Resilience of hidden order to symmetry-preserving disorder

We study the robustness of non-local string order in two paradigmatic disordered spin-chain models, a spin-1/2 cluster-Ising and a spin-1 XXZ Heisenberg chain. In the clean case, they both display a transition from antiferromagnetic to string order. Applying a disorder which preserves the Hamiltonian symmetries, we find that the transition persists in both models. In the disordered cluster-Ising model we can study the transition analytically -- by applying the strongest coupling renormalization group -- and numerically -- by exploiting integrability to study the antiferromagnetic and string order parameters. We map the model into a quadratic fermion chain, where the transition appears as a change in the number of zero-energy edge modes. We also explore its zero-temperature-singularity behavior and find a transition from a non-singular to a singular region, at a point that is different from the one separating non-local and local ordering.} The disordered Heisenberg chain can be treated only numerically: by means of MPS-based simulations, we are able to locate the existence of a transition between antiferromagnetic and string-ordered phase, through the study of order parameters. Finally we discuss possible connections of our findings with many body localization.Comment: 17 pages, 16 figures, version published in PR

Erratum: Entanglement transitions in the quantum Ising chain: A comparison between different unravelings of the same Lindbladian [Phys. Rev. B 105, 064305 (2022)]

Correction to https://dx.doi.org/10.1103/PhysRevB.105.064305

Entanglement dynamics with string measurement operators

We explain how to apply a Gaussian-preserving operator to a fermionic Gaussian state. We use this method to study the evolution of the entanglement entropy of an Ising spin chain following a Lindblad dynamics with string measurement operators, focusing on the quantum-jump unraveling of such Lindbladian. We find that the asymptotic entanglement entropy obeys an area law for finite-range string operators and a volume law for ranges of the string which scale with the system size. The same behavior is observed for the measurement-only dynamics, suggesting that measurements can play a leading role in this context.Comment: 27 pages, 4 figure

Fuzzy Logic Method for the Speed Estimation in All-Wheel Drive Electric Racing Vehicles

This paper presents a method for the vehicle speed estimation with a Fuzzy Logic based algorithm. The algorithm acquires the measurements of the yaw rate, steering angle, wheel velocities and exploits a set of five Fuzzy Logics dedicated to different driving conditions. The technique estimates the speed exploiting a weighted average of the contributions provided by the longitudinal acceleration and the credibility assigned by the Fuzzy Logics to the measurements of the wheels' speed. The method is experimentally evaluated on an all-wheel drive electric racing vehicle and is valid for the front and rear wheel drive configurations. The experimental validation is performed by comparing the obtained estimation with the result of computing the speed as the average of the linear velocity of the four wheels. A comparison to the integral of the vehicle acceleration over time is reported

Signatures of many-body localization in the dynamics of two-site entanglement

We are able to detect clear signatures of dephasing—a distinct trait of many-body localization (MBL)—via the dynamics of two-site entanglement, quantified through the concurrence. Using the protocol implemented by M. Schreiber et al. [Science 349, 842 (2015)], we show that in the MBL phase the average two-site entanglement decays in time as a power law, while in the Anderson localized phase it tends to a plateau. The power-law exponent is not universal and displays a clear dependence on the interaction strength. This behavior is also qualitatively different from the ergodic phase, where the two-site entanglement decays exponentially. All the results are obtained by means of time-dependent density matrix renormalization-group simulations and further corroborated by analytical calculations on an effective model. Two-site entanglement has been measured in cold atoms: our analysis paves the way for the first direct experimental test of many-body dephasing in the MBL phase

From localization to anomalous diffusion in the dynamics of coupled kicked rotors

We study the effect of many-body quantum interference on the dynamics of coupled periodically kicked systems whose classical dynamics is chaotic and shows an unbounded energy increase. We specifically focus on an N-coupled kicked rotors model: We find that the interplay of quantumness and interactions dramatically modifies the system dynamics, inducing a transition between energy saturation and unbounded energy increase. We discuss this phenomenon both numerically and analytically through a mapping onto an N-dimensional Anderson model. The thermodynamic limit N\u2192 1e, in particular, always shows unbounded energy growth. This dynamical delocalization is genuinely quantum and very different from the classical one: Using a mean-field approximation, we see that the system self-organizes so that the energy per site increases in time as a power law with exponent smaller than 1. This wealth of phenomena is a genuine effect of quantum interference: The classical system for N 652 always behaves ergodically with an energy per site linearly increasing in time. Our results show that quantum mechanics can deeply alter the regularity or ergodicity properties of a many-body-driven system

Acúmulo de prolina em cana-de-açúcar sob estresse hídrico ou submetida ao ataque de cigarrinha-das-raízes

A cigarrinha-das-raízes Mahanarva fimbriolata (Stål) (Hemiptera: Cercopidae) tornou-se uma praga importante da cultura da cana-de-açúcar na região centro-sul do Brasil. Estratégias de controle têm sido desenvolvidas, mas os danos promovidos por essa praga e sua interação com a cana-de-açúcar ainda são pouco caracterizados. Em altos níveis de infestação da praga, os sintomas nas plantas são muito semelhantes à restrição hídrica severa. Este trabalho foi conduzido com o objetivo de determinar se o estresse promovido pela infestação de ninfas de cigarrinha-das-raízes resulta em acúmulo de prolina livre, além de comparar dois genótipos de cana-de-açúcar quanto à tolerância ao déficit hídrico. Dois experimentos foram conduzidos em delineamento inteiramente casualizado, em esquema fatorial 2 x 2 x 4 com duas cultivares (SP80-1816 e RB72454), dois níveis de estresse (controle e dez ninfas por planta ou 50% de restrição hídrica) e quatro épocas. O déficit hídrico promovido por M. fimbriolata não resultou em acúmulo de prolina, ilustrando a existência de mecanismos distintos para a percepção do estresse hídrico promovido pela praga e pela variação no potencial osmótico nas células das raízes. A cultivar RB72454 acumula maiores teores de prolina livre, e o acúmulo de massa seca e o crescimento dos colmos são menos afetados nessa cultivar sob restrição hídrica. Os teores de solutos compatíveis provavelmente não podem ser utilizados para quantificar o estresse promovido por M. fimbriolata em cana-de-açúcar. A cultivar RB72454 é mais tolerante ao déficit hídrico do que a cultivar SP80-1816.Mahanarva fimbriolata (Stål) (Hemiptera: Cercopidae) has become a key pest in the sugarcane (Saccharum officinarum) fields of center-south Brazil. Although some control technologies have shown to be efficient, the damage promoted by this spittlebug species and its interaction with sugarcane are poorly characterized. At high infestation levels the symptoms are similar to those of severe water restriction. This work was conducted to determine whether the stress promoted by spittlebug infestation can be measured in terms of free proline accumulation. The water restriction tolerance of two sugarcane genotypes was also compared. Two experiments were set up in a greenhouse and arranged in a completely randomized design in a 2 x 2 x 4 factorial, with two cultivars (SP80-1816 and RB72454), two stress levels (control and ten nymphs per plant or 50% water restriction), and four sampling dates. The water deficit caused by spittlebug nymphs sucking xylem sap does not result in proline accumulation, illustrating that there are different mechanisms to sense when the water deficit is caused by insect feeding or water potential variation in root cells. The cultivar RB72454 accumulates more free-proline, and the dry mass accumulation and stalk growth are less affected in this cultivar under water restriction. The levels of compatible solutes probably cannot be used to measure spittlebug infestation stress in sugarcane and RB72454 is more tolerant to water shortage than SP80-1816

Danos promovidos por cigarrinha-das-raízes na qualidade da cana e processo fermentativo

A qualidade da matéria-prima define o potencial de produção da indústria. A colheita de cana sem queima proporcionou um ambiente favorável ao aumento da infestação da Mahanarva fimbriolata (Stål, 1854), que suga a planta e afeta seu desenvolvimento. Avaliaram-se os danos promovidos pela M. fimbriolata na qualidade da cana e no processo fermentativo. Os tratamentos utilizados foram quatro níveis de danos e duas épocas de avaliações para as análises tecnológicas, e quatro níveis de danos, quatro ciclos fermentativos e duas épocas de avaliações para as análises microbiológicas com três repetições. Foram determinados Brix (sólidos solúveis), Pol (sacarose aparente), Pureza, açúcar redutor total (ART), açúcar redutor (AR), Acidez Total, pH, e teor de compostos fenólicos totais no caldo. No processo fermentativo foram realizadas análises de viabilidade celular, brotos de leveduras e concentração de bactérias. Determinaram-se açúcar redutor residual Total (ARRT), teor alcoólico nos vinhos e a eficiência da fermentação. Os tratamentos com 60% dos colmos danificados apresentaram menor média de Brix, Pol, Pureza e ART do caldo. Verificou-se aumento do AR% caldo e dos teores de compostos fenólicos totais. A viabilidade celular e de brotos foram reduzidas com o aumento dos danos provocados pela M. fimbriolata. O processo fermentativo apresentou maiores quantidades de contaminantes. Com os danos a quantidade de ARRT dos vinhos foi maior, houve redução do teor alcoólico, assim como na eficiência da fermentação. Os danos causados pela M. fimbriolata afetaram a qualidade da matéria-prima, comprometendo o processo fermentativo, além de aumentar a produção de compostos fenólicos e contaminantes.The quality of the raw material defines the industrial potential production. The harvest of raw sugarcane promoted a favorable environment for the increase of Mahanarva fimbriolata (Stål, 1854) pest that affects the plant development. This research was undertaken to evaluate the effects of M. fimbriolata on sugarcane quality and fermentation process. For the technological analysis, four damage levels and two evaluation periods were evaluated, while four fermentation cycles and two evaluation periods were tested for microbiological analysis, with three replications. The determined parameters were Brix (soluble solids), Pol (apparent sucrose), Purity, reducing sugars (RS), total reducing sugars (TRS), Total Acidity, pH and Total Phenolic Compounds in juice. In the fermentation process cellular viability analysis, yeast sprout and bacterial concentration were carried out. The wine was submitted to alcohol content, TRRS (total residual reducing sugars) and fermentation efficiency. The treatment with 60% of damage steams exhibited the lowest averages of Brix, Pol, Purity and TRS of the juice. An increase of the RS% of the juice and content of total phenolic compounds was observed. The cellular and sprouts viability were reduced with the increase in the damages caused by M. fimbriolata. The fermentation process exhibited larger quantities of contaminators. With the damages, the wine TRRS quantity was superior and, consequently there was a decrease of the alcoholic content and fermentation efficiency. The damages caused by M. fimbriolata affected the quality of the raw material, compromising the fermentative process, and increase the production of phenolic compounds and contaminators

Infestação de ninfas de cigarrinhas - das - raízes altera a quantidade de compostos fenólicos em cana - de - açucar

Com a intensificação da colheita mecanizada da cana-de-açúcar sem queima da palhada, a cigarrinha-das-raízes Mahanarva fimbriolata (Stal, 1854) tornou-se uma das principais pragas da cultura, favorecida pelas condições de umidade e baixa variação de temperatura do solo. Poucos trabalhos são dedicados ao estudo da resposta da planta ao ataque deste inseto, dificultando o conhecimento de cultivares resistentes. Os compostos fenólicos são muito estudados por sua ação anti-herbivoria. A presente pesquisa foi conduzida com o objetivo de verificar se o ataque de ninfas de M. fimbriolata induz alterações na quantidade de fenóis totais em cana-de-açúcar. O experimento foi instalado em casa de vegetação, com condições de temperatura e umidade controladas, com delineamento inteiramente casualizado em esquema fatorial 3 X 2 X 4 e três repetições. Ninfas de segundo ínstar de M. fimbriolata foram inoculadas no sistema radicular das plantas, nos níveis: controle, 2-4 e 4-8 ninfas por vaso (primeira-segunda infestação, respectivamente). Os vasos foram cobertos com tela de nylon para isolar o efeito dos adultos, que eram mortos nos monitoramentos diários. Folhas e raízes foram coletadas e congeladas em nitrogênio líquido até a realização das análises. Plantas atacadas por ninfas de M. fimbriolata apresentaram maiores teores de fenóis totais em raízes e folhas. A cultivar SP80-1816 apresentou-se mais responsiva ao ataque das ninfas em raízes. A cultivar SP86-42 apresentou maiores teores de fenóis em raízes e folhas de plantas controle, podendo ser um indicativo da não-preferência dos insetos por esta variedade. O teor de compostos fenólicos parece não ser um bom marcador para identificar genótipos de cana-de-açúcar resistentes a ninfas de M. fimbriolata.The increased rate of sugarcane harvest without previous burn has provided a very favorable environment to the froghopper Mahanarva fimbriolata (Stal, 1854), with high moisture and low temperature variation. Few works have studied the response of sugarcane to this pest, so little is known about resistant cultivars. Plant phenolics are widely studied compounds because of their known antiherbivore effect. This research aims to determine if the attack of M. fimbriolata nymphs stimulates the accumulation of total phenolics in sugarcane. The experiment was carried out in greenhouse and arranged in completely randomized design, in a 3 X 2 X 4 factorial with three replications. Second instar nymphs of M. fimbriolata were infested at the following rates: control, 2-4 and 4-8 nymphs per pot (first-second infestations, respectively). Pots were covered with nylon net and monitored daily to isolate the effect of leaf sucking adults. Leaf and root samples were collected and kept frozen in liquid nitrogen until analyses. Infested plants showed higher levels of phenolics in both root and leaf tissues. In roots, the cultivar SP80-1816 accumulated more phenolic compounds in response to the infestation of M. fimbriolata. On the other hand, higher levels were found in leaves and roots of control plants of SP86-42, which might be an indication of a non-preference mechanism. The increase of total phenolics in sugarcane infested with root-sucking froghopper nymphs does not seem to be useful to detect the resistance to this pest

Effects of secukinumab on serum adipocytokines: preliminary data

Psoriatic arthritis (PsA) is a chronic inflammatory disease that affects joints, connective tissues and the axial skeleton. Metabolic syndrome is an independent risk factor for psoriasis (Pso) development and is associated with more severe forms of Pso. Adipocytokines are secreted by white adipose tissue and are thought to link obesity with the development of metabolic and cardiovascular diseases. Secukinumab is a new monoclonal antibody with a different mechanism of action. This antibody selectively binds to and neutralizes interleukin-17 (IL-17) and it has shown efficacy in the treatment of PsA. The aim of this study was to evaluate the possible interferences of secukinumab on different adipocytokines. We enrolled 28 patients with PsA, classified with the CASPAR criteria. Serum samples were stored at baseline and then at the first, the third and the sixth month of therapy. Resistin, chemerin, adiponectin and C-reactive protein (CRP) were dosed. When tested globally, none of the adipokine tested showed any statistically significant variation. However, when the male group was tested, both resistin and chemerin at M6 showed a significant decrease from baseline. CRP did not show any variation at any time point. Our study demonstrated that treatment with secukinumab has little influence on the levels of adipokines tested within the first six months of treatment even though it might exert different influence between males and females from a metabolic perspective. Further studies with greater numbers of patients are needed to determine whether these preliminary results have clinical relevance