On the second largest eigenvalue of the signless Laplacian

Let $G$ be a graph of order $n,$ and let $q_{1}(G) \geq ...\geq q_{n}(G)$ be the eigenvalues of the $Q$-matrix of $G$, also known as the signless Laplacian of $G.$ In this paper we give a necessary and sufficient condition for the equality $q_{k}(G) =n-2,$ where $1<k\leq n.$ In particular, this result solves an open problem raised by Wang, Belardo, Huang and Borovicanin. We also show that [ q_{2}(G) \geq\delta(G)] and determine that equality holds if and only if $G$ is one of the following graphs: a star, a complete regular multipartite graph, the graph $K_{1,3,3},$ or a complete multipartite graph of the type $K_{1,...,1,2,...,2}$.Comment: This version fills a gap in one proof, noticed by Rundan Xin

Hybrid photonic entanglement: Realization, characterization and applications

We show that the quantum disentanglement eraser implemented on a two-photon system from parametric down-conversion is a general method to create hybrid photonic entanglement, namely the entanglement between different degrees of freedom of the photon pair. To demonstrate this, we generate and characterize a source with tunable degree of hybrid entanglement between two qubits, one encoded in the transverse momentum and position of a photon, and the other in the polarization of its partner. In addition, we show that a simple extension of our setup enables the generation of two-photon qubit-qudit hybrid entangled states. Finally, we discuss the advantages that this type of entanglement can bring for an optical quantum network.Comment: Published versio

New Strongly Coupled Sector at the Tevatron and the LHC

We examine the possibility that a new strong interaction is accessible to the Tevatron and the LHC. In an effective theory approach, we consider a scenario with a new color-octet interaction with strong couplings to the top quark, as well as the presence of a strongly coupled fourth-generation which could be responsible for electroweak symmetry breaking. We apply several constraints, including the ones from flavor physics. We study the phenomenology of the resulting parameter space at the Tevatron, focusing on the the forward-backward asymmetry in top pair production, as well as in the production of the fourth-generation quarks. We show that if the excess in the top production asymmetry is indeed the result of this new interaction, the Tevatron could see the first hints of the strongly coupled fourth-generation quarks. Finally, we show that the LHC with $\sqrt{s}=7~$TeV and $1~{\rm fb}^{-1}$ integrated luminosity should observe the production of fourth-generation quarks at a level at least one order of magnitude above the QCD prediction for the production of these states.Comment: 8 pages, 12 figure

Ações desenvolvidas para aumento da citologia oncótica em um posto de saúde de Barras-PI

De acordo com dados de 2008 da Organização Mundial de Saúde, o câncer do colo do útero é o 2º câncer mais comum em mulheres a nível mundial, com cerca de 500.000 novos casos e 250.000 mortes a cada ano. Plano de ação que teve como objetivo principal criar estratégias de melhoria da adesão das mulheres de 25-64 anos na realização do preventivo da área do posto de saúde da família do povoado da Formosa Barras/PI. Será realizada a busca dos pacientes já diagnosticados com neoplasia uterina, através dos agentes comunitários de saúde. Depois, será feita a orientação de consultas periódicas as demais mulheres do território, visando, assim a prevenção e o diagnóstico precoce. Espera-se com o plano de ação poderemos traçar estratégias para melhorar no atendimento das mulheres moradoras da zona rural de Barras, em relação a realização e cobertura do preventivo

Selenium accumulation in plants and implications for human health: a survey of molecular, biochemical, and ecological cues

2022 Summer.Includes bibliographical references.To view the abstract, please see the full text of the document

N-Relaxion: Large Field Excursions from a Few Site Relaxion Model

Relaxion models are an interesting new avenue to explain the radiative stability of the Standard Model scalar sector. They require very large field excursions, which are difficult to generate in a consistent UV completion and to reconcile with the compact field space of the relaxion. We propose an N-site model which naturally generates the large decay constant needed to address these issues. Our model offers distinct advantages with respect to previous proposals: the construction involves non-abelian fields, allowing for controlled high energy behaviour and more model building possibilities, both in particle physics and inflationary models, and also admits a continuum limit when the number of sites is large, which may be interpreted as a warped extra dimension.Comment: 7 pages, 2 figures; v2: version to appear in PR