Limitations on the superposition principle: superselection rules in non-relativistic quantum mechanics

The superposition principle is a very basic ingredient of quantum theory. What may come as a surprise to many students, and even to many practitioners of the quantum craft, is tha superposition has limitations imposed by certain requirements of the theory. The discussion of such limitations arising from the so-called superselection rules is the main purpose of this paper. Some of their principal consequences are also discussed. The univalence, mass and particle number superselection rules of non-relativistic quantum mechanics are also derived using rather simple methods.Comment: 22 pages, no figure

Dripping Faucet Dynamics Clarified by an Improved Mass-Spring Model

An improved mass-spring model for a dripping faucet is presented. The model is constructed based on the numerical results which we recently obtained from fluid dynamical calculations. Both the fluid dynamical calculations and the present mass-spring model exhibit a variety of complex behavior including transition to chaos in good agreement with experiments. Further, the mass-spring model reveals fundamental dynamics inherent in the dripping faucet system.Comment: 17 pages, 17 figure

Density functional electronic spectrum of the CuO−6−10Cu O_{-6}^{-10} cluster and possible local Jahn-Teller distorsions in the La-Ba-Cu-O superconductor

We present a density functional theory (DFT) calculation in the generalized gradient approximation to study the possibility for the existence of Jahn-Teller (JT) or pseudo Jahn-Teller (PJT) type local distortions in the La-Ba-Cu-O superconducting system. We performed the calculation and correspondingly group theory classification of the electronic ground state of the CuO${_{6}}^{-10}$ elongated octahedra cluster, immersed in a background simulating the superconductor. Part of the motivation to do this study is that the origin of the apical deformation of the CuO${_{6}}^{-10}$ cluster is not due to a pure JT effect, having therefore a non {\it a priori} condition to remove the degeneracy of the electronic ground state of the parent regular octahedron. We present a comparative analysis of the symmetry classified electron spectrum with previously reported results using unrestricted Hartree-Fock calculations (UHF). Both the DFT and UHF calculations produced a non degenerate electronic ground state, not having therefore the necessary condition for a pure JT effect. However, the appearance of a degenerate E$_{g}$ state near to the highest occupied molecular orbital in the DFT calculation, suggests the possibility for a PJT effect responsible for a local distortion of the oxidized CuO$_{6}^{-9}$ cluster.Comment: 12 pages, 3 figures, submitted to International Journal of Modern Physics B (IJMPB

Dimensionalities of Weak Solutions in Hydrogenic Systems

A close inspection on the 3D hydrogen atom Hamiltonian revealed formal eigenvectors often discarded in the literature. Although not in its domain, such eigenvectors belong to the Hilbert space, and so their time evolution is well defined. They are then related to the 1D and 2D hydrogen atoms and it is numerically found that they have continuous components, so that ionization can take place

Pashto Border Literature as Geopolitical Knowledge

In this article I read a selection of Pashto literatures as critical thought about geopolitics. Drawing on Michael Shapiro’s concept of aesthetic subjects, as well as on border theory, I argue that the authors, the content, and the literary networks of these works all comment on global relations of power, ranging from the local bordering effects of geopolitics, to systems of knowledge embedded in the spatiality and temporality of empire. I argue that past and current imperial processes have led to fragmenting effects in Afghan society, and literature both reflects and analyzes this. Beyond that, I argue—through the examples of authors’ lives as well as their work—that literary activity in Pashto has actively negotiated such processes throughout its history, and offers strategies for countervailing notions of global connectivity in action as well as thought. The decentralized and multiperspective images of life in these works sit in counterpoint not only to the systems-oriented views that drive military and other policy in Afghanistan during the ongoing US moment, but also to universalist perspectives upon which disciplines like world history and geopolitics traditionally rely. Additionally, though, Pashto literary networks themselves also produce alternative structures. This contributes to the aesthetic turn in IR by arguing that it is not only the aesthetic vision in works that challenges dominant knowledge; the shape of the Pashto literary formation itself, organic with its content, is an alternate form of knowledge-in-practice about the contemporary world

The one dimensional Hydrogen atom revisited

The one dimensional Schroedinger hydrogen atom is an interesting mathematical and physical problem to study bound states, eigenfunctions and quantum degeneracy issues. This 1D physical system gave rise to some intriguing controversy over more than four decades. Presently, still no definite consensus seems to have been reached. We reanalyzed this apparently controversial problem, approaching it from a Fourier transform representation method combined with some fundamental (basic) ideas found in self-adjoint extensions of symmetric operators. In disagreement with some previous claims, we found that the complete Balmer energy spectrum is obtained together with an odd parity set of eigenfunctions. Closed form solutions in both coordinate and momentum spaces were obtained. No twofold degeneracy was observed as predicted by the degeneracy theorem in one dimension, though it does not necessarily have to hold for potentials with singularities. No ground state with infinite energy exists since the corresponding eigenfunction does not satisfy the Schroedinger equation at the origin.Comment: Accepted for publication in the Canadian Journal of Physics, July 28th, 200

Costos y viabilidad económica de la producción y comercialización de la conserva de trucha (Oncorhynchus mykiss) en escabeche

Puno is the first rainbow trout producing region in Peru. The objective of the study was to study the feasibility of giving added value to trout. The cost analysis and financial viability of the production of six types of canned pickled trout preserves were considered. The fillets were obtained from trout fed with three commercial foods (Salmofood®, Naltech® and Tomasino®) and the preserves had two presentations (can vs. glass). The production costs were calculated through a documented record of data at market prices. The general theory of production costs was applied and through the cash flow financial tool the profitability indicators were found. The financial net present value (NPVf) was positive for all six presentations. The internal rate of return (IRR), both for canning (34.5, 37.5 and 42.8%) and for glass canning (34.7, 38.2 and 44.3%) was higher than the opportunity cost of capital (COK) and in both cases, the benefit-cost ratio (B/C) was similar and greater than one (1.05, 1.06 and 1.07) for the three commercial foods, respectively. The capital recovery period was between 5 and 6 years for the two types of preserves. In conclusion, the pickled trout canning project is profitable and, therefore, its investment is recommended to contribute to the sustainability of production and improve the income of producers in the region.Puno es la primera región productora de truchas arcoíris en el Perú. El estudio tuvo como objetivo estudiar la factibilidad de dar valor agregado a la trucha. Se consideró el análisis de costos y la viabilidad financiera de la producción de seis tipos de conservas de trucha en escabeche. Los filetes fueron obtenidos de truchas alimentadas con tres alimentos comerciales (Salmofood®, Naltech® y Tomasino®) y las conservas tuvieron dos presentaciones (lata vs. vidrio). Los costos de producción se calcularon mediante un registro documentado de datos a precios de mercado. Se aplicó la teoría general de costos de producción y mediante la herramienta financiera de flujo de caja se hallaron los indicadores de rentabilidad. El valor actual neto financiero (VANf) fue positivo para las seis presentaciones. La tasa interna de retorno (TIR), tanto para la conserva de lata (34.5, 37.5 y 42.8%) como para la conserva en vidrio (34.7, 38.2 y 44.3%) fue mayor al costo de oportunidad del capital (COK) y en ambos casos la ratio beneficio-costo (B/C) fue similar y mayor a uno (1.05, 1.06 y 1.07) para los tres alimentos comerciales, respectivamente. El periodo de recuperación del capital estuvo entre 5 y 6 años para los dos tipos de conservas. En conclusión, el proyecto de elaboración de conservas de trucha en escabeche es rentable y, por tanto, es recomendable su inversión para contribuir con la sostenibilidad de la producción y mejorar los ingresos de los productores de la región

Phenomenological and microscopic cluster models I. The geometric mapping

The geometrical mapping of algebraic nuclear cluster models is investigated within the coherent state formalism. Two models are considered: the Semimicroscopic Algebraic Cluster Model (SACM) and the Phenomenological Algebraic Cluster Model (PACM), which is a special limit of the SACM. The SACM strictly observes the Pauli exclusion principle while the PACM does not. The discussion of the SACM is adapted to the coherent state formalism by introducing the new SO(3) dynamical symmetry limit and third-order interaction terms in the Hamiltonian. The potential energy surface is constructed in both models and it is found that the effects of the Pauli principle can be simulated by higher-order interaction terms in the PACM. The present study is also meant to serve as a starting point for investigating phase transitions in the two algebraic cluster models.Comment: 13 pages, 0 figures, part one of a two part wor

Quantum oscillator as 1D anyon

It is shown that in one spatial dimension the quantum oscillator is dual to the charged particle situated in the field described by the superposition of Coulomb and Calogero-Sutherland potentials.Comment: 9 pages, LaTe

Forest hydrology in Chile: Past, present, and future

This paper reviews the current knowledge of hydrological processes in Chilean temperate forests which extend along western South America from latitude 29° S to 56 ° S. This geographic region includes a diverse range of natural and planted forests and a broad sweep of vegetation, edaphic, topographic, geologic, and climatic settings which create a unique natural laboratory. Many local communities, endangered freshwater ecosystems, and downstream economic activities in Chile rely on water flows from forested catchments. This review aims to (i) provide a comprehensive overview of Chilean forest hydrology, to (ii) review prior research in forest hydrology in Chile, and to (iii) identify knowledge gaps and provide a vision for future research on forest hydrology in Chile. We reviewed the relation between native forests, commercial plantations, and other land uses on water yield and water quality from the plot to the catchment scale. Much of the global understanding of forests and their relationship with the water cycle is in line with the findings of the studies reviewed here. Streamflow from forested catchments increases after timber harvesting, native forests appear to use less water than plantations, and streams draining native forest yield less sediment than streams draining plantations or grassland/shrublands. We identified 20 key knowledge gaps such as forest groundwater systems, soil–plant-atmosphere interactions, native forest hydrology, and the effect of forest management and restoration on hydrology. Also, we found a paucity of research in the northern geographic areas and forest types (35-36 ° S); most forest hydrology studies in Chile (56 %) have been conducted in the southern area (Los Rios Region around 39-40 ° S). There is limited knowledge of the geology and soils in many forested areas and how surface and groundwater are affected by changes in land cover. There is an opportunity to advance our understanding using process-based investigations linking field studies and modeling. Through the establishment of a forest hydrology science “society” to coordinate efforts, regional and national-scale land use planning might be supported. Our review ends with a vision to advance a cross-scale collaborative effort to use new nation-wide catchment-scale networks Long-term Ecosystem Research (LTER) sites, to promote common and complementary techniques in these studies, and to conduct transdisciplinary research to advance sound and integrated planning of forest lands in Chile