Intrinsically stable light source at telecom wavelengths

We present a highly stable light source at telecom wavelengths, based on a short erbium doped fiber. The high stability arises from the high inversion of the Er3+ion population. This source is developed to work as a stable reference in radiometric applications and is useful in any application where high stability and/or a large bandwidth are necessary. The achieved long-term stability is 10 ppm

Towards Complexity for Quantum Field Theory States

We investigate notions of complexity of states in continuous quantum-many body systems. We focus on Gaussian states which include ground states of free quantum field theories and their approximations encountered in the context of the continuous version of Multiscale Entanglement Renormalization Ansatz. Our proposal for quantifying state complexity is based on the Fubini-Study metric. It leads to counting the number of applications of each gate (infinitesimal generator) in the transformation, subject to a state-dependent metric. We minimize the defined complexity with respect to momentum preserving quadratic generators which form $\mathfrak{su}(1,1)$ algebras. On the manifold of Gaussian states generated by these operations the Fubini-Study metric factorizes into hyperbolic planes with minimal complexity circuits reducing to known geodesics. Despite working with quantum field theories far outside the regime where Einstein gravity duals exist, we find striking similarities between our results and holographic complexity proposals.Comment: 6+7 pages, 6 appendices, 2 figures; v2: references added; acknowledgments expanded; appendix F added, reviewing similarities and differences with hep-th/1707.08570; v3: version published in PR

Measuring absolute spectral radiance using an Erbium Doped Fibre Amplifier

We describe a method to measure the spectral radiance of a source in an absolute way without the need of a reference. Here we give the necessary detail to allow for the device to be reproduced from standard fiber-optic components. The device is suited for fiber-optic applications at telecom wavelengths and calibration of powermeters and spectrometers at light levels from 1nW to 1uW

The Effect of Recency to Human Mobility

In recent years, we have seen scientists attempt to model and explain human dynamics and, in particular, human movement. Many aspects of our complex life are affected by human movements such as disease spread and epidemics modeling, city planning, wireless network development, and disaster relief, to name a few. Given the myriad of applications it is clear that a complete understanding of how people move in space can lead to huge benefits to our society. In most of the recent works, scientists have focused on the idea that people movements are biased towards frequently-visited locations. According to them, human movement is based on an exploration/exploitation dichotomy in which individuals choose new locations (exploration) or return to frequently-visited locations (exploitation). In this work, we focus on the concept of recency. We propose a model in which exploitation in human movement also considers recently-visited locations and not solely frequently-visited locations. We test our hypothesis against different empirical data of human mobility and show that our proposed model is able to better explain the human trajectories in these datasets

La consulta judicial de constitucionalidad de normas, la tutela efectiva y el debido proceso

Desde el 20 de Octubre del 2008, fecha que entró en vigencia la Constitución de la República del Ecuador, la concepción filosófica del Estado cambió. El auto determinante de “Estado constitucional de derechos y justicia social”, implicó algo más que enunciar un objetivo, impuso los valores como materia y contenido de los preceptos normativos, que marcan la validez del ordenamiento jurídico interno, y además, reconoce la fuerza irradiante de la Constitución sobre el infraderecho. La vinculación de la moral y la justicia en el Derecho objetivo, convierte a un Estado de Derecho positivo, en un Estado constitucional de derechos y justicia social, cuya misión es proteger los valores y principios consagrados en la Constitución, creando para ello mecanismos jurídicos que, teóricamente, permiten el cumplimiento de sus declaraciones. El control de constitucionalidad, y para el caso en estudio, el control de constitucionalidad concreto, es uno de aquellos mecanismos que defienden la hegemonía y la supremacía constitucional. El control de constitucionalidad concreto, es una herramienta apropiada para detectar normas inferiores en contradicción con las normas superiores; se activa ante la duda razonable de constitucionalidad de una norma jurídica, que esté siendo aplicada por la autoridad judicial ordinaria dentro de un caso concreto. Empero, la sustanciación de la consulta judicial de constitucionalidad de norma, exige que la causa concreta se suspenda por cuarenta y cinco días, sin resolver nada sobre lo principal (CR, Art. 428). En asuntos que litigan intereses particulares, suspender el trámite de la causa, sin resolver nada en el fondo, no representaría mayor problema, pero en las causas que ventilan derechos de personas y grupos de atención prioritaria (CR, Art. 35), cuyos bienes, por su trascendencia social, interesan a la causa pública, suspender el trámite del caso sin resolver nada de fondo, lesiona el principio de tutela judicial efectiva y del debido proceso en la garantía de defensa (CR, Arts: 75 y 75.7)

Scientific systems in Latin America: performance, networks, and collaborations with industry

In this paper, we use a combination of bibliometric, social network and econometric approaches to increase our knowledge of how research institutions interact with the private sector in Latin America (LA). We first study recent trends in scientific output and specialization. On average, LA countries have been reducing the gap with the world leading regions. They have also tended to specialize in fields related to economic activities based on natural resources, such as Agricultural and Plant and Animal Sciences. However, collaborations with the private sector remain scarce. In this paper, we have built scientific networks composed by what we define as Research Departments (RD). These RDs belong to universities, research institutes and government agencies. We model the intensity of collaboration of a RD with industry as a function of its size, previous performance, and its position in the LA and national scientific networks. Our results show that the RDs with higher diversity of research partners in their national scientific network work more intensively with industry. Additionally, collaborations with industry are influenced by previous interactions with the private sector