Computational Study Of The Near Field Spontaneous Creation Of Photonic States Coupled To Few Level Systems

Models of the spontaneous emission and absorption of photons coupled to the electronic states of quantum dots, molecules, N-V (single nitrogen vacancy) centers in diamond, that can be modeled as artificial few level atoms, are important to the development of quantum computers and quantum networks. A quantum source modeled after an effective few level system is strongly dependent on the type and coupling strength the allowed transitions. These selection rules are subject to the Wigner-Eckert theorem which specifies the possible transitions during the spontaneous creation of a photonic state and its subsequent emission. The model presented in this dissertation describes the spatio-temporal evolution of photonic states by means of a Dirac-like equation for the photonic wave function within the region of interaction of a quantum source. As part of this aim, we describe the possibility to shift from traditional electrodynamics and quantum electrodynamics, in terms of electric and magnetic fields, to one in terms of a photonic wave function and its operators. The mapping between these will also be presented herein. It is further shown that the results of this model can be experimentally verified. The suggested method of verification relies on the direct comparison of the calculated density matrix or Wigner function, associated with the quantum state of a photon, to ones that are experimentally reconstructed through optical homodyne tomography techniques. In this non-perturbative model we describe the spontaneous creation of photonic state in a non-Markovian limit which does not implement the Weisskopf-Wigner approximation. We further show that this limit is important for the description of how a single photonic mode is created from the possibly infinite set of photonic frequencies νk that can be excited in a dielectric-cavity from the vacuum state. We use discretized central-difference approximations to the space and time partial derivatives, similar to finite-difference time domain models, to compute these results. The results presented herein show that near field effects need considered when describing adjacent quantum sources that are separated by distances that are small with respect to the wavelength of iii their spontaneously created photonic states. Additionally, within the future scope of this model, we seek results in the Purcell and Rabi regimes to describe enhanced spontaneous emission events from these few-level systems, as embedded in dielectric cavities. A final goal of this dissertation is to create novel computational and theoretical models that describe single and multiple photon states via single photon creation and annihilation operators

Applicability of hybrid density functional theory methods to calculation of molecular hyperpolarizability

The donor/acceptor (D/A) substituted pi-conjugated organic molecules possess extremely fast nonlinear optical (NLO) response time that is purely electronic in origin. This makes them promising candidates for optoelectronic applications. In the present study, we utilized four hybrid density functionals (B3LYP, B97-2, PBE0, BMK), Hartree-Fock, and second order Moller-Plesset correlation energy correction, truncated at second-order (MP2) methods with different basis sets to estimate molecular first hyperpolarizability (beta) of D/A-substituted benzenes and stilbenes (D=OMe, OH, NMe2, NH2; A=NO2, CN). The results of density functional theory (DFT) calculations are compared to those of MP2 method and to the experimental data. We addressed the following questions: (1) the accurate techniques to compare calculated results to each other and to experiment, (2) the choice of the basis set, (3) the effect of molecular planarity, and (4) the choice of the method. Comparison of the absolute values of hyperpolarizabilities obtained computationally and experimentally is complicated by the ambiguities in conventions and reference values used by different experimental groups. A much more tangible way is to compare the ratios of beta\u27s for two (or more) given molecules of interest that were calculated at the same level of theory and measured at the same laboratory using the same conventions and reference values. Coincidentally, it is the relative hyperpolarizabilities rather than absolute ones that are of importance in the rational molecular design of effective NLO materials. This design includes prediction of the most promising candidates from particular homologous series, which are to be synthesized and used for further investigation. In order to accomplish this goal, semiquantitative level of accuracy is usually sufficient. Augmentation of the basis set with polarization and diffuse functions changes beta by 20%; however, further extension of the basis set does not have significant effect. Thus, we recommend 6-31+G(*) basis set. We also show that the use of planar geometry constraints for the molecules, which can somewhat deviate from planarity in the gas phase, leads to sufficient accuracy (with an error less than 10%) of predicted values. For all the molecules studied, MP2 values are in better agreement with experiment, while DFT hybrid methods overestimate beta values. BMK functional gives the best agreement with experiment, with systematic overestimation close to the factor of 1.4. We propose to use the scaled BMK results for prediction of molecular hyperpolarizability at semiquantitative level of accuracy

Double excitations and state-to-state transition dipoles in pi-pi* excited singlet states of linear polyenes: Time-dependent density-functional theory versus multiconfigurational methods

The effect of static and dynamic electron correlation on the nature of excited states and state-to-state transition dipole moments is studied with a multideterminant wave function approach on the example of all-trans linear polyenes (C4H6, C6H8, and C8H10). Symmetry-forbidden singlet nA(g) states were found to separate into three groups: purely single, mostly single, and mostly double excitations. The excited-state absorption spectrum is dominated by two bright transitions: 1B(u)-2A(g) and 1B(u)-mA(g), where mA(g) is the state, corresponding to two-electron excitation from the highest occupied to lowest unoccupied molecular orbital. The richness of the excited-state absorption spectra and strong mixing of the doubly excited determinants into lower-nA(g) states, reported previously at the complete active space self-consistent field level of theory, were found to be an artifact of the smaller active space, limited to pi orbitals. When dynamic sigma-pi correlation is taken into account, single- and double-excited states become relatively well separated at least at the equilibrium geometry of the ground state. This electronic structure is closely reproduced within time-dependent density-functional theory (TD DFT), where double excitations appear in a second-order coupled electronic oscillator formalism and do not mix with the single excitations obtained within the linear response. An extension of TD DFT is proposed, where the Tamm-Dancoff approximation (TDA) is invoked after the linear response equations are solved (a posteriori TDA). The numerical performance of this extension is validated against multideterminant-wave-function and quadratic-response TD DFT results. It is recommended for use with a sum-over-states approach to predict the nonlinear optical properties of conjugated molecules

La Informalidad en Granada Incide en la Evasión de Industria y Comercio./

188 (36) h.Analizar la incidencia de la informalidad en la evasión de impuesto de Industria y Comercio en el año fiscal 2015, en el municipio de Granada. Interpretar estadísticamente la información suministrada por los comerciantes a través de la encuesta, permitiendo identificar las causas que generan la informalidad en los comerciantes del municipio de Granada. Describir las causas por los cuales se presenta el fenómeno de la informalidad comercial, mediante la información. Calcular una proyección sobre los ingresos dejados de percibir en el Impuesto de Industria y Comercio, con base a la simulación de los estados financieros de acuerdo a la investigación.Resultado para Optar el Título de Contador Público, Tesis(Contador Público). Universidad de los Llanos. Facultad de Ciencias Económicas.Programa de Contaduría Publica , 2016PregradoContaduría Públic

El Arbitraje Administrativo en la contratación pública peruana: ¿evolución o contradicción?

Due to modern times, many commercial relations have emerged and have led society to new types of conflict that require to be analyzed with particular attention. This context has shown that the ordinary instances of law do not have the necessary knowledge to face this type of conflicts. Thereby, modern law, as a social phenomenon, has adapted to this evolution. This is where arbitration has progressively become more relevant over the years. Because traditional legal branches, such as the Judiciary system, are not efficient enough to resolve disputes in their jurisdiction. By virtue of this, the Peruvian State, within its legal framework, has established the figure of arbitration as a means of bypassing national judicial courts in order to settle governmental and private entity disputes. To such an extent that the government itself in its PublicProcurement Act of 2008 —published through Legislative Decree 1017— mentioned the concept of “administrative arbitration”, which is still used today without having a clear and precise definition. The purpose of this article is to develop this figure based on the reason for its creation and to analyze whether this figure finds a reason to exist in the current context of public procurement or if it constitutes a legal chimera still in the making. Therefore, our intention in the following lines, without being exhaustive, is to give a brief reflection on the importance of administrative arbitration regulation regarding the concept of arbitration and to analyze if this figure already exists in the current Peruvian framework or, on the contrary, if we are before the bureaucratization of the institution.Con el devenir de la modernidad han surgido relaciones comerciales de diversa índole que han derivado en nuevos tipos de conflicto y que requieren una particular atención. Este contexto ha demostrado, con meridiana claridad, que las instancias ordinarias del Derecho no tienen el expertise necesario para afrontar este tipo de problemas. Así, el Derecho moderno, al ser un fenómeno social, ha ido adaptándose a estaevolución. En ese ámbito, es donde progresivamente el arbitraje ha tomado mayor relevancia con los años. Actualmente, los estamentos legales tradicionales, como el Poder Judicial, más allá de su evidente impericia en ciertas materias, no se dan abasto para solucionar con eficiencia las controversias sometidas a su jurisdicción. En virtud de ello, el Estado peruano, dentro de su marco legal, ha dispuesto a la figura del arbitraje como un medio para evitar los tribunales judiciales nacionales a fin de resolver las disputas entre entidades gubernamentales y privados. A tal punto que el mismo Estado en su Ley de Contrataciones con el Estado del año 2008 —publicada mediante el Decreto Legislativo 1017— mencionó el concepto de arbitraje administrativo, el cual aún es usado en nuestros días sin tener una definición clara y precisa. El objeto del presente artículo pretende desarrollar esta figura partiendo del por qué de la misma y analizar si esta encuentra una razón de existir en el contexto actual de Contrataciones con el Estado o si la misma constituye una quimera jurídica aún en formación. En suma, nuestra intención en las siguientes líneas, sin ser exhaustivos, es dar una breve reflexión sobre lo que de cara al arbitraje importa la regulación del arbitraje administrativo y analizar si esta figura ya existe en el marco actual o, por el contrario, nos encontramos ante una burocratización de la figura

Evaluación del comportamiento sísmico en sistemas losa columna, fabricados en concreto con fibras de acero

Es el objetivo del presente documento, evaluar el cortante y la capacidad de disipación de energía en sistemas losa columna fabricados en concreto con fibras de acero ante esfuerzos de punzonamiento. Lo anterior, mediante el diseño de un modelo experimental que permita generar falla debida a esfuerzos punzantes, así como la realización y posterior falla de 5 sistemas losa columna, de los cuales 3 serán elaborados con fibra, uno de ellos con armado a punzonamiento y finalmente uno de control (sin fibra). De acuerdo a lo anterior, se espera demostrar la mejora de un concreto elaborado con fibras de acero no solo a soportar esfuerzos cortantes, sino también en el incremento de la disipación de energía del mismo.It is the purpose of this paper to evaluate the shear and the energy dissipation capacity in concrete column systems and steel fibers in the face of punching forces. The above, by designing an experimental model that fails to generate failure due to the punching forces, as well as the realization and subsequent failure of 5 column systems, of which 3 are made with fiber, one of them with reinforcement A punching and finally a control (without fiber). Accordingly, it is expected to demonstrate the improvement of a concrete made with the steel fibers not only to withstand shear stresses but also in increasing the energy dissipation thereof.Magíster en Ingeniería CivilMaestrí

Evaluación de la capacidad de disipación de energía de sistemas losa columna fabricados en concreto con fibras de acero

Es el objetivo del presente documento, evaluar la capacidad de disipación de energía en sistemas losa columna fabricados en concreto con fibras de acero ante esfuerzos de punzonamiento. Lo anterior, mediante el diseño de un modelo experimental que permita generar falla debida a esfuerzos cortantes, así como la realización y posterior falla de 2 sistemas losa columna, de los cuales uno de ellos fue elaborado en concreto simple, y el otro realizado en 3 losas con adición de fibra, con el fin de comparar la capacidad de disipación de energía de un sistema elaborado en concreto con fibras de acero con respecto a uno elaborado en concreto convencional. De acuerdo a lo anterior, se espera demostrar la mejora de un concreto elaborado con fibras de acero no solo a soportar esfuerzos cortantes, sino también para suministrarle un aumento en la disipación de energía de los sistemas y por ende una mayor ductilidad a la falla.It is the aim of this document, evaluate the energy dissipation in flat slab systems elaborated in reinforced concrete with steel fibers subjected to punching efforts. This, not only by designing an experimental model that allows punching failure, but also by the elaboration and subsequent failure of 4 flat-slab systems, of which one of those will be elaborated in conventional concrete, in order to compare the energy dissipation capacity of a flat-slab system elaborated in reinforced concrete with steel fibers to a conventional concrete system. According to the above, it is expected to demonstrate not only the improvement of a steel fiber concrete subjected to punching efforts but also the increase in the energy dissipation of those flat-slab systems elaborated with steel fibers.Ingeniero (a) CivilPregrad

Phylogenetic relationships among Staphylococcus species and refinement of cluster groups based on multilocus data

Background: Estimates of relationships among Staphylococcus species have been hampered by poor and inconsistent resolution of phylogenies based largely on single gene analyses incorporating only a limited taxon sample. As such, the evolutionary relationships and hierarchical classification schemes among species have not been confidently established. Here, we address these points through analyses of DNA sequence data from multiple loci (16S rRNA gene, dnaJ, rpoB, and tuf gene fragments) using multiple Bayesian and maximum likelihood phylogenetic approaches that incorporate nearly all recognized Staphylococcus taxa. Results: We estimated the phylogeny of fifty-seven Staphylococcus taxa using partitioned-model Bayesian and maximum likelihood analysis, as well as Bayesian gene-tree species-tree methods. Regardless of methodology, we found broad agreement among methods that the current cluster groups require revision, although there was some disagreement among methods in resolution of higher order relationships. Based on our phylogenetic estimates, we propose a refined classification for Staphylococcus with species being classified into 15 cluster groups (based on molecular data) that adhere to six species groups (based on phenotypic properties). Conclusions: Our findings are in general agreement with gene tree-based reports of the staphylococcal phylogeny, although we identify multiple previously unreported relationships among species. Our results support the general importance of such multilocus assessments as a standard in microbial studies to more robustly infer relationships among recognized and newly discovered lineages

Longitudinal genetic analyses of Staphylococcus aureus nasal carriage dynamics in a diverse population

Background: Staphylococcus aureus (SA) nasal colonization plays a critical role in the pathogenesis of staphylococcal infections and SA eradication from the nares has proven to be effective in reducing endogenous infections. To understand SA nasal colonization and its relation with consequent disease, assessment of nasal carriage dynamics and genotypic diversity among a diverse population is a necessity. Results: We have performed extensive longitudinal monitoring of SA nasal carriage isolates in 109 healthy individuals over a period of up to three years. Longitudinal sampling revealed that 24% of the individuals were persistent SA nasal carriers while 32% were intermittent. To assess the genetic relatedness between different SA isolates within our cohort, multi locus sequence typing (MLST) was performed. MLST revealed that not only were strains colonizing intermittent and persistent nasal carriers genetically similar, belonging to the same clonal complexes, but strain changes within the same host were also observed over time for both types of carriers. More highly discriminating genetic analyses using the hypervariable regions of staphylococcal protein A and clumping factor B virulence genes revealed no preferential colonization of specific SA strains in persistent or intermittent carriers. Moreover, we observed that a subset of persistent and intermittent carriers retained clinically relevant community-acquired methicillin-resistant SA (CA-MRSA) strains in their nares over time. Conclusions: The findings of this study provides added perspective on the nasal carriage dynamics between strains colonizing persistent and intermittent carriers; an area currently in need of assessment given that persistent carriers are at greater risk of autoinfection than intermittent carriers