Channeling 5-min photospheric oscillations into the solar outer atmosphere through small-scale vertical magnetic flux tubes

We report two-dimensional MHD simulations which demonstrate that photospheric 5-min oscillations can leak into the chromosphere inside small-scale vertical magnetic flux tubes. The results of our numerical experiments are compatible with those inferred from simultaneous spectropolarimetric observations of the photosphere and chromosphere obtained with the Tenerife Infrared Polarimeter (TIP) at 10830 A. We conclude that the efficiency of energy exchange by radiation in the solar photosphere can lead to a significant reduction of the cut-off frequency and may allow for the propagation of the 5 minutes waves vertically into the chromosphere.Comment: accepted by ApJ

One-dimensional metallic behavior of the stripe phase in La2−x_{2-x}Srx_xCuO4_4

Using an exact diagonalization method within the dynamical mean-field theory we study stripe phases in the two-dimensional Hubbard model. We find a crossover at doping $\delta\simeq 0.05$ from diagonal stripes to vertical site-centered stripes with populated domain walls, stable in a broad range of doping, $0.05<\delta<0.17$. The calculated chemical potential shift $\propto -\delta^2$ and the doping dependence of the magnetic incommensurability are in quantitative agreement with the experimental results for doped La$_{2-x}$Sr$_x$CuO$_4$. The electronic structure shows one-dimensional metallic behavior along the domain walls, and explains the suppression of spectral weight along the Brillouin zone diagonal.Comment: 4 pages, 4 figure

Acoustic-gravity wave propagation characteristics in 3D radiation hydrodynamic simulations of the solar atmosphere

There has been tremendous progress in the degree of realism of three-dimensional radiation magneto-hydrodynamic simulations of the solar atmosphere in the past decades. Four of the most frequently used numerical codes are Bifrost, CO5BOLD, MANCHA3D, and MURaM. Here we test and compare the wave propagation characteristics in model runs from these four codes by measuring the dispersion relation of acoustic-gravity waves at various heights. We find considerable differences between the various models. The height dependence of wave power, in particular of high-frequency waves, varies by up to two orders of magnitude between the models, and the phase difference spectra of several models show unexpected features, including $\pm180^\circ$ phase jumps.Comment: 19 pages, 15 figure

Vortex, skyrmion and elliptical domain wall textures in the two-dimensional Hubbard model

The spin and charge texture around doped holes in the two-dimensional Hubbard model is calculated within an unrestricted spin rotational invariant slave-boson approach. In the first part we examine in detail the spin structure around two holes doped in the half-filled system where we have studied cluster sizes up to 10 x 10. It turns out that the most stable configuration corresponds to a vortex-antivortex pair which has lower energy than the Neel-type bipolaron even when one takes the far field contribution into account. We also obtain skyrmions as local minima of the energy functional but with higher total energy than the vortex solutions. Additionally we have investigated the stability of elliptical domain walls for commensurate hole concentrations. We find that (i) these phases correspond to local minima of the energy functional only in case of partially filled walls, (ii) elliptical domain walls are only stable in the low doping regime.Comment: 7 pages, 6 figures, accepted for Phys. Rev.

Quantum Dot Potentials: Symanzik Scaling, Resurgent Expansions and Quantum Dynamics

This article is concerned with a special class of the ``double-well-like'' potentials that occur naturally in the analysis of finite quantum systems. Special attention is paid, in particular, to the so-called Fokker-Planck potential, which has a particular property: the perturbation series for the ground-state energy vanishes to all orders in the coupling parameter, but the actual ground-state energy is positive and dominated by instanton configurations of the form exp(-a/g), where a is the instanton action. The instanton effects are most naturally taken into account within the modified Bohr-Sommerfeld quantization conditions whose expansion leads to the generalized perturbative expansions (so-called resurgent expansions) for the energy values of the Fokker-Planck potential. Until now, these resurgent expansions have been mainly applied for small values of coupling parameter g, while much less attention has been paid to the strong-coupling regime. In this contribution, we compare the energy values, obtained by directly resumming generalized Bohr-Sommerfeld quantization conditions, to the strong-coupling expansion, for which we determine the first few expansion coefficients in powers of g^(-2/3). Detailed calculations are performed for a wide range of coupling parameters g and indicate a considerable overlap between the regions of validity of the weak-coupling resurgent series and of the strong-coupling expansion. Apart from the analysis of the energy spectrum of the Fokker-Planck Hamiltonian, we also briefly discuss the computation of its eigenfunctions. These eigenfunctions may be utilized for the numerical integration of the (single-particle) time-dependent Schroedinger equation and, hence, for studying the dynamical evolution of the wavepackets in the double-well-like potentials.Comment: 13 pages; RevTe

Extended Gaussian wave packet dynamics

We examine an extension to the theory of Gaussian wave packet dynamics in a one-dimensional potential by means of a sequence of time dependent displacement and squeezing transformations. Exact expressions for the quantum dynamics are found, and relationships are explored between the squeezed system, Gaussian wave packet dynamics, the time dependent harmonic oscillator, and wave packet dynamics in a Gauss-Hermite basis. Expressions are given for the matrix elements of the potential in some simple cases. Several examples are given, including the propagation of a non-Gaussian initial state in a Morse potential

Validação brasileira do Instrumento de Qualidade de Vida/espiritualidade, religião e crenças pessoais

OBJETIVO: Analisar propriedades psicométricas do Instrumento de Qualidade de Vida da Organização Mundial da Saúde - Módulo Espiritualidade, Religiosidade e Crenças Pessoais (WHOQOL-SRPB). MÉTODOS: O WHOQOL-SRPB, a Escala de Coping Religioso/Espiritual Abreviada (CRE-Breve), o WHOQOL-Breve e o BDI foram consecutivamente aplicados em amostra de conveniência de 404 pacientes e funcionários de hospital universitário e funcionários de universidade, em Porto Alegre, RS, entre 2006 e 2009. A amostra foi estratificada por sexo, idade, estado de saúde e religião/crença. O reteste dos dois primeiros instrumentos foi realizado com 54 participantes. Análises fatoriais exploratórias do WHOQOL-SRPB pelo método dos componentes principais foram realizadas sem delimitar o número de fatores, solicitando oito fatores e em conjunto com os itens do WHOQOL-Breve. RESULTADOS: O WHOQOL-SRPB em português brasileiro (Domínio SRPB-Geral) apresentou validade de construto, com validade discriminativa entre crentes de não-crentes (t = 7,40; p = 0,0001); validade relacionada ao critério concorrente, discriminando deprimidos de não-deprimidos (t = 5,03; p = 0,0001); validade convergente com o WHOQOL-Breve (com físico r = 0,18; psicológico r = 0,46; social r = 0,35; ambiental r = 0,29; global r = 0,23; p = 0,0001) e com o Domínio SRPB do WHOQOL-100 (r = 0,78; p = 0,0001); e validade convergente/discriminante com a Escala CRE-Breve (com CREpositivo r = 0,64; p = 0,0001/CREnegativo r = -0,03; p = 0,554). Observou-se excelente fidedignidade teste-reteste (t = 0,74; p = 0,463) e consistência interna (&#945; = 0,96; correlação intrafatorial 0,87 > r > 0,60, p = 0,0001). As análises fatoriais exploratórias realizadas corroboraram a estrutura de oito fatores do estudo multicêntrico do WHOQOL-SRPB. CONCLUSÕES: O WHOQOL-SRPB em português brasileiro apresentou boas qualidades psicométricas e uso válido e fidedigno para uso no Brasil. Sugerem-se novos estudos com populações específicas, como diferentes religiões, grupos culturais e/ou doenças.OBJETIVO: Analizar propiedades psicométricas del Instrumento de Calidad de Vida de la OMS - Módulo Espiritualidad, Religiosidad y Creencias Personales (WHOQOL-SRPB). MÉTODOS: El WHOQOL-SRPB, la Escala de Coping Religioso/Espiritual Abreviada (CRE-Breve), el WHOQOL-Breve y el BDI fueron consecutivamente aplicados en muestra de conveniencia de 404 pacientes y funcionarios de hospital universitario y funcionarios de universidad, en Porto Alegre, Sur de Brasil, entre 2006 y 2009. La muestra fue estratificada por sexo, edad, estado de salud y religión/creencia. La reevaluación de los dos primeros instrumentos fue realizada por 54 participantes. Análisis factoriales exploratorias del WHOQOL-SRPB por el método de los componentes principales fueron realizadas, sin delimitar el número de factores, solicitando ocho factores y en conjunto con los itens del WHOQOL-Breve. RESULTADOS: El WHOQOL-SRPB en portugués-brasileño (Dominio SRPB-General) presentó validez de constructo, con validez discriminativa entre creyentes de no creyentes (t=7,40; p=0,0001); validez relacionada con el criterio concurrente, discriminando deprimidos de no deprimidos (t=5,03; p=0,0001); validez convergente con el WHOQOL-Breve (con físico r=0,18; psicológico r=0,46; social r=0,35; ambiental r=0,29; global r=0,23; p=0,0001) y con el Dominio-SRPB del WHOQOL-100 (r=0,78; p=0,0001); y validez convergente/discriminante con la Escala CRE-Breve (con CRE positivo r=0,64; p=0,0001/CRE negativo r=-0,03; p=0,554). Se observó excelente fidedignidad test-retest (t=0,74; p=0,463) y consistencia interna (&#945;=0,96; correlación intrafactorial 0,87>r>0,60, p=0,0001). Los análisis factoriales exploratorios realizados corroboran la estructura de ocho factores de estudio multicéntrico del WHOQOL-SRPB. CONCLUSIONES: El WHOQOL-SRPB en portugués-brasileño presentó buenas cualidades psicométricas, siendo válido y fidedigno para uso en Brasil. Se sugieren nuevos estudios con poblaciones específicas, como diferentes religiones, grupos culturales y/o enfermedades.OBJECTIVE: To analyze the psychometric properties of the World Health Organization's Quality of Life Instrument - Spirituality, Religion and Personal Beliefs module (WHOQOL-SRPB). METHODS: The WHOQOL-SRPB, the Brief Spiritual/Religious Coping Scale (Brief-SRCOPE Scale), the WHOQOL-BREF and the Beck Depression Inventory (BDI) were consecutively applied in a convenience sample of 404 patients and workers of a university hospital and workers of a university, in the city of Porto Alegre, Southern Brazil, between 2006 and 2009. The sample was stratified by sex, age, health status and religion/belief. The retest of the two first instruments was conducted with 54 participants. Exploratory factorial analyses of the WHOQOL-SRPB with the method of main components were performed, without limiting the number of factors, and requiring eight factors concomitantly with the WHOQOL-BREF items. RESULTS: The Brazilian Portuguese version of the WHOQOL-SRPB (General SRPB-Domain) showed construct validity, with a discriminatory validity between believers and non-believers (t = 7.40; p = 0.0001); concurrent criterion-related validity, distinguishing depressed individuals from non-depressed ones (t = 5.03; p = 0.0001); convergent validity with the WHOQOL-BREF (physical r = 0.18; psychological r = 0.46; social r = 0.35; environmental r = 0.29; global r = 0.23; p = 0.0001) and with the SRPB-Domain of the WHOQOL-100 (r = 0.78; p = 0.0001); and convergent/discriminatory validity with the brief SRCOPE Scale (with positive SRCOPE r = 0.64; p = 0.0001/negative SRCOPE r = -0.03; p = 0.554). Excellent test-retest reliability (t = 0.74; p = 0.463) and internal consistency (&#945; = 0.96; intrafactorial correlation 0.87 > r > 0.60; p = 0.0001) were observed. The exploratory factorial analyses performed corroborated the eight-factor structure of the WHOQOL-SRPB multicenter study. CONCLUSIONS: The Brazilian Portuguese version of the WHOQOL-SRPB showed good psychometric qualities and use valid and reliable in Brazil. It is suggested that new studies be conducted with specific populations, such as different religions, cultural groups and/or diseases