Socialización de experiencias de educación a nivel nacional de los departamentos y facultades de Ciencias básicas Bogotá-Colombia

La Universidad Manuela Beltrán buscó generar un espacio de socialización de experiencias de Educación en Ciencias Básicas, desde la formación científica, promoviendo la construcción de conocimiento, la reflexión continua y el diálogo entre saberes y prácticas, conducentes a la planificación de acciones al interior de las instituciones educativas que trasciendan al interior del aula. Se recibieron, analizaron y clasificaron por línea temáticas, sesenta y seis ponencias a nivel nacional. Con ello, se presenta así, una sistematización de con el objetivo de socializar a la comunidad académica los aspectos más relevantes de esta experiencia. Además de ofrecer como resultado los aprendizajes y parte de los análisis de las ponencias recibidas en el marco de este evento

The ππ→πγ⋆\pi\pi\to\pi\gamma^\star amplitude and the resonant ρ→πγ⋆\rho\to\pi\gamma^\star transition from lattice QCD

We present a determination of the $P$-wave $\pi\pi\to\pi\gamma^\star$ transition amplitude from lattice quantum chromodynamics. Matrix elements of the vector current in a finite-volume are extracted from three-point correlation functions, and from these we determine the infinite-volume amplitude using a generalization of the Lellouch-L\"uscher formalism. We determine the amplitude for a range of discrete values of the $\pi\pi$ energy and virtuality of the photon, and observe the expected dynamical enhancement due to the $\rho$ resonance. Describing the energy dependence of the amplitude, we are able to analytically continue into the complex energy plane and from the residue at the $\rho$ pole extract the $\rho\to \pi \gamma^\star$ transition form factor. This calculation, at $m_\pi\approx 400$ MeV, is the first to determine the form factor of an unstable hadron within a first principles approach to QCD.Comment: 20 pages, 16 figures, 3 table

Consistency Checks For Two-Body Finite-Volume Matrix Elements: Conserved Currents and Bound States

We present a model-independent framework to determine finite-volume corrections of matrix elements of spatially separated current-current operators. We define these matrix elements in terms of Compton-like amplitudes, i.e., amplitudes coupling single-particle states via two current insertions. We show that the infrared behavior of these matrix elements is dominated by the single-particle pole, which is approximated by the elastic form factors of the lowest-lying hadron. Therefore, given lattice data on the relevant elastic form factors, the finite-volume effects can be estimated nonperturbatively and without recourse to effective field theories. For illustration purposes, we investigate the implications of the proposed formalism for a class of scalar theories in two and four dimensions

A model-independent framework for determining finite-volume effects of spatially nonlocal operators

We present a model-independent framework to determine finite-volume corrections of matrix elements of spatially-separated current-current operators. We define these matrix elements in terms of Compton-like amplitudes, i.e. amplitudes coupling single-particle states via two current insertions. We show that the infrared behavior of these matrix elements is dominated by the single-particle pole, which is approximated by the elastic form factors of the lowest-lying hadron. Therefore, given lattice data on the relevant elastic form factors, the finite-volume effects can be estimated non-perturbatively and without recourse to effective field theories. For illustration purposes, we investigate the implications of the proposed formalism for a class of scalar theories in two and four dimensions.Comment: 15 pages, 5 figure

Constraining 1 + → 2 Coupled-Channel Amplitudes in a Finite Volume

Whether one is interested in accessing the excited spectrum of hadrons or testing the standard model of particle physics, electroweak transition processes involving multihadron channels in the final state play an important role in a variety of experiments. Presently the primary theoretical tool with which one can study such reactions is lattice QCD, which is defined in a finite spacetime volume. In this work, we investigate the feasibility of implementing existing finite-volume formalism in realistic lattice QCD calculation of reactions in which a stable hadron can transition to one of several two-hadron channels under the action of an external current. We provide a conceptual description of the coupled-channel transition formalism, a practical road map for carrying out a calculation, and an illustration of the approach using synthetic data for two nontrivial resonant toy models. The results provide a proof of principle that such reactions can indeed be constrained using modern-day lattice QCD calculations, motivating explicit computation in the near future

National Incentive Programs for CSP – Lessons Learned

AbstractAcknowledging that Concentrated Solar Power (CSP) stands out among other renewable technologies for technical features such as dispatchability - through storage and hybridization - and its potential for higher macroeconomic impact on the local economy, national and regional governments have set up incentive programs to promote the development of large scale solar thermal plants in recent years. These support mechanisms have largely contributed to the rapid growth of the global market since 2007. While Spain and USA remain leaders, representing most of the current ∼2.5 GW in operation, other countries have emerged within a short time as very ambitious players.In our research, we reviewed some of the most relevant national incentive programs introduced worldwide: Spain, India, South Africa, Morocco and Australia. The paper will give an overview of the mechanics of the different markets, covering key aspects such as: capacity allocation, phases and timelines, qualification criteria, technical and financial requirements, local content requirements, etc, and how these elements affected competition, tariffs and the global outcome of the programs.The lessons learned from the analysis constitute a useful set of guidelines for policy makers and developers, and could contribute to the design of future effective support mechanisms that will pave the way for the further uptake of CSP technologies.The research presented in the paper has been undertaken in the framework of a technical assistance to the Ministry of New and Renewable Energy of India on the preparation of the Utility Scale Concentrated Solar Power Program

Constraining 1 + → 2 Coupled-Channel Amplitudes in a Finite Volume

Whether one is interested in accessing the excited spectrum of hadrons or testing the standard model of particle physics, electroweak transition processes involving multihadron channels in the final state play an important role in a variety of experiments. Presently the primary theoretical tool with which one can study such reactions is lattice QCD, which is defined in a finite spacetime volume. In this work, we investigate the feasibility of implementing existing finite-volume formalism in realistic lattice QCD calculation of reactions in which a stable hadron can transition to one of several two-hadron channels under the action of an external current. We provide a conceptual description of the coupled-channel transition formalism, a practical road map for carrying out a calculation, and an illustration of the approach using synthetic data for two nontrivial resonant toy models. The results provide a proof of principle that such reactions can indeed be constrained using modern-day lattice QCD calculations, motivating explicit computation in the near future

Radiative damping of standing acoustic waves in solar coronal loops

Context. A detailed understanding of the physical processes that determine the damping timescales of magneto-acoustic waves is essential to interpret diagnostic results from the application of solar magneto-seismology. Aims. The influence of the transition region and the importance of radiative emission, arising from equilibrium and non-equilibrium ionisation balances, for the damping timescale of the fundamental mode standing acoustic wave is investigated. Methods. An extensive numerical study, in the framework of the field-aligned hydrodynamic approximation, is carried out of the damping of the fundamental mode standing wave in a solar coronal loop, for a wide range of loop lengths and apex temperatures. Results. It was found that the radiative emission arising from a non-equilibrium ionisation balance will always act to reduce the damping timescale (in comparison to the equilibrium case) and may do so by up to ~10%. The physics of the transition region is most crucial in determining the magnitude of the reduction of the damping timescale when a non-equilibrium ionisation balance is properly accounted for. Conclusions. The methods of solar magneto-seismology, in particular the tools of coronal seismology, may be used to estimate loop lengths to a reasonable degree of accuracy, although estimates of the apex temperature are significantly less reliable, and one should use alternative (e.g. spectroscopic) diagnostics instead

Proximal methods for stationary mean field games with local couplings

© 2018 Society for Industrial and Applied Mathematics. We address the numerical approximation of mean field games with local couplings. For power-like Hamiltonians, we consider a stationary system and also a system involving density constraints modeling hard congestion effects. For finite difference discretization of the mean field game system developed in [Y. Achdou and I. Capuzzo-Dolcetta, SIAM J. Numer. Anal., 48 (2010), pp. 1136-1162], we follow a variational approach. We prove that the aforementioned schemes can be obtained as the optimality system of suitably defined optimization problems. In order to prove the existence of solutions of the scheme with a variational argument, monotonicity assumptions on the coupling term are not needed, which allows us to recover general existence results proved by Achdou and Capuzzo-Dolcetta. Next, assuming that the coupling term is nondecreasing, the variational problem is cast as a convex optimization problem, for which we study and compare several proximal-type methods. These algorithms have several interesting features, such as global convergence and stability with respect to the viscosity parameter, which can eventually be zero. We assess the performance of the methods via numerical experiments