. Todos os municípios brasileiros devem orientar e controlar seu desenvolvimento de modo a desenvolver plenamente as funções sociais da cidade e da propriedade urbana, e isso depende da resolução de dois problemas principais: a) a necessidade de alimentar o pensamento técnico dos planejadores urbanos com dados sobre o que os moradores e trabalhadores locais consideram necessário e desejável; e b) alimentar o pensamento dos moradores e trabalhadores locais com informações técnicas que ultrapassam a escala de sua casa e de sua rua. Com o objetivo de tornar possível o planejamento de ações de educação ambiental direcionada para a gestão democrática da cidade, com base em mapas de percepções de disfunções ambientais, foi realizado um estudo experimental em uma vizinhança do Bairro São Lourenço (Curitiba/Paraná). A partir deste estudo, as disfunções ambientais percebidas foram representadas no imóvel do entrevistado. Para isto, os procedimentos seguidos foram: a) a investigação de percepções populares de disfunções existentes na configuração ambiental da vizinhança e de intenções populares de investimento público para corrigir as disfunções percebidas; b) a estruturação dos dados em uma planilha de atributos da área de estudos em um Sistema de Informações Geográficas (ArcMAP 9.2); c) a espacialização e a análise dos dados. Os procedimentos seguidos foram concebidos com o objetivo de efetivamente tornar possível a inclusão da comunidade na gestão democrática da vizinhança a partir da utilização de dados provenientes de percepções populares locais, de modo a estimular o desenvolvimento de comportamentos pró-ambientais, da coesão social e do ativismo cívico. Os resultados obtidos indicam que a espacialização de disfunções percebidas ao nível do imóvel pode produzir mapas temáticos úteis para a sensibilização popular para a questão ambiental e para a mobilização popular para a participação em processos de gestão democrática da cidade, a partir da vizinhança. Recomenda-se a utilização de aplicativos de informática e telemática para agilizar o processo de espacialização dos dados, tornando possível a aplicação dos procedimentos propostos para a sensibilização e a mobilização de grandes contingentes populacionais