Deterministic generation of large-scale entangled photonic cluster state from interacting solid state emitters

The ability to create large highly entangled `cluster' states is crucial for measurement-based quantum computing. We show that deterministic multi-photon entanglement can be created from coupled solid state quantum emitters without the need for any two-qubit gates and regardless of whether the emitters are identical. In particular, we present a general method for controlled entanglement creation by making direct use of the always-on exchange interaction, in combination with single-qubit operations. This is used to provide a recipe for the generation of two-dimensional, cluster-state entangled photons that can be carried out with existing experimental capabilities in quantum dots

Towards practical linear optical quantum computing

Quantum computing promises a new paradigm of computation where information is processed in a way that has no classical analogue. There are a number of physical platforms conducive to quantum computation, each with a number of advantages and challenges. Single photons, manipulated using integrated linear optics, constitute a promising platform for universal quantum computation. Their low decoherence rates make them particularly favourable, however the inability to perform deterministic two-qubit gates and the issue of photon loss are challenges that need to be overcome. In this thesis we explore the construction of a linear optical quantum computer based on the cluster state model. We identify the different necessary stages: state preparation, cluster state construction and implementation of quantum error correcting codes, and address the challenges that arise in each of these stages. For the state preparation, we propose a series of linear optical circuits for the generation of small entangled states, assessing their performance under different scenarios. For the cluster state construction, we introduce a ballistic scheme which not only consumes an order of magnitude fewer resources than previously proposed schemes, but also benefits from a natural loss tolerance. Based on this scheme, we propose a full architectural blueprint with fixed physical depth. We make investigations into the resource efficiency of this architecture and propose a new multiplexing scheme which optimises the use of resources. Finally, we study the integration of quantum error-correcting codes in the linear optical scheme proposed and suggest three ways in which the linear optical scheme can be made fault-tolerant.Open Acces

Physical-depth architectural requirements for generating universal photonic cluster states

Most leading proposals for linear-optical quantum computing (LOQC) use cluster states, which act as a universal resource for measurement-based (one-way) quantum computation (MBQC). In ballistic approaches to LOQC, cluster states are generated passively from small entangled resource states using so-called fusion operations. Results from percolation theory have previously been used to argue that universal cluster states can be generated in the ballistic approach using schemes which exceed the critical threshold for percolation, but these results consider cluster states with unbounded size. Here we consider how successful percolation can be maintained using a physical architecture with fixed physical depth, assuming that the cluster state is continuously generated and measured, and therefore that only a finite portion of it is visible at any one point in time. We show that universal LOQC can be implemented using a constant-size device with modest physical depth, and that percolation can be exploited using simple pathfinding strategies without the need for high-complexity algorithms.Comment: 18 pages, 10 figure

Fault-tolerance thresholds for the surface code with fabrication errors

The construction of topological error correction codes requires the ability to fabricate a lattice of physical qubits embedded on a manifold with a non-trivial topology such that the quantum information is encoded in the global degrees of freedom (i.e. the topology) of the manifold. However, the manufacturing of large-scale topological devices will undoubtedly suffer from fabrication errors---permanent faulty components such as missing physical qubits or failed entangling gates---introducing permanent defects into the topology of the lattice and hence significantly reducing the distance of the code and the quality of the encoded logical qubits. In this work we investigate how fabrication errors affect the performance of topological codes, using the surface code as the testbed. A known approach to mitigate defective lattices involves the use of primitive SWAP gates in a long sequence of syndrome extraction circuits. Instead, we show that in the presence of fabrication errors the syndrome can be determined using the supercheck operator approach and the outcome of the defective gauge stabilizer generators without any additional computational overhead or the use of SWAP gates. We report numerical fault-tolerance thresholds in the presence of both qubit fabrication and gate fabrication errors using a circuit-based noise model and the minimum-weight perfect matching decoder. Our numerical analysis is most applicable to 2D chip-based technologies, but the techniques presented here can be readily extended to other topological architectures. We find that in the presence of 8% qubit fabrication errors, the surface code can still tolerate a computational error rate of up to 0.1%.Comment: 10 pages, 15 figure

Trabajo de titulación bajo la modalidad de Estudio Técnico previo a la obtención del título de Ingeniera Industrial

El presente proyecto técnico tuvo como objetivo analizar el material particulado como riesgo en la salud de los trabajadores de la empresa “FIBER AND GLASS PLÁSTICOS REFORZADOS” de la ciudad de Ambato. Para determinar el área con la mayor cantidad de material particulado. Se elaboró una matriz de presencia y tiempo de exposición del mismo, determinando el área de pulido como sección de estudio. Se realizaron observaciones de acciones y condiciones subestándares en el área que dio como resultado la presencia de riesgos. Se tabuló el cuestionario de síntomas respiratorios ATS-DLD 78 aplicado a los trabajadores de la empresa para conocer si presentan sintomatología respiratoria y se realizó un diagnóstico médico para conocer el estado del personal del área seleccionada. Con el contador de partículas de mano AEROCET 531S se tomaron muestras en cinco días distintos a los tres trabajadores del área de pulido, en donde se calculó el valor del índice de exposición considerando según OSHA de 15 mg/m3 para el total de partículas de polvo de fibra de vidrio para un turno de 8 horas, y se obtuvo en promedio 0,008 de PM 2,5 µm considerado aceptable y 1,178 de PM 10 µm considerado inaceptable. En función a los resultados obtenidos se concluye que existe un nivel de riesgo importante, debido a que la concentración de PM 10 µm supera los límites de exposición permisibles, y al ser ésta una partícula de mayor densidad ocasiona afecciones respiratorias confirmadas con el diagnóstico médico

Diseño e implementación de un sistema de Control Interno para la Compañía "DATUGOURMET CIA. LTDA.

El presente trabajo documenta el diseño e implementación de un Sistema de Control Interno para una empresa privada domiciliada en la ciudad de Quito – Ecuador; empresa dedicada a la venta de productos alimenticios de alta calidad; para supermercados, hoteles y restaurantes de prestigio o de comidas especializadas. El estudio inicia con la aplicación de la herramienta administrativa llamada FODA (fortalezas, oportunidades, debilidades y amenazas), en busca de factores internos y externos,que contribuyan a la determinación, formulación e implementación de controles claves para el fortalecimiento de su ambiente de controlThis paper documents the design and implementation of an Internal Control System for a private company established in Quito - Ecuador, a company dedicated to selling high quality food products, to supermarkets, hotels and prestigious restaurants or food specialized. The study begins with the application of the administrative tool called SWOT (strengths, weaknesses, opportunities and threats), looking for internal and external factors that contribute to the identification,formulation and implementation of key controls to strengthen its control environment

From three-photon GHZ states to ballistic universal quantum computation

Single photons, manipulated using integrated linear optics, constitute a promising platform for universal quantum computation. A series of increasingly efficient proposals have shown linear-optical quantum computing to be formally scalable. However, existing schemes typically require extensive adaptive switching, which is experimentally challenging and noisy, thousands of photon sources per renormalized qubit, and/or large quantum memories for repeat-until-success strategies. Our work overcomes all these problems. We present a scheme to construct a cluster state universal for quantum computation, which uses no adaptive switching, no large memories, and which is at least an order of magnitude more resource-efficient than previous passive schemes. Unlike previous proposals, it is constructed entirely from loss-detecting gates and offers a robustness to photon loss. Even without the use of an active loss-tolerant encoding, our scheme naturally tolerates a total loss rate of $\sim 1.6\%$ in the photons detected in the gates. This scheme uses only 3-GHZ states as a resource, together with a passive linear-optical network. We fully describe and model the iterative process of cluster generation, including photon loss and gate failure. This demonstrates that building a linear optical quantum computer need be less challenging than previously thought.Comment: Minor changes to match published version. 10 pages and 14 figures including the supplementary materia

Efectos sobre la cultura organizacional a partir de una transformación institucional. Caso de estudio: Registro Civil de Quito

La presente investigación estudia el proceso de modernización ejecutado por el Registro Civil en el año 2010, como una de las instituciones más emblemáticas en ejecutar una reforma administrativa, enmarcada en la transformación institucional reciente del Ecuador. El desarrollo teórico toma como soporte fundamental la teoría de la Nueva Gestión Pública, misma que se ubica dentro del nuevo paradigma de administración pública denominado postburocrático, relacionando la importancia del estudio con la cultura organizacional y como ésta se convierte en elemento clave que garantizará el éxito o fracaso en los procesos de modernización de las instituciones públicas. Por otro lado el estudio de la teoría de las organizaciones y cambio organizacional es transversal en la investigación, pues permiten comprender la importancia de la interrelación e interdependencia de todos los actores e involucrados dentro de las instituciones. La metodología empleada es un Estudio de Caso, método científico que permite, a través de una secuencia lógica de pasos, comprobar el supuesto de investigación: “en los procesos de transformación institucional, que son aplicados por normatividad y a través de herramientas de gestión, no involucran el análisis de la cultura organizacional en su implementación”

Relative multiplexing for minimizing switching in linear-optical quantum computing

Many existing schemes for linear-optical quantum computing (LOQC) depend on multiplexing (MUX), which uses dynamic routing to enable near-deterministic gates and sources to be constructed using heralded, probabilistic primitives. MUXing accounts for the overwhelming majority of active switching demands in current LOQC architectures. In this manuscript, we introduce relative multiplexing (RMUX), a general-purpose optimization which can dramatically reduce the active switching requirements for MUX in LOQC, and thereby reduce hardware complexity and energy consumption, as well as relaxing demands on performance for various photonic components. We discuss the application of RMUX to the generation of entangled states from probabilistic single-photon sources, and argue that an order of magnitude improvement in the rate of generation of Bell states can be achieved. In addition, we apply RMUX to the proposal for percolation of a 3D cluster state in [PRL 115, 020502 (2015)], and we find that RMUX allows a 2.4x increase in loss tolerance for this architecture.Comment: Published version, New Journal of Physics, Volume 19, June 201

Los rincones de trabajo y el proceso de enseñanza aprendizaje

Early childhood education, primary part for development and obtaining meaningful learning, to provide the proper development of children / as. The purpose of this research was to investigate the Learning Early Education Process to see the impact of work corners of children / as of the second stage of the Center for Early Education "Semillitas" Cesar Francisco Naranjo Rumazo, the main objective is determine the correct use of work corners and development in the teaching-learning process, through surveys and direct observation to avoid possible educational problems. To solve this problem activities which enable teachers enjoy a range of practical activities according to the study corner mostly workshops where teachers will be active participants arises, and will help to provide input on training, experience and creativity of teachers to learn optimize the use of each of the corners and whoever they generate diverse and innovative proposals to stimulate learning and development of children / as, target is met within the framework of Early Childhood Education. After assessing the instruments of research, concluded that teachers had no basis for the use of every corner of work on all the time is not optimized to stimulate learning in these spaces, they have not been renovated or are changed periodically corners so the loss of interest by children / as is demonstrated.La educación inicial, parte primordial para el desarrollo y obtención del aprendizaje significativo, para aportar en el correcto desenvolvimiento de los niños/as. El propósito de esta investigación fue indagar en el Proceso Enseñanza Aprendizaje de Educación Inicial para ver la incidencia de los rincones de trabajo de los niños/as de la segunda etapa del Centro de Educación Inicial “Semillitas” Cesar Francisco Naranjo Rumazo, el objetivo principal es determinar el correcto uso de los rincones de trabajo y el desarrollo en el proceso de enseñanza aprendizaje, a través de encuestas y la observación directa para evitar posibles problemas educativos. Para la resolución de esta problemática se plantea actividades las que permitirán a los docentes gozar de una gama de actividades prácticas acorde al rincón de trabajo sobre todo talleres en donde los docentes serán participantes activos, así se contribuirá a brindar aportes en la formación, experiencia y creatividad de los docentes para saber optimizar el uso de cada uno de los rincones y sean quienes generen propuestas diversas e innovadoras para estimular el aprendizaje y el desarrollo de los niños/as, objetivo que se cumple en el marco de la Educación Inicial. Luego de valorar los instrumentos de investigación, se llegó a la conclusión que los docentes no tenían bases para la utilización de cada rincón de trabajo sobre todo no se optimiza el tiempo para estimular el aprendizaje en estos espacios, no se han renovado ni se cambian periódicamente los rincones por lo que se demuestra la perdida de interés por parte de los niños/as