Entanglement from density measurements: analytical density-functional for the entanglement of strongly correlated fermions

We derive an analytical density functional for the single-site entanglement of the one-dimensional homogeneous Hubbard model, by means of an approximation to the linear entropy. We show that this very simple density functional reproduces quantitatively the exact results. We then use this functional as input for a local density approximation to the single-site entanglement of inhomogeneous systems. We illustrate the power of this approach in a harmonically confined system, which could simulate recent experiments with ultracold atoms in optical lattices as well as in a superlattice and in an impurity system. The impressive quantitative agreement with numerical calculations -- which includes reproducing subtle signatures of the particle density stages -- shows that our density-functional can provide entanglement calculations for actual experiments via density measurements. Next we use our functional to calculate the entanglement in disordered systems. We find that, at contrast with the expectation that disorder destroys the entanglement, there exist regimes for which the entanglement remains almost unaffected by the presence of disordered impurities.Comment: 6 pages, 3 figure

Simple parametrization for the ground-state energy of the infinite Hubbard chain incorporating Mott physics, spin-dependent phenomena and spatial inhomogeneity

Simple analytical parametrizations for the ground-state energy of the one-dimensional repulsive Hubbard model are developed. The charge-dependence of the energy is parametrized using exact results extracted from the Bethe-Ansatz. The resulting parametrization is shown to be in better agreement with highly precise data obtained from fully numerical solution of the Bethe-Ansatz equations than previous expressions [Lima et al., Phys. Rev. Lett. 90, 146402 (2003)]. Unlike these earlier proposals, the present parametrization correctly predicts a positive Mott gap at half filling for any U>0. The construction is extended to spin-dependent phenomena by parametrizing the magnetization-dependence of the ground-state energy using further exact results and numerical benchmarking. Lastly, the parametrizations developed for the spatially uniform model are extended by means of a simple local-density-type approximation to spatially inhomogeneous models, e.g., in the presence of impurities, external fields or trapping potentials. Results are shown to be in excellent agreement with independent many-body calculations, at a fraction of the computational cost.Comment: New Journal of Physics, accepte

Indicadores de hábitos alimentares não saudáveis, concentração sérica das vitaminas B12, ácido fólico e a cognição em idosos de Florianópolis

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde, Programa de Pós-Graduação em Nutrição, Florianópolis, 2016.O envelhecimento está associado à redução das capacidades cognitivas. Os fatores ambientais de exposição como os hábitos alimentares não saudáveis e as concentrações séricas das vitaminas B12 e ácido fólico, podem, em parte, determinar as alterações cognitivas em idosos. Diante do exposto, a presente tese objetivou analisar a associação entre indicadores de hábitos alimentares não saudáveis e a cognição, assim como investigarse a combinação de diferentes concentrações séricas entre vitaminas B12 e do ácido fólico ésuperior ao usode indicadores bioquímicos separados,para o risco de provável déficit cognitivo em idosos. O estudo transversal avaliou dados da pesquisa epidemiológica de base populacional e domiciliar "Condições de saúde da população idosa do município de Florianópolis/SC: estudo de base populacional ? EpiFloripa Idoso" em sua segunda onda (2013-2014). A variável dependente foi à cognição investigada pelo Mini-Exame do Estado Mental (MEEM). As variáveis independentes foram os indicadores de hábitos alimentares não saudáveis: frutas e hortaliças (= 4 porções ao dia); peixe (Abstract : Ageing is associated with lower cognitive capacity. Environmental exposure factors, such as unhealthy food habits and serum levels of vitamin B12 and folic acid, can partly determine cognitive changes in older adults. Given the above, the present thesis aimed to analyze the association between indicators of unhealthy food habits and cognition, and whether any combination of serum levels of vitamin B12 and folic acid is a better indicator of probable cognitive deficit in older adults than either vitamin alone. The cross-sectional study assessed data from the second wave (2013-2014) of the population- and household-based epidemiological survey called "Condições de saúde da população idosa do município de Florianópolis/SC: estudo de base populacional ? EpiFloripa Idoso" (Health condition of older adults from the municipality of Florianopolis/SC: population-based study ? EpiFloripa Older Adult). The dependent variable was cognition assessed by the Mini Mental State Examination (MMSE). The independent variables were the following indicators of unhealthy food habits: fruit and vegetable intake (= 4 servings per day); fish intake (< 1 serving per day); regular intake of fatty meats (yes/no); and serum levels of vitamin B12 and folic acid. In the first stage of the study, 1,197 older adults (778 women) aged more than 60 years were interviewed. Sample-weighted simple and linear regression analyses stratified by gender were conducted to analyze the relationships between unhealthy food habit indicators and cognition. Men and women had mean MMSE scores of 25.15 ± 5.56 and 24.26 ± 5.68, respectively (p=0.009). After adjustments, an independent association between inadequate fruit and vegetable intake (= 4 servings per day) and lower MMSE scores was found in women. Also in women the mean MMSE scores increased with daily fruit and vegetable intake frequency (p=0.001).No associations were found in men. The second stage of the study involved collecting blood samples from 590 older adults (386 women) to identify their serum levels of vitamin B12 and folic acid. Sample-weighted logistic regression analyzed the relationship between the biochemical variables and cognitive function. High serum folic acid protected against probable cognitive deficit (OR: 0.038; 95%CI 0.004; 0.374). When folic acid was kept as a continuous variable, increases in folic acid level reduced the risk of probable cognitive deficit (OR: 0.856; 95%CI 0.760; 0.964). The combination of excess serum folic acid and normal serum vitamin B12 did not protect against or increase the risk of probable cognitive deficit. The combination of B12 and folic acid was not a better predictor ofprobable cognitive deficit than either one, and did not predict probable cognitive deficit. The study women with inadequate fruit and vegetable intake according to the World Health Organization had lower cognitive scores. Regular intake of fruits, vegetables, and fish in detriment of fatty meat intake can be a viable strategy to preserve cognition during ageing and should be encouraged by public policies. Serum folic acid should remain within the normal range, avoiding an excess, since it was not possible to clarify the impact of the combination of high folic acid and low vitamin B12 on the cognitive function of these older adults

Sistema de cadastro de publicações para homepage da Embrapa Pecuária Sul: manual do usuário.

Acesso ao sistema; Operacionalização do sistema; Menu cadastro de formato/série; Menu cadastro de publicação; Menu sair do sistema.bitstream/item/63880/1/DT-63.pd

Effect of spatial inhomogeneity on the mapping between strongly interacting fermions and weakly interacting spins

A combined analytical and numerical study is performed of the mapping between strongly interacting fermions and weakly interacting spins, in the framework of the Hubbard, t-J and Heisenberg models. While for spatially homogeneous models in the thermodynamic limit the mapping is thoroughly understood, we here focus on aspects that become relevant in spatially inhomogeneous situations, such as the effect of boundaries, impurities, superlattices and interfaces. We consider parameter regimes that are relevant for traditional applications of these models, such as electrons in cuprates and manganites, and for more recent applications to atoms in optical lattices. The rate of the mapping as a function of the interaction strength is determined from the Bethe-Ansatz for infinite systems and from numerical diagonalization for finite systems. We show analytically that if translational symmetry is broken through the presence of impurities, the mapping persists and is, in a certain sense, as local as possible, provided the spin-spin interaction between two sites of the Heisenberg model is calculated from the harmonic mean of the onsite Coulomb interaction on adjacent sites of the Hubbard model. Numerical calculations corroborate these findings also in interfaces and superlattices, where analytical calculations are more complicated.Comment: 7 pages, 6 figure

Sistema de cadastro de eventos para homepage da Embrapa Pecuária Sul: manual do usuário.

Acesso ao sistema; Operacionalização do sistema; menu cadastro de eventos; Menu cadastro de arquivos para eventos; Menu sair do sistema.bitstream/item/63882/1/DT-62.pd

Work statistics and Entanglement across the fermionic superfluid-insulator transition

Entanglement in many-body systems may display interesting signatures of quantum phase transitions and similar properties are starting to be encountered in the analysis of work fluctuations. Here, we consider the fermionic superfluid-to-insulator transition (SIT) and relate its entanglement properties with its work distribution statistics. The SIT is modeled by the attractive fermionic Hubbard model in the presence of randomly distributed impurities. The work distribution is calculated across two quench protocols, both triggering the SIT. In the first, the concentration of impurities is increased; in the second, the impurities' disorder strength is varied. Our results indicate that, the critical state that induces minimization of the entanglement also maximizes the average work. We demonstrate that, for this state, density fluctuations vanish at all orders, hence all central moments of the work probability distribution are exactly zero at criticality. For systems undergoing a precursor to the transition (short chains with finite impurity potential) numerical results confirm these predictions, with higher moments further from the ideal result. For both protocols, at criticality, the system absorbs the most energy with almost no penalty in terms of fluctuations: ultimately this feature could be used to implement a quantum critical battery. The effects of temperature on these signatures of critical behaviour are also investigated and shown to favor work extraction for high enough temperatures

QUALIDADE DO SONO DE UNIVERSITÁRIOS: ASSOCIAÇÃO COM O ESTADO NUTRICIONAL E HÁBITOS ALIMENTARES

Sleep is a physiological, cyclical state, determinant for health. The aim of this study was to identify the relationship between sleep quality, nutritional status and frequency of food consumption among undergraduate students at a public university in southwestern Bahia. The Pittsburgh Sleep Quality Index was used to assess sleep quality. The assessment of nutritional status was verified by the Body Mass Index (BMI) based on self-reported measures. The frequency of consumption of fresh / minimally processed, processed and ultra-processed foods was investigated using an adapted instrument. 122 students were evaluated, with an average age of 22.5 ± 4.03 years, with a predominance of females. Most academics had poor sleep quality. As for nutritional status, most were classified as eutrophic. Regarding the frequency of food consumption, beans and rice are regularly consumed by most students. The daily intake of fruits and vegetables was verified in less than 50% of the sample. On the other hand, there was a high frequency in the consumption of processed and ultra-processed products. Sleep quality was not associated with nutritional status and eating habits, although other studies have found these relationships.O sono é um estado fisiológico, cíclico, determinante para a saúde. O objetivo deste estudo foi identificar a relação entre qualidade do sono, estado nutricional e frequência do consumo alimentar dos estudantes de graduação de uma universidade pública do sudoeste da Bahia. Para avaliação da qualidade do sono foi utilizado o Índice de Qualidade do sono de Pittsburgh. A avaliação do estado nutricional foi verificada pelo Índice de Massa Corporal (IMC) a partir de medidas auto referidas. A frequência do consumo de alimentos in natura/minimamente processados, processados e ultra processados foi investigada por meio de instrumento adaptado. Foram avaliados 122 estudantes, com idade média de 22,5 ± 4,03 anos, prevalecendo o sexo feminino. A maioria dos acadêmicos teve má qualidade do sono. Quanto ao estado nutricional, foram classificados, na maioria, como eutróficos. Em relação à frequência de consumo alimentar, o feijão e o arroz são consumidos regularmente pela maioria dos estudantes. Já a ingestão diária de frutas, legumes e verduras foi verificada em menos de 50% da amostra. Em contrapartida, observou-se alta frequência no consumo de processados e ultraprocessados. A qualidade do sono não foi associada ao estado nutricional e aos hábitos alimentares, apesar de outros estudos encontrarem essas relações

Besnoitiose bovina: revisão de literatura

A besnoitiose bovina é causada pela Besnoitia besnoiti, um protozoário Apicomplexa formador de cistos e é caracterizada por sinais clínicos locais e sistêmicos de gravidade variável. Semelhante a outros apicomplexas, B. besnoiti tem um ciclo de vida heteroxênico, tendo os bovinos domésticos e selvagens como hospedeiros intermediários. O hospedeiro definitivo ainda não foi identificado, embora o papel do gato doméstico tenha sido sugerido para outras espécies de Besnoitia. O ciclo de vida completo ainda é desconhecido e as vias de transmissão não foram totalmente determinadas. Esta doença progride em duas fases sequenciais: uma fase aguda febril com edemas e desordens respiratórias, e uma fase crônica caracterizada pela presença de cistos nos tecidos subcutâneos e lesões cutâneas. A besnoitiose bovina foi previamente descrita na África, no Oriente Médio e na Europa, e atualmente é considerada uma doença emergente em países europeus, como a Espanha, Portugal, França, Itália e Alemanha. Uma série de testes de diagnóstico como citologia, histopatologia, sorologia e PCR estão disponíveis. Não existem medicamentos eficazes ou vacinas disponíveis atualmente