Density-functionals not based on the electron gas: Local-density approximation for a Luttinger liquid

By shifting the reference system for the local-density approximation (LDA) from the electron gas to other model systems one obtains a new class of density functionals, which by design account for the correlations present in the chosen reference system. This strategy is illustrated by constructing an explicit LDA for the one-dimensional Hubbard model. While the traditional {\it ab initio} LDA is based on a Fermi liquid (the electron gas), this one is based on a Luttinger liquid. First applications to inhomogeneous Hubbard models, including one containing a localized impurity, are reported.Comment: 4 pages, 4 figures (final version, contains additional applications and discussion; accepted by Phys. Rev. Lett.

Critical wave-packet dynamics in the power-law bond disordered Anderson Model

We investigate the wave-packet dynamics of the power-law bond disordered one-dimensional Anderson model with hopping amplitudes decreasing as $H_{nm}\propto |n-m|^{-\alpha}$. We consider the critical case ($\alpha=1$). Using an exact diagonalization scheme on finite chains, we compute the participation moments of all stationary energy eigenstates as well as the spreading of an initially localized wave-packet. The eigenstates multifractality is characterized by the set of fractal dimensions of the participation moments. The wave-packet shows a diffusive-like spread developing a power-law tail and achieves a stationary non-uniform profile after reflecting at the chain boundaries. As a consequence, the time-dependent participation moments exhibit two distinct scaling regimes. We formulate a finite-size scaling hypothesis for the participation moments relating their scaling exponents to the ones governing the return probability and wave-function power-law decays

Exact solution of A-D Temperley-Lieb Models

We solve for the spectrum of quantum spin chains based on representations of the Temperley-Lieb algebra associated with the quantum groups {\cal U}_q(X_n } for X_n = A_1,B_n,C_n$and$D_n$. We employ a generalization of the coordinate Bethe-Ansatz developed previously for the deformed biquadratic spin one chain. As expected, all these models have equivalent spectra, i.e. they differ only in the degeneracy of their eigenvalues. This is true for finite length and open boundary conditions. For periodic boundary conditions the spectra of the lower dimensional representations are containded entirely in the higher dimensional ones. The Bethe states are highest weight states of the quantum group, except for some states with energy zero

Eddington-Born-Infeld action for dark energy and dark matter

We argue that Einstein gravity coupled to a Born-Infeld theory provides an attractive candidate to represent dark matter and dark energy. For cosmological models, the Born-Infeld field has an equation of state which interpolates between matter, w=0 (small times), and a cosmological constant w=-1 (large times). On galactic scales, the Born-Infeld field predicts asymptotically flat rotation curves.Comment: A sign mistake in section on galactic scales is pointed out. This sign invalidates the content of that section. See comment on manuscrip

Adaptação de método para a extração de proteínas de sementes de cerejeira (Amburana cearensis (Fr.All.) A.C.Smith).

bitstream/CENARGEN/23201/1/cot064.pd

The anisotropic XY model on the inhomogeneous periodic chain

The static and dynamic properties of the anisotropic XY-model $(s=1/2)$ on the inhomogeneous periodic chain, composed of $N$ cells with $n$ different exchange interactions and magnetic moments, in a transverse field $h,$ are determined exactly at arbitrary temperatures. The properties are obtained by introducing the Jordan-Wigner fermionization and by reducing the problem to a diagonalization of a finite matrix of $nth$ order. The quantum transitions are determined exactly by analyzing, as a function of the field, the induced magnetization 1/n\sum_{m=1}^{n}\mu_{m}\left ($j$ denotes the cell, $m$ the site within the cell, $\mu_{m}$ the magnetic moment at site $m$ within the cell) and the spontaneous magnetization $1/n\sum_{m=1}^{n}\left< S_{j,m}^{x},\right>$ which is obtained from the correlations $\left< S_{j,m}^{x}S_{j+r,m}^{x}\right>$ for large spin separations. These results, which are obtained for infinite chains, correspond to an extension of the ones obtained by Tong and Zhong(\textit{Physica B} \textbf{304,}91 (2001)). The dynamic correlations, $\left< S_{j,m}^{z}(t)S_{j^{\prime},m^{\prime}}^{z}(0)\right>$, and the dynamic susceptibility, $\chi_{q}^{zz}(\omega),$ are also obtained at arbitrary temperatures. Explicit results are presented in the limit T=0, where the critical behaviour occurs, for the static susceptibility $\chi_{q}^{zz}(0)$ as a function of the transverse field $h$, and for the frequency dependency of dynamic susceptibility $\chi_{q}^{zz}(\omega)$.Comment: 33 pages, 13 figures, 01 table. Revised version (minor corrections) accepted for publiction in Phys. Rev.

Uso da compostagem em sistemas agrícolas orgânicos.

O que é compostagem?; O que é composto orgânico?; Os benefícios da matéria orgânica no solo; Condições básicas para a decomposição da matéria orgânica (curtida); Manejo da produção do composto orgânico; Dimensionamento de uma unidade de compostagem; Aplicação do composto orgânico no campo.bitstream/CNPAT-2010/9207/1/Dc-089.pd

Living with conduct problem youth: Family functioning and parental perceptions of their child

Parenting children with conduct problems (CP) is challenging, yet very little is known about the impact of the child’s behaviour on family functioning or how parents of children with CP perceive their child. The aim of this research was to examine whether families with children with CP and high vs. low levels of callous–unemotional traits (HCU vs. LCU) experience differences in family functioning and parental perceptions. One hundred and one parents/caregivers of boys aged 11–16 [Typically developing (TD) n = 31; CP/HCU n = 35; CP/LCU n = 35] completed the McMaster Family Assessment Device, measuring multiple domains of family functioning. Parents/caregivers also completed a written statement describing their child, used for qualitative analysis. Families with CP/HCU children had poorer affective involvement than TD (p = 0.00; d = − 1.17) and CP/LCU (p = 0.03; d = − 0.62) families. Families with CP/HCU children showed significantly poorer general family functioning (p = 0.04; d = − 0.63) and more poorly defined family roles (p = 0.005; d = − 0.82) than families with TD children. Qualitative analyses indicated that parents/caregivers of CP/HCU children characterised them as having a dichotomous personality and being superficially charming. CP/LCU children were characterised as cheeky and endearing, with parents reporting good rapport. Families with CP/HCU children presented with specific difficulties in affective involvement and parents described challenges which were in line with the child’s specific presentation of lack of empathy and shallow affect. These findings may be used to help clinicians identify targets for family interventions

Efeito do recipiente utilizado na formação de mudas no crescimento e desenvolvimento de plantas de cajueiro cultivadas sob irrigação.

Utilizado ate recentemente como o principal recipiente para a propagacao de mudas de cajueiro anao precoce no Brasil, o saco plastico vem, gradativamente, sendo substituido pelo tubete. (...)bitstream/CNPAT-2010/5449/1/Pa-072.pd