A simple method to construct Flat Band lattices

We develop a simple and general method to construct arbitrary Flat Band lattices. We identify the basic ingredients behind zero-dispersion bands and develop a method to construct extended lattices based on a consecutive repetition of a given mini-array. The number of degenerated localized states is defined by the number of connected mini-arrays times the number of modes preserving the symmetry at a given connector site. In this way, we create one or more (depending on the lattice geometry) complete degenerated Flat Bands for quasi-one and two-dimensional systems. We probe our method by studying several examples, and discuss the effect of additional interactions like anisotropy or nonlinearity. At the end, we test our method by studying numerically a ribbon lattice using a continuous description.Comment: 11 pages, 11 figure

Quantum localized states in photonic flat-band lattices

The localization of light in flat-band lattices has been recently proposed and experimentally demonstrated in several configurations, assuming a classical description of light. Here, we study the problem of light localization in the quantum regime. We focus on quasi one-dimensional and two-dimensional lattices which exhibit a perfect flat-band inside their linear spectrum. Localized quantum states are constructed as eigenstates of the interaction Hamiltonian with a vanishing eigenvalue and a well defined total photon number. These are superpositions of Fock states with probability amplitudes given by positive as well as negative square roots of multinomial coefficients. The classical picture can be recovered by considering poissonian superpositions of localized quantum states with different total photon number. We also study the separability properties of flat band quantum states and apply them to the transmission of information via multi-core fibers, where these states allow for the total passive suppression of photon crosstalk and exhibit robustness against photon losses. At the end, we propose a novel on-chip setup for the experimental preparation of localized quantum states of light for any number of photons.Comment: 12 pages, 5 figure

A simple method for estimating suitable territory for bioenergy species in Chile

Artículo de publicación ISIIn the past 20 years, different areas of research concerning native and exotic species, herbaceous crops and forest plantations have been oriented toward satisfying domestic, industrial and transportation energy requirements. Because bioenergy species constitute an important resource, it would be strategic for a country to have a method for identifying areas suitable for their cultivation to properly incorporate the establishment of energy crops into land use planning. In this study, we sought to define the suitable territories for 16 bioenergy species and their energy potential based on their soil and climate requirements in Central and Southern Chile. We used an adapted version of the FAO EcoCrop database implemented through DIVA-GIS software to predict the crop suitability of different geographical areas, and our results indicate that this method is a simple way to identify land suitable for the establishment of bioenergy species, which is information that can be used in land use planning. Furthermore, spatially explicit regression and ordinary kriging proved to be satisfactory tools for interpolating data from weather station networks through the generation of continuous climatic information grids. Land suitability is presented at a scale of 1:1,000,000 in a continuous digital format expressed in probabilistic terms.Technological Consortium on Biofuels (Biocomsa) - CORFO-Innova 08CTE02-06 "Programa de Insercion de Capital Humano Avanzado en la Academia" project, CONICYT (Comision Nacional de Investigacion Cientifica y Tecnologica, Chile) 7909001

A simple method for estimating suitable territory for bioenergy species in Chile

In the past 20 years, different areas of research concerning native and exotic species, herbaceous crops and forest plantations have been oriented toward satisfying domestic, industrial and transportation energy requirements. Because bioenergy species constitute an important resource, it would be strategic for a country to have a method for identifying areas suitable for their cultivation to properly incorporate the establishment of energy crops into land use planning. In this study, we sought to define the suitable territories for 16 bioenergy species and their energy potential based on their soil and climate requirements in Central and Southern Chile. We used an adapted version of the FAO EcoCrop database implemented through DIVA-GIS software to predict the crop suitability of different geographical areas, and our results indicate that this method is a simple way to identify land suitable for the establishment of bioenergy species, which is information that can be used in land use planning. Furthermore, spatially explicit regression and ordinary kriging proved to be satisfactory tools for interpolating data from weather station networks through the generation of continuous climatic information grids. Land suitability is presented at a scale of 1:1,000,000 in a continuous digital format expressed in probabilistic terms.En estos últimos 20 años diversas líneas de investigación en especies nativas y exóticas, cultivos herbáceos y plantaciones forestales se han orientado al desarrollo de aplicaciones energéticas domésticas, industriales y para el transporte. Como son un recurso importante, es estratégico contar con un método que permita identificar en el territorio nacional las áreas con aptitud para el cultivo de estas especies, con el objetivo de realizar una planificación territorial adecuada para el establecimiento de las plantaciones bioenergéticas. En este estudio se presenta un método simple para definir la idoneidad territorial de 16 especies con potencial energético (El Bassam, 2010) en el Centro y Sur de Chile, en base a sus requerimientos de suelo y clima. Se utilizó una adaptación del método EcoCrop implementado en el software DIVA-GIS para predecir la idoneidad de los cultivos en dicha zona geográfica. Los resultados muestran que el método propuesto representa una forma sencilla de estimar las zonas del territorio con idoneidad adecuada para establecer plantaciones bioenergéticas específicas, información que puede ser utilizada para la toma de decisiones en la planificación del territorio. La regresión espacialmente explicita y el kriging ordinario mostraron ser una herramienta satisfactoria de interpolación de los datos obtenidos de redes de estaciones climáticas para la generación de rejillas continuas de datos climáticos. La idoneidad territorial se presenta en un formato digital continuo expresado en términos probabilísticos a una escala 1:1,000,000

Truncated Metallo-Dielectric Omnidirectional Reflector: Collecting Single Photons in the Fundamental Gaussian Mode with 95% Efficiency

We propose a novel antenna structure that funnelssingle photons from a single emitter with unprecedented efficiencyinto a low-divergence fundamental Gaussian mode. Our devicerelies on the concept of creating an omnidirectional photonicbandgap to inhibit unwanted large-angle emission and to enhancesmall-angle defect-guided-mode emission. The new photoncollection strategy is intuitively illustrated, rigorously verified,and optimized by implementing an efficient, body-of-revolution,finite-difference, time-domain method for in-plane dipole emitters.We investigate a few antenna designs to cover various boundaryconditions posed by fabrication processes or material restrictions and theoretically demonstrate that collection efficiencies into thefundamental Gaussian mode exceeding 95% are achievable. Our antennas are broadband, insensitive to fabrication imperfections andcompatible with a variety of solid-state emitters such as organic molecules, quantum dots, and defect centers in diamond.Unidirectional and low-divergence Gaussian-mode emission from a single emitter may enable the realization of a variety of photonicquantum computer architectures as well as highly efficient light−matter interfaces