Progress in the mathematical theory of quantum disordered systems

We review recent progress in the mathematical theory of quantum disordered systems: the Anderson transition, including some joint work with Marchetti, the (quantum and classical) Edwards-Anderson (EA) spin-glass model and return to equilibrium for a class of spin-glass models, which includes the EA model initially in a very large transverse magnetic field. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4770066]

Nonlocal growth processes and conformal invariance

Up to now the raise-and-peel model was the single known example of a one-dimensional stochastic process where one can observe conformal invariance. The model has one parameter. Depending on its value one has a gapped phase, a critical point where one has conformal invariance, and a gapless phase with changing values of the dynamical critical exponent z. In this model, adsorption is local but desorption is not. The raise-and-strip model presented here, in which desorption is also nonlocal, has the same phase diagram. The critical exponents are different as are some physical properties of the model. Our study suggests the possible existence of a whole class of stochastic models in which one can observe conformal invariance.

Entanglement of excited states in critical spin chains

Renyi and von Neumann entropies quantifying the amount of entanglement in ground states of critical spin chains are known to satisfy a universal law which is given by the conformal field theory (CFT) describing their scaling regime. This law can be generalized to excitations described by primary fields in CFT, as was done by Alcaraz et al in 2011 (see reference [1], of which this work is a completion). An alternative derivation is presented, together with numerical verifications of our results in different models belonging to the c = 1, 1/2 universality classes. Oscillations of the Renyi entropy in excited states are also discussed.

Both the dorsal hippocampus and the dorsolateral striatum are needed for rat navigation in the Morris water maze

The multiple memory systems theory proposes that the hippocampus and the dorsolateral striatum are the core structures of the spatial/relational and stimulus-response (S-R) memory systems, respectively. This theory is supported by double dissociation studies showing that the spatial and cue (S-R) versions of the Morris water maze are impaired by lesions in the dorsal hippocarnpus and dorsal striatum, respectively. In the present study we further investigated whether adult male Wistar rats bearing double and bilateral electrolytic lesions in the dorsal hippocampus and dorsolateral striatum were as impaired as rats bearing single lesions in just one of these structures in learning both versions of the water maze. Such a prediction, based on the multiple memory systems theory, was not confirmed. Compared to the controls, the animals with double lesions exhibited no improvement at all in the spatial version and learned the cued version very slowly. These results suggest that, instead of independent systems competing for holding control over navigational behaviour, the hippocampus and dorsal striatum both play critical roles in navigation based on spatial or cue-based strategies. (C) 2011 Elsevier B.V. All rights reserved.

Um balanço de parte da teoria dos sistemas intencionais de Dennett

Dennett (1981/1987b) caracteriza sua abordagem do funcionamento dos termos intencionais (aqueles para as assim chamadas atitudes proposicionais) como um "behaviorismo lógico holista", ou versão holista de delineamentos conceituais traçados por Ryle (1949). Este artigo avalia algumas de suas possíveis contribuições e desvantagens para tais delineamentos, e algumas consequências para sua proposta de utilização destes termos em psicologia. Argumenta-se que a abordagem não se mostra mais plausível do que a de seu predecessor, caso a dimensão mentalista que lhe acrescenta seja equivocada, e que de fato este é o caso. Disso resulta que suas contribuições e proposta correlata devem ser entendidas com independência daquilo que tal dimensão implica. Uma alternativa não-mentalista, baseada no modelo selecionista de Skinner, para uma eventual adoção dos termos intencionais em psicologia, é brevemente discutida.

Desenvolvimento Sustentável: análise das relações interorganizacionais na indústria de celulose e papel

O trabalho apresenta os resultados da aplicação do modelo de sistematização do processo de análise das relações de influências entre os agentes públicos e privados na busca do desenvolvimento sustentável da Região do Alto Tietê, em particular, na indústria de celulose e papel da região. Para tanto, desenvolveu-se um referencial teórico ajustado com a dinâmica conflituosa entre os interesses econômicos, sociais e ambientais. A sustentação teórica foi alcançada com a composição das seguintes abordagens conceituais: Teoria dos Sistemas Abertos, Nova Economia Institucional e Organizações em Rede. A pesquisa-ação foi o método adotado para aprofundar o estudo das relações dos agentes envolvidos na indústria de celulose e papel do município de Suzano. A ilustração da aplicação do modelo, com os dados obtidos, serve para mostrar uma perspectiva mais analítica para o estudo das relações entre os agentes envolvidos em atividades econômicas, respeitando os preceitos do desenvolvimento sustentável.

Analytic perturbation theory for bound states in the transfer matrix spectrum of weakly correlated lattice ferromagnetic spin systems

We consider general d-dimensional lattice ferromagnetic spin systems with nearest neighbor interactions in the high temperature region ('beta' << 1). Each model is characterized by a single site apriori spin distribution taken to be even. We also take the parameter 'alfa' = ('S POT.4') - 3 '(S POT.2') POT.2' > 0, i.e. in the region which we call Gaussian subjugation, where ('S POT.K') denotes the kth moment of the apriori distribution. Associated with the model is a lattice quantum field theory known to contain a particle of asymptotic mass -ln 'beta' and a bound state below the two-particle threshold. We develop a 'beta' analytic perturbation theory for the binding energy of this bound state. As a key ingredient in obtaining our result we show that the Fourier transform of the two-point function is a meromorphic function, with a simple pole, in a suitable complex spectral parameter and the coefficients of its Laurent expansion are analytic in 'beta'.