Third quantization: a general method to solve master equations for quadratic open Fermi systems

The Lindblad master equation for an arbitrary quadratic system of n fermions is solved explicitly in terms of diagonalization of a 4n x 4n matrix, provided that all Lindblad bath operators are linear in the fermionic variables. The method is applied to the explicit construction of non-equilibrium steady states and the calculation of asymptotic relaxation rates in the far from equilibrium problem of heat and spin transport in a nearest neighbor Heisenberg XY spin 1/2 chain in a transverse magnetic field.Comment: 24 pages, with 8 eps figures - few minor corrections to the published version, e.g. anti-symmetrizing the matrix given by eq. (27

Nonequilibrium dynamics of a stochastic model of anomalous heat transport

We study the dynamics of covariances in a chain of harmonic oscillators with conservative noise in contact with two stochastic Langevin heat baths. The noise amounts to random collisions between nearest-neighbour oscillators that exchange their momenta. In a recent paper, [S Lepri et al. J. Phys. A: Math. Theor. 42 (2009) 025001], we have studied the stationary state of this system with fixed boundary conditions, finding analytical exact expressions for the temperature profile and the heat current in the thermodynamic (continuum) limit. In this paper we extend the analysis to the evolution of the covariance matrix and to generic boundary conditions. Our main purpose is to construct a hydrodynamic description of the relaxation to the stationary state, starting from the exact equations governing the evolution of the correlation matrix. We identify and adiabatically eliminate the fast variables, arriving at a continuity equation for the temperature profile T(y,t), complemented by an ordinary equation that accounts for the evolution in the bulk. Altogether, we find that the evolution of T(y,t) is the result of fractional diffusion.Comment: Submitted to Journal of Physics A, Mathematical and Theoretica

Current in coherent quantum systems connected to mesoscopic Fermi reservoirs

We study particle current in a recently proposed model for coherent quantum transport. In this model, a system connected to mesoscopic Fermi reservoirs (meso-reservoir) is driven out of equilibrium by the action of super-reservoirs thermalized to prescribed temperatures and chemical potentials by a simple dissipative mechanism described by the Lindblad equation. We compare exact (numerical) results with theoretical expectations based on the Landauer formula

ANCESTRALIDADE, SOBRENOMES E DISCRIMINAÇÃO: EVIDÊNCIAS A PARTIR DO JOGO ALEMANHA 7X1 BRASIL

Este artigo analisa os mecanismos da discriminação com base na ancestralidade dos trabalhadores brasileiros. O estudo utiliza informações de sobrenomes para identificar grupos de ancestralidades e examina se houve discriminação em favor de indivíduos com ancestralidade germânica após a derrota da seleção brasileira de futebol na Copa do Mundo de 2014. Limitando a nossa análise nos trabalhadores que apenas entraram no mercado de trabalho formal em 2014, antes e depois do jogo em questão, estimamos regressões mincerianas com controles baseados na ancestralidade indicada pelos sobrenomes e modelos probit para a obtenção do primeiro emprego. Os resultados mostram que a vitória da Alemanha teve um impacto positivo nos salários dos trabalhadores com sobrenomes germânicos, mas também resultou em uma redução na probabilidade desses trabalhadores serem contratados. Foram observados impactos menores para trabalhadores com sobrenomes italianos, ibéricos e japoneses, com efeitos positivos para os primeiros e negativo para os japoneses. O estudo contribui para uma compreensão mais ampla dos efeitos econômicos de eventos socioculturais e se relaciona com pesquisas anteriores que exploram os impactos da ancestralidade nos salários e na probabilidade de contratação no mercado de trabalho

Yrast line for weakly interacting trapped bosons

We compute numerically the yrast line for harmonically trapped boson systems with a weak repulsive contact interaction, studying the transition to a vortex state as the angular momentum L increases and approaches N, the number of bosons. The L=N eigenstate is indeed dominated by particles with unit angular momentum, but the state has other significant components beyond the pure vortex configuration. There is a smooth crossover between low and high L with no indication of a quantum phase transition. Most strikingly, the energy and wave function appear to be analytical functions of L over the entire range 2 < L < N. We confirm the structure of low-L states proposed by Mottelson, as mainly single-particle excitations with two or three units of angular momentum.Comment: 9 pages, 3 EPS-figures, uses psfig.st

Minimal invasive surgery in craniostenosis

En el presente trabajo se describe la experiencia en craneoestenosis con cirugía mínimamente invasiva, evaluando el diseño y eficacia de un nuevo craneotomo en cadáveres así como su aplicación clínica en un caso de sinostósis sagital con instrumentación endoscópica. Este procedimiento es sin duda un gran recurso en el tratamiento de las craneoestenosis brindando los beneficios de la cirugía mínimamente invasiva, eliminando la necesidad de grandes incisiones, disminuyendo el sangrado quirúrgico, reduciendo estancia hospitalaria y disminuyendo la morbilidad operatoria In this paper, we describe the experience with the use of endoscopic craniofacial procedures, evaluating the design and the efficacy of a new craniotome in cadavers and his clinical application in a case of sagittal synostosis for an endoscopic assisted cranioplasty. This procedure is a great option in the treatment of craniosynostosis, giving the benefits of minimal invasive surgery and eliminating the needing of big incisions, long hospital stay and reducing the postoperative morbidit

Stochastic dynamics and control of a driven nonlinear spin chain: the role of Arnold diffusion

We study a chain of non-linear, interacting spins driven by a static and a time-dependent magnetic field. The aim is to identify the conditions for the locally and temporally controlled spin switching. Analytical and full numerical calculations show the possibility of stochastic control if the underlying semi-classical dynamics is chaotic. This is achievable by tuning the external field parameters according to the method described in this paper. We show analytically for a finite spin chain that Arnold diffusion is the underlying mechanism for the present stochastic control. Quantum mechanically we consider the regime where the classical dynamics is regular or chaotic. For the latter we utilize the random matrix theory. The efficiency and the stability of the non-equilibrium quantum spin-states are quantified by the time-dependence of the Bargmann angle related to the geometric phases of the states.Comment: Journal-ref: to appear in J.Phys.

Chaos and Complexity of quantum motion

The problem of characterizing complexity of quantum dynamics - in particular of locally interacting chains of quantum particles - will be reviewed and discussed from several different perspectives: (i) stability of motion against external perturbations and decoherence, (ii) efficiency of quantum simulation in terms of classical computation and entanglement production in operator spaces, (iii) quantum transport, relaxation to equilibrium and quantum mixing, and (iv) computation of quantum dynamical entropies. Discussions of all these criteria will be confronted with the established criteria of integrability or quantum chaos, and sometimes quite surprising conclusions are found. Some conjectures and interesting open problems in ergodic theory of the quantum many problem are suggested.Comment: 45 pages, 22 figures, final version, at press in J. Phys. A, special issue on Quantum Informatio

Investigative Ophthalmology &amp; Visual Science A Journal of Dosic and Clinical Research Articles Non-Fluorescent Dye Staining of Primate Blue Cones

The intravitreal injection in macaque retina of the fluorescent dye Procion yellow can selectively label a specific cone population whose eccentricity distribution and angular separation are consistent with those of the blue-sensitive cones of human and non-human primate retinas. Because at the concentrations used the dye is poorly visible in conventional light microscopy, fluorescence microscopy is required for the observation of the stained cones. In this paper we describe several alternative methods for the staining of blue cones in primate retina, staining that can be visualized in conventional light microscopy and, with some methods, electron microscopy. Invest Ophthalmol Vis Sci 24:1449-1455, 198