Bilinear and quadratic Hamiltonians in two-mode cavity quantum electrodynamics

In this work we show how to engineer bilinear and quadratic Hamiltonians in cavity quantum electrodynamics (QED) through the interaction of a single driven two-level atom with cavity modes. The validity of the engineered Hamiltonians is numerically analyzed even considering the effects of both dissipative mechanisms, the cavity field and the atom. The present scheme can be used, in both optical and microwave regimes, for quantum state preparation, the implementation of quantum logical operations, and fundamental tests of quantum theory.Comment: 11 pages, 3 figure

Nonadiabatic coherent evolution of two-level systems under spontaneous decay

In this paper we extend current perspectives in engineering reservoirs by producing a time-dependent master equation leading to a nonstationary superposition equilibrium state that can be nonadiabatically controlled by the system-reservoir parameters. Working with an ion trapped inside a nonindeal cavity we first engineer effective Hamiltonians that couple the electronic states of the ion with the cavity mode. Subsequently, two classes of decoherence-free evolution of the superposition of the ground and decaying excited levels are achieved: those with time-dependent azimuthal or polar angle. As an application, we generalise the purpose of an earlier study [Phys. Rev. Lett. 96, 150403 (2006)], showing how to observe the geometric phases acquired by the protected nonstationary states even under a nonadiabatic evolution.Comment: 5 pages, no figure

Accelerating networks

Evolving out-of-equilibrium networks have been under intense scrutiny recently. In many real-world settings the number of links added per new node is not constant but depends on the time at which the node is introduced in the system. This simple idea gives rise to the concept of accelerating networks, for which we review an existing definition and -- after finding it somewhat constrictive -- offer a new definition. The new definition provided here views network acceleration as a time dependent property of a given system, as opposed to being a property of the specific algorithm applied to grow the network. The defnition also covers both unweighted and weighted networks. As time-stamped network data becomes increasingly available, the proposed measures may be easily carried out on empirical datasets. As a simple case study we apply the concepts to study the evolution of three different instances of Wikipedia, namely, those in English, German, and Japanese, and find that the networks undergo different acceleration regimes in their evolution.Comment: 12 pages, 8 figure

Research on Long-Term Care Homes for Older People in Brazil: Protocol for Scoping Review

LOTUS CONSORTIUM - Improving care in Long-term Care Institutions in Brazil and Europe through Collaboration and ResearchBackground The fast growth of the ageing population in low and middle-income countries, such as Brazil, has allowed little time for social and health care systems to adapt. As the care needs for the most vulnerable and frail older people become increasingly complex, services and governments need to ensure that long term care homes deliver high-quality and evidence-based care to meet their healthcare needs. Aim To examine and map the range of research undertaken in Brazil regarding care homes published in peer reviewed journals. Method This scoping review will consider all relevant peer-reviewed primary studies fully or partly conducted in Brazilian care homes including those which consider workforce (for example, e.g. healthcare professionals, care staff, and management level staff) and care home residents (older people aged 60 years and above), using empirical and original research focused on any health related topic. The searches will be conducted using bibliographic databases (MEDLINE, EMBASE, LILACS and Google Scholar) and manual searching of the reference lists of relevant studies published in English, Portuguese or Spanish from inception up to 2018. Two authors will independently screen each document by title and abstract against the eligibility criteria. In case of disagreement, a third reviewer will be consulted. Data from the included studies will be extracted and reported using tables, graphs, and narrative accounts using elements of content analysis. The Mixed Methods Appraisal Tool will be used to appraise the methodological quality of the included studies

Structural constraints in complex networks

We present a link rewiring mechanism to produce surrogates of a network where both the degree distribution and the rich--club connectivity are preserved. We consider three real networks, the AS--Internet, the protein interaction and the scientific collaboration. We show that for a given degree distribution, the rich--club connectivity is sensitive to the degree--degree correlation, and on the other hand the degree--degree correlation is constrained by the rich--club connectivity. In particular, in the case of the Internet, the assortative coefficient is always negative and a minor change in its value can reverse the network's rich--club structure completely; while fixing the degree distribution and the rich--club connectivity restricts the assortative coefficient to such a narrow range, that a reasonable model of the Internet can be produced by considering mainly the degree distribution and the rich--club connectivity. We also comment on the suitability of using the maximal random network as a null model to assess the rich--club connectivity in real networks.Comment: To appear in New Journal of Physics (www.njp.org

Fragipãs e Duripãs: estruturas pedogenéticas ou sedimentares?

Os minerais pesados podem ser utilizados como indicadores pedogênicos, em alguns casos pode solucionar problemas importantes. Nos Tabuleiros Costeiros do Litoral Norte da Bahia materiais de origem sedimentar têm sido comumente confundidos com duripãs e fragipãs, por isso foram realizadas análises de minerais pesados em litofácies e solos do Grupo Barreiras com o intuito de contribuir para a resolução do problema. O estudo mostra que os minerais pesados presentes em estruturas associadas (?pãs?) e nas diferentes fácies do Grupo Barreiras são praticamente os mesmos, indicando o elo mineralógico. Além disso, a presença de minerais pesados instáveis como a biotita, além de outros pouco estáveis como granadas nas estruturas associadas indicam que são de origem sedimentar, sendo enquadrados como arenitos lamosos maciços

Intramural Vesical Leiomyoma in a Patient with a Pelvic Fibrous Tumour - Case Report

Introdução: O leiomioma vesical é um tumor benigno raro que representa,aproximadamente, 0,5% do total de neoplasias da bexiga. É frequentemente um achado imagiológico, sendo a sua localização e dimensões determinantes no desenvolvimento de sintomatologia e no tipo de procedimento a efectuar. Caso Clínico: Reporta-se o caso de um doente com queixas urinárias de disúria, polaquiúria e esforço miccional, inicialmente interpretadas como HBP. A investigação diagnóstica culminou com a enucleação de uma volumosa massa intramural da bexiga, com diagnóstico histológico de leiomioma, num doente com antecedentes de doença de Madelung e excisão prévia de um tumor fibroso paravesical. Discussão: O leiomioma vesical, embora apresentando características imagiológicas típicas, deve ser sempre biopsado para confirmação histológica da sua etiologia. O tumor fibroso pélvico apresenta sempre indicação cirúrgica pois, numa minoria de casos, pode apresentar comportamento agressivo com infiltração dos órgãos adjacentes

Decoherence-free evolution of time-dependent superposition states of two-level systems and thermal effects

In this paper we detail some results advanced in a recent letter [Prado et al., Phys. Rev. Lett. 102 073008 (2009)] showing how to engineer reservoirs for two-level systems at absolute zero by means of a time-dependent master equation leading to a nonstationary superposition equilibrium state. We also present a general recipe showing how to build nonadiabatic coherent evolutions of a fermionic system interacting with a bosonic mode and investigate the influence of thermal reservoirs at finite temperature on the fidelity of the protected superposition state. Our analytical results are supported by numerical analysis of the full Hamiltonian model.Comment: 7 pages, 4 figure

Nonlinear response of dense colloidal suspensions under oscillatory shear: Mode-coupling theory and FT-rheology experiments

Using a combination of theory, experiment and simulation we investigate the nonlinear response of dense colloidal suspensions to large amplitude oscillatory shear flow. The time-dependent stress response is calculated using a recently developed schematic mode-coupling-type theory describing colloidal suspensions under externally applied flow. For finite strain amplitudes the theory generates a nonlinear response, characterized by significant higher harmonic contributions. An important feature of the theory is the prediction of an ideal glass transition at sufficiently strong coupling, which is accompanied by the discontinuous appearance of a dynamic yield stress. For the oscillatory shear flow under consideration we find that the yield stress plays an important role in determining the non linearity of the time-dependent stress response. Our theoretical findings are strongly supported by both large amplitude oscillatory (LAOS) experiments (with FT-rheology analysis) on suspensions of thermosensitive core-shell particles dispersed in water and Brownian dynamics simulations performed on a two-dimensional binary hard-disc mixture. In particular, theory predicts nontrivial values of the exponents governing the final decay of the storage and loss moduli as a function of strain amplitude which are in excellent agreement with both simulation and experiment. A consistent set of parameters in the presented schematic model achieves to jointly describe linear moduli, nonlinear flow curves and large amplitude oscillatory spectroscopy