Reduction of quantum noise in optical interferometers using squeezed light

We study the photon counting noise in optical interferometers used for gravitational wave detection. In order to reduce quantum noise a squeezed vacuum state is injected into the usually unused input port. Here, we specifically investigate the so called `dark port case', when the beam splitter is oriented close to 90{\deg} to the incoming laser beam, such that nearly all photons go to one output port of the interferometer, and only a small fraction of photons is seen in the other port (`dark port'). For this case it had been suggested that signal amplification is possible without concurrent noise amplification [R.Barak and Y.Ben-Aryeh, J.Opt.Soc.Am.B25(361)2008]. We show that by injection of a squeezed vacuum state into the second input port, counting noise is reduced for large values of the squeezing factor, however the signal is not amplified. Signal strength only depends on the intensity of the laser beam.Comment: 8 pages, 1 figur

Atributos químicos do solo após a deposição de resíduos vegetais e revegetação nas margens do Rio dos Macacos no Jardim Botânico do Rio de Janeiro.

Neste estudo foram avaliadas as características da fertilidade do solo sob o manejo da deposição de resíduos vegetais e revegetação de um trecho do rio dos macacos na área verde do Jardim Botânico do Rio de Janeiro. Os teores de C e N foram maiores nas áreas revegetadas. A adição de resíduos orgânicos promoveu o aumento de pH do solo. Os teores de Ca+2 foram superiores no composto vegetal e proporcionou incrementos significativos na área de deposição. Já em relação aos teores de Mg+2 e o H+Al, não houve diferenças significativas entre as áreas e o composto vegetal. Os valores para os teores de sódio foram maiores significativamente na área de mata secundária. Os teores de fósforo foram significativamente maiores nas áreas de deposição e revegetadas há 3 e 4 anos, o que evidencia a contribuição do composto vegetal para incrementar os valores para este elemento no solo. Concuiu-se que a deposição de resíduos vegetais no solo pode ser utilizada como fator que favorece a melhoria dos atributos químicos com aumento significativo da fertilidade e do condicionamento do solo

Determining R-parity violating parameters from neutrino and LHC data

In supersymmetric models neutrino data can be explained by R-parity violating operators which violate lepton number by one unit. The so called bilinear model can account for the observed neutrino data and predicts at the same time several decay properties of the lightest supersymmetric particle. In this paper we discuss the expected precision to determine these parameters by combining neutrino and LHC data and discuss the most important observables. We show that one can expect a rather accurate determination of the underlying R-parity parameters assuming mSUGRA relations between the R-parity conserving ones and discuss briefly also the general MSSM as well as the expected accuracies in case of a prospective e+ e- linear collider. An important observation is that several parameters can only be determined up to relative signs or more generally relative phases.Comment: 13 pages, 13 figure

Anomalous Higgs Couplings

We review the effects of new effective interactions on the Higgs boson phenomenology. New physics in the electroweak bosonic sector is expected to induce additional interactions between the Higgs doublet field and the electroweak gauge bosons leading to anomalous Higgs couplings as well as to anomalous gauge-boson self-interactions. Using a linearly realized $SU(2)_L \times U(1)_Y$ invariant effective Lagrangian to describe the bosonic sector of the Standard Model, we review the effects of the new effective interactions on the Higgs boson production rates and decay modes. We summarize the results from searches for the new Higgs signatures induced by the anomalous interactions in order to constrain the scale of new physics in particular at CERN LEP and Fermilab Te vatron colliders.Comment: 35 pages, latex using epsfig.sty psfig.sty and axodraw.sty, 16 postscript figure

Multicanonical Hybrid Monte Carlo: Boosting Simulations of Compact QED

We demonstrate that substantial progress can be achieved in the study of the phase structure of 4-dimensional compact QED by a joint use of hybrid Monte Carlo and multicanonical algorithms, through an efficient parallel implementation. This is borne out by the observation of considerable speedup of tunnelling between the metastable states, close to the phase transition, on the Wilson line. We estimate that the creation of adequate samples (with order 100 flip-flops) becomes a matter of half a year's runtime at 2 Gflops sustained performance for lattices of size up to 24^4.Comment: 15 pages, 8 figure

Association between community noise and children's cognitive and behavioral development: a prospective cohort study

BACKGROUND: Noise exposure has been associated with adverse cognitive and behavioral outcomes in children, but evidence on longitudinal associations between community noise and child development in low- and middle-income countries is rare. We investigated associations between community noise and behavioral and cognitive development in preschool children in Sao Paulo. METHODS: We linked child development data from the Sao Paulo Western Region Birth Cohort with average (Lden) and night-time (Lnight) community noise exposure at children's home, estimated by means of a land use regression model using various predictors (roads, schools, greenness, residential and informal settlements). Outcomes were the Strengths and Difficulties Questionnaire (SDQ) and Regional Project on Child Development Indicators (PRIDI) at 3 years of age and the Child Behavior Checklist (CBCL) and International Development and Early Learning Assessment (IDELA) at 6 years of age. We investigated the relationship between noise exposure and development using cross-sectional and longitudinal regression models. RESULTS: Data from 3385 children at 3 years of age and 1546 children at 6 years of age were analysed. Mean Lden and Lnight levels were 70.3 dB and 61.2 dB, respectively. In cross-sectional analyses a 10 dB increase of Lden above 70 dB was associated with a 32% increase in the odds of borderline or abnormal SDQ total difficulties score (OR = 1.32, 95% CI: 1.04; 1.68) and 0.72 standard deviation (SD) increase in the CBCL total problems z-score (95% CI: 0.55; 0.88). No cross-sectional association was found for cognitive development. In longitudinal analyses, each 10 dB increase was associated with a 0.52 SD increase in behavioral problems (95% CI: 0.28; 0.77) and a 0.27 SD decrease in cognition (95%-CI: 0.55; 0.00). Results for Lnight above 60 dB were similar. DISCUSSION: Our findings suggest that community noise exposure above Lden of 70 dB and Lnight of 60 dB may impair behavioral and cognitive development of preschool children

Noise Kernel in Stochastic Gravity and Stress Energy Bi-Tensor of Quantum Fields in Curved Spacetimes

The noise kernel is the vacuum expectation value of the (operator-valued) stress-energy bi-tensor which describes the fluctuations of a quantum field in curved spacetimes. It plays the role in stochastic semiclassical gravity based on the Einstein-Langevin equation similar to the expectation value of the stress-energy tensor in semiclassical gravity based on the semiclassical Einstein equation. According to the stochastic gravity program, this two point function (and by extension the higher order correlations in a hierarchy) of the stress energy tensor possesses precious statistical mechanical information of quantum fields in curved spacetime and, by the self-consistency required of Einstein's equation, provides a probe into the coherence properties of the gravity sector (as measured by the higher order correlation functions of gravitons) and the quantum nature of spacetime. It reflects the low and medium energy (referring to Planck energy as high energy) behavior of any viable theory of quantum gravity, including string theory. It is also useful for calculating quantum fluctuations of fields in modern theories of structure formation and for backreaction problems in cosmological and black holes spacetimes. We discuss the properties of this bi-tensor with the method of point-separation, and derive a regularized expression of the noise-kernel for a scalar field in general curved spacetimes. One collorary of our finding is that for a massless conformal field the trace of the noise kernel identically vanishes. We outline how the general framework and results derived here can be used for the calculation of noise kernels for Robertson-Walker and Schwarzschild spacetimes.Comment: 22 Pages, RevTeX; version accepted for publication in PR

Crescimento de plantas de mogno brasileiro (Swietenia Macrophylla king.) cultivadas em diferentes substratos no horto florestal do Jardim Botânico do Rio de Janeiro.

A demanda de mudas de plantas da Mata Atlântica supera a oferta no mercado brasileiro. A necessidade de substratos para germinação e desenvolvimento das plantas envolve grande volume de insumos ricos em matéria orgânica e nutriente que suprem necessidades físicas, químicas e biológicas dos vegetais. Os resíduos vegetais produzidos nos 57 ha do arboreto do Jardim Botânico do Rio de Janeiro apresentam elevados teores de nutrientes essenciais às plantas. Para êxito na produção de mudas de qualidade consideram-se características físicas e químicas do substrato, as quais conferem qualidades que permitem o desenvolvimento e proteção das raízes na fase de viveiro. As recomendações para manejo do mogno inclui que a regeneração deve ser estimulada de forma artificial devido pouca habilidade natural em se regenerar após desmatamento intenso. O mogno (Swietenia macrophylla King.) se encontra entre as espécies mais exploradas no setor madeireiro e está ameaçada de extinção, considerada madeira nobre entre as mais valiosas na Amazônia, pois possui diversas utilidades. O objetivo deste trabalho foi avaliar o desenvolvimento de plantas de mogno nativo do Brasil (Swietenia macrophylla King.) cultivado em diferentes substratos no horto florestal do Jardim Botânico do Rio de Janeiro

Produção de mudas de Schizolobium Parahyba (Vell.) blake cultivadas em diferentes substratos no horto florestal do Jardim Botânico do Rio de Janeiro.

Entre as diversas espécies florestais nativas de rápido crescimento, como possíveis fontes de madeira para reflorestamento, o guapuruvu (Shizolobium parahyba (Vell.) Blake) apresenta pouca exigência quanto à fertilidade do solo e encontra-se ao longo de todo Vale do Paraíba, onde as terras possuem baixo teor de nutrientes em consequência da exaustão de culturas na época colonial. Contudo nota-se melhoria no crescimento das plantas nos solos com boa fertilidade, profundos, úmidos e bem drenados. O conhecimento dos requerimentos nutricionais das espécies e respostas em relação aos substratos é fundamental para êxito na produção de mudas de qualidade. Quanto maior o conhecimento para produção de mudas melhor será a propagação para plantios e reflorestamento. O objetivo deste trabalho foi avaliar o desenvolvimento de plantas de guapuruvu (Shizolobium parahyba (Vell.) Blake) cultivados em diferentes substratos no horto florestal do Jardim Botânico do Rio de Janeiro