Nonviolation of Bell's Inequality in Translation Invariant Systems

The nature of quantum correlations in strongly correlated systems has been a subject of intense research. In particular, it has been realized that entanglement and quantum discord are present at quantum phase transitions and able to characterize it. Surprisingly, it has been shown for a number of different systems that qubit pairwise states, even when highly entangled, do not violate Bell's inequalities, being in this sense local. Here we show that such a local character of quantum correlations is in fact general for translation invariant systems and has its origins in the monogamy trade-off obeyed by tripartite Bell correlations. We illustrate this result in a quantum spin chain with a soft breaking of translation symmetry. In addition, we extend the monogamy inequality to the $N$-qubit scenario, showing that the bound increases with $N$ and providing examples of its saturation through uniformly generated random pure states.Comment: Published erratum added at the en

Overcoming ambiguities in classical and quantum correlation measures

We identify ambiguities in the available frameworks for defining quantum, classical, and total correlations as measured by discordlike quantifiers. More specifically, we determine situations for which either classical or quantum correlations are not uniquely defined due to degeneracies arising from the optimization procedure over the state space. In order to remove such degeneracies, we introduce a general approach where correlations are independently defined, escaping therefore from a degenerate subspace. As an illustration, we analyze the trace-norm geometric quantum discord for two-qubit Bell-diagonal states.Comment: 5 pages, 2 figures. v2: Minor corrections. Published versio

Geometric classical and total correlations via trace distance

We introduce the concepts of geometric classical and total correlations through Schatten 1-norm (trace norm), which is the only Schatten p-norm able to ensure a well-defined geometric measure of correlations. In particular, we derive the analytical expressions for the case of two-qubit Bell-diagonal states, discussing the superadditivity of geometric correlations. As an illustration, we compare our results with the entropic correlations, discussing both their hierarchy and monotonicity properties. Moreover, we apply the geometric correlations to investigate the ground state of spin chains in the thermodynamic limit. In contrast to the entropic quantifiers, we show that the classical correlation is the only source of 1-norm geometric correlation that is able to signaling an infinite-order quantum phase transition.Comment: v2: published versio

Operational Classification and Quantification of Multipartite Entangled States

We formalize and extend an operational multipartite entanglement measure introduced by T. R. Oliveira, G. Rigolin, and M. C. de Oliveira, Phys. Rev. A 73, 010305(R) (2006), through the generalization of global entanglement (GE) [D. A. Meyer and N. R. Wallach, J. Math. Phys. 43, 4273 (2002)]. Contrarily to GE the main feature of this measure lies in the fact that we study the mean linear entropy of all possible partitions of a multipartite system. This allows the construction of an operational multipartite entanglement measure which is able to distinguish among different multipartite entangled states that GE failed to discriminate. Furthermore, it is also maximum at the critical point of the Ising chain in a transverse magnetic field, being thus able to detect a quantum phase transition.Comment: 14 pages, RevTex4, published versio

Symmetry breaking effects upon bipartite and multipartite entanglement in the XY model

We analyze the bipartite and multipartite entanglement for the ground state of the one-dimensional XY model in a transverse magnetic field in the thermodynamical limit. We explicitly take into account the spontaneous symmetry breaking in order to explore the relation between entanglement and quantum phase transitions. As a result we show that while both bipartite and multipartite entanglement can be enhanced by spontaneous symmetry breaking deep into the ferromagnetic phase, only the latter is affected by it in the vicinity of the critical point. This result adds to the evidence that multipartite, and not bipartite, entanglement is the fundamental indicator of long range correlations in quantum phase transitions.Comment: 13 pages, 19 figures, comments welcome. V2: small changes, published versio

Thermodynamic and dynamic anomalies for a three dimensional isotropic core-softened potential

Using molecular dynamics simulations and integral equations (Rogers-Young, Percus-Yevick and hypernetted chain closures) we investigate the thermodynamic of particles interacting with continuous core-softened intermolecular potential. Dynamic properties are also analyzed by the simulations. We show that, for a chosen shape of the potential, the density, at constant pressure, has a maximum for a certain temperature. The line of temperatures of maximum density (TMD) was determined in the pressure-temperature phase diagram. Similarly the diffusion constant at a constant temperature, $D$, has a maximum at a density $\rho_{max}$ and a minimum at a density $\rho_{min}<\rho_{max}$. In the pressure-temperature phase-diagram the line of extrema in diffusivity is outside of TMD line. Although in this interparticle potential lacks directionality, this is the same behavior observed in SPC/E water.Comment: 16 page

Angiotensin-(1–7)/Mas axis integrity is required for the expression of object recognition memory

AbstractIt has been shown that the brain has its own intrinsic renin–angiotensin system (RAS) and angiotensin-(1–7) (Ang-(1–7)) is particularly interesting, because it appears to counterbalance most of the Ang II effects. Ang-(1–7) exerts its biological function through activation of the G-protein-coupled receptor Mas. Interestingly, hippocampus is one of the regions with higher expression of Mas. However, the role of Ang-(1–7)/Mas axis in hippocampus-dependent memories is still poorly understood. Here we demonstrated that Mas ablation, as well as the blockade of Mas in the CA1-hippocampus, impaired object recognition memory (ORM). We also demonstrated that the blockade of Ang II receptors AT1, but not AT2, recovers ORM impairment of Mas-deficient mice. Considering that high concentrations of Ang-(1–7) may activate AT1 receptors, nonspecifically, we evaluate the levels of Ang-(1–7) and its main precursors Ang I and Ang II in the hippocampus of Mas-deficient mice. The Ang I and Ang II levels are unaltered in the whole hipocampus of MasKo. However, Ang-(1–7) concentration is increased in the whole hippocampus of MasKo mice, as well as in the CA1 area. Taken together, our findings suggest that the functionality of the Ang-(1–7)/Mas axis is essential for normal ORM processing

Desenvolvimento de software para produção de biodiesel a partir do óleo residual

CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMO: A demanda por energia cresce mais a cada ano e com isso aumenta a poluição. O biodiesel existe como uma alternativa ao diesel derivado do petróleo. Biodiesel é obtido por uma reação de transesterificação entre um óleo vegetal ou gordura animal e um álcool de cadeia curta. O óleo de soja residual é uma alternativa de utilização de um resíduo para produção desse biocombustível. O presente estudo traz o desenvolvimento de um software que vem a ser apoio na produção de biodiesel a partir do óleo residual. Foram feitas reações para produção de biodiesel a partir do óleo de soja residual alterando as variáveis: tipo de catalisador (KOH e NaOH), razão molar óleo:metanol (1:5 e 1:7) e tempo de reação de reação (40 min e 1h). O maior rendimento de óleo em biodiesel de 97,30% foi obtido na reação utilizando a razão molar óleo:metanol de 1:7, KOH como catalisador na temperatura de 50ºC por 1h. O software coleta do usuário a massa do óleo, dispondo com isto o catalisador a ser utilizado, quantidade de massa do catalisador e álcool, tempo reacional, temperatura e porção necessária ou não de HCl para posterior purificação.ABSTRACT: The demand for energy grows more each year and with it increases pollution. Biodiesel exists as an alternative to diesel derived from petroleum. Biodiesel is obtained by a transesterification reaction between a vegetable oil or animal fat and a short-chain alcohol. Residual soybean oil is an alternative to using a residue to produce this biofuel. The present study brings the development of software that comes to support the production of biodiesel from residual oil. Reactions were made for the production of biodiesel from residual soy oil by changing the variables: type of catalyst (KOH and NaOH), molar ratio oil: methanol (1: 5 and 1: 7) and reaction time of reaction (40 min and 1h). The highest oil yield in biodiesel of 97.30% was obtained in the reaction using the oil: methanol molar ratio of 1: 7, KOH as a catalyst at a temperature of 50ºC for 1h. The software collects the mass of the oil from the user, thereby providing the catalyst to be used, the amount of mass of the catalyst and alcohol, reaction time, temperature and the necessary portion or not of HCl for further purification.info:eu-repo/semantics/publishedVersio

The partial inhibition of hypothalamic IRX3 exacerbates obesity

The Iroquois homeobox 3 (Irx3) gene has been identified as a functional long-range target of obesity-associated variants within the fat mass and obesity-associated protein (FTO) gene. It is highly expressed in the hypothalamus, and both whole-body knockout and hypothalamic restricted abrogation of its expression results in a lean phenotype, which is mostly explained by the resulting increased energy expenditure in the brown adipose tissue. Because of its potential implication in the pathogenesis of obesity, we evaluated the hypothalamic cell distribution of Irx3 and the outcomes of inhibiting its expression in a rodent model of diet-induced obesity. Methods: Bioinformatics tools were used to evaluate the correlations between hypothalamic Irx3 and neurotransmitters, markers of thermogenesis and obesity related phenotypes. Droplet-sequencing analysis in >20,000 hypothalamic cells was used to explore the types of hypothalamic cells expressing Irx3. Lentivirus was used to inhibit hypothalamic Irx3 and the resulting phenotype was studied. Findings: IRX3 is expressed predominantly in POMC neurons. Its expression is inhibited during prolonged fasting, as well as when mice are fed a high-fat diet. The partial inhibition of hypothalamic Irx3 using a lentivirus resulted in increased diet-induced body mass gain and adiposity due to increased caloric intake and reduced energy expenditure. Interpretation: Contrary to the results obtained when lean mice are submitted to complete inhibition of Irx3, partial inhibition of hypothalamic Irx3 in obese mice causes an exacerbation of the obese phenotype. These data suggest that at least some of the Irx3 functions in the hypothalamus are regulated according to a hormetic pattern, and modulation of its expression can be a novel approach to modifying the body's energy-handling regulation.39448460FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2013/07607-8; 2017/02983-