Renormalization algorithm for the calculation of spectra of interacting quantum systems

We present an algorithm for the calculation of eigenstates with definite linear momentum in quantum lattices. Our method is related to the Density Matrix Renormalization Group, and makes use of the distribution of multipartite entanglement to build variational wave--functions with translational symmetry. Its virtues are shown in the study of bilinear--biquadratic S=1 chains.Comment: Corrected version. We have added an appendix with an extended explanation of the implementation of our algorith

High-Precision Numerical Determination of Eigenvalues for a Double-Well Potential Related to the Zinn-Justin Conjecture

A numerical method of high precision is used to calculate the energy eigenvalues and eigenfunctions for a symmetric double-well potential. The method is based on enclosing the system within two infinite walls with a large but finite separation and developing a power series solution for the Schr$\ddot{o}$dinger equation. The obtained numerical results are compared with those obtained on the basis of the Zinn-Justin conjecture and found to be in an excellent agreement.Comment: Substantial changes including the title and the content of the paper 8 pages, 2 figures, 3 table

Perturbation Theory with a Variational Basis: the Generalized Gaussian Effective Potential

The perturbation theory with a variational basis is constructed and analyzed.The generalized Gaussian effective potential is introduced and evaluated up to the second order for selfinteracting scalar fields in one and two spatial dimensions. The problem of the renormalization of the mass is discussed in details. Thermal corrections are incorporated. The comparison between the finite temperature generalized Gaussian effective potential and the finite temperature effective potential is critically analyzed. The phenomenon of the restoration at high temperature of the symmetry broken at zero temperature is discussed.Comment: RevTex, 49 pages, 16 eps figure

Future cities: 28th eCAADe Conference Proceedings

Future Cities - the title of the 2010 eCAADe Conference describes one of the major challenges of the 21st century. The conference theme is a logical evolution from previous years in that it expands the focus of interest from the building to larger scales and higher complexity. The conference contributions describe methods and instruments that were developed in the last three decades and apply them to city and territorial planning. The eCAADe proceedings demonstrate that CAAD research and education of the past prepared the ground for the future and for the increased responsibility of the CAAD community

Custos da qualidade e da manufatura: um estudo de caso na indústria química Quality and manufacturing cost: a case study in the chemical industry

Este trabalho relata um estudo de caso envolvendo a otimização experimental de uma receita química. O estudo abrange as etapas de identificação do problema, planejamento do experimento, modelagem individual das variáveis de resposta, definição de uma função objetivo e otimização. Na identificação do problema e no planejamento do experimento foi utilizada uma estrutura matricial para reunir e organizar as informações. O experimento contemplou cinco fatores controláveis e dez variáveis de resposta. Na etapa de modelagem individual, foram construídos modelos para a média e a variabilidade de cada uma das variáveis de resposta. A função objetivo utilizada no estudo de otimização foi a Função de Perda Quadrática Multivariada, proposta por Ribeiro & Elsayed, acrescida dos custos de matéria prima e energia. Assim, a otimização foi conduzida levando em conta tanto os custos decorrentes da má qualidade (capturados pela função de perda) como os custos de matéria prima e energia. A otimização permitiu definir o melhor ajuste para os fatores controláveis. Ao final é feita uma análise de sensibilidade e é sugerido um envelope de operação para o controle do processo.<br>This paper presents a case study where the optimization of a chemical mixture was accomplished. The study included the following steps: problem identification, design of an experiment, model building for each individual response, choice of an objective function, and optimization. In the steps of problem identification and design of the experiment, a matrix was used to gather and to organize the information. Five control factors and ten response variables were included in the experiment. In the step of model building, models for mean and variability for each response variable were built. The objective function used for optimization was an extended version of the Multivariate Quadratic Loss Function proposed by Ribeiro & Elsayed (1995). The optimization was carried out taking into account the losses due to poor quality as well as the losses due to the costs of raw materials and energy. After the optimization it was possible to identify the best set for the control factors. A sensibility analysis was performed and an operational envelop for process control is suggested