Scalable spin squeezing in two-dimensional arrays of dipolar large-SS spins

Controlling the quantum many-body state of arrays of qudits, possessing a large local Hilbert space, opens the path to a broad range of possibilities for many-particle entanglement, interesting both for fundamental quantum science, as well as for potential metrological applications. In this work we theoretically show that the spin-spin interactions realized in two-dimensional Mott insulators of large-spin magnetic atoms (such as Cr, Er or Dy) lead to scalable spin squeezing along the non-equilibrium unitary evolution initialized in a coherent spin state. An experimentally relevant perturbation to the collective squeezing dynamics is offered by a quadratic Zeeman shift, which leads instead to squeezing of individual spins. Making use of a truncated cumulant expansion for the quantum fluctuations of the spin array, we show that, for sufficiently small quadratic shifts, the spin squeezing dynamics is akin to that produced by the paradigmatic one-axis-twisting (OAT) model -- as expected from an effective separation between collective spin and spin-wave variables. Spin squeezing with OAT-like scaling is shown to be protected by the robustness of long-range ferromagnetic order to quadratic shifts in the equilibrium phase diagram of the system, that we reconstruct via quantum Monte Carlo and mean-field theory.Comment: 5+7 pages, 3+6 figure

Durum Wheat Grain Quality Traits as Affected by Nitrogen Fertilization Sources under Mediterranean Rainfed Conditions

Nitrogen application, environmental variation and particularly water deficit and terminal heat that prevail during post grain filling period could significantly affect not only grain yield ability but also quality related traits of durum wheat. A field trial was conducted to evaluate the effect of two nitrogen sources applied at different rates ranging from 0 to 93.8 KgN-1 on yield and grain quality of three durum wheat cultivars. Increased N level from both nitrogen sources (ammonium sulfate nitrate: ASN and urea N) appeared to positively improve yield and grain quality. This effect was particularly significant when for N level superior to 40.2KgNha-1. The average yield increase under maximum N level ranged from 3.23 to 3.37tha-1for urea and ASN respectively. The cultivar Om Rabia appeared to better valorize nitrogen supply and was found associated with higher yielding ability of 1.78tha-1, greater test weight 78.90kg/hl, grain protein content 12.43%, and gluten content 15.20%. This cultivar showed reduced yellow berry of 7.43% under N optimum application. Greater improvements were obtained for ASN than urea for all measured traits. The percentage increases were 6.09% for GY, 2.92% for TW, 4.48% for GP, 5.64% for Gl and 6.88% for CP. These results support that nitrogen derived from ASN and when its application rate is superior to 40.2 KgNha-1 would promote grain yield and quality of durum wheat under rainfall conditions

Different roles of heat shock proteins (70 kDa) during abiotic stresses in barley (Hordeum vulgare) genotypes

In this work, the involvement of heat shock proteins (HSP70) in barley (Hordeum vulgare) has been studied in response to drought and salinity. Thus, 3 barley genotypes usually cultivated and/or selected in Italy, 3 Middle East/North Africa landraces and genotypes and 1 improved genotype from ICARDA have been studied to identify those varieties showing the best stress response. Preliminarily, a bioinformatic characterization of the HSP70s protein family in barley has been made by using annotated Arabidopsis protein sequences. This study identified 20 putative HSP70s orthologs in the barley genome. The construction of un-rooted phylogenetic trees showed the partition into four main branches, and multiple subcellular localizations. The enhanced HSP70s presence upon salt and drought stress was investigated by both immunoblotting and expression analyses. It is worth noting the Northern Africa landraces showed peculiar tolerance behavior versus drought and salt stresses. The drought and salinity conditions indicated the involvement of specific HSP70s to counteract abiotic stress. Particularly, the expression of cytosolic MLOC_67581, mitochondrial MLOC_50972, and encoding for HSP70 isoforms showed different expressions and occurrence upon stress. Therefore, genotypes originated in the semi-arid area of the Mediterranean area can represent an important genetic source for the improvement of commonly cultivated high-yielding varieties

Physiological and molecular osmotic stress responses in three durum wheat (Triticum turgidum ssp durum) genotypes

This study aims to investigate the activities and expression of enzymes of primary metabolism and relate these data with the growth performance of three dierent durum wheat genotypes (Maali; YT13; and ON66) under osmotic stress. Growth traits—including plant height, dry weight (DW) and relative water content (RWC)—were measured to classify genotypes depending on their tolerance to stress. Several enzymes were investigated: Ascorbate peroxidase (APX), Glutamine Synthetase (GS), Glutamine dehydrogenase (GDH), Glutamate synthase (GOGAT), Glucose 6-phosphate dehydrogenase (G6PDH), and Phosphoenolpyruvate Carboxylase (PEPC). The expression of the cytosolic and plastidic glutamine synthetase (TaGS1 and TaGS2), high anity nitrate transporters (TaNRT2.3) and Glutamate dehydrogenase (TaGDH) were also detected by qRT-PCR. The results indicated dierent growth performances among genotypes, indicating Maali and YT13 as tolerant genotypes and ON66 as a drought-susceptible variety. Data showed a decrease in PEPC and increase in APX activities under osmotic stress; a slight decrease in GS activity was observed, together with an increase in G6PDH in all genotypes; GS and NRT2 expressions changed in a similar pattern in the dierent genotypes. Interestingly, Maali and YT13 showed higher transcript abundance for GDH under stress compared to ON66, suggesting the implication of GDH in protective phenomena upon osmotic stress

Scalable spin squeezing in two-dimensional arrays of dipolar large-SS spins

International audienceControlling the quantum many-body state of arrays of qudits, possessing a large local Hilbert space, opens the path to a broad range of possibilities for many-particle entanglement, interesting both for fundamental quantum science, as well as for potential metrological applications. In this work we theoretically show that the spin-spin interactions realized in two-dimensional Mott insulators of large-spin magnetic atoms (such as Cr, Er or Dy) lead to scalable spin squeezing along the non-equilibrium unitary evolution initialized in a coherent spin state. An experimentally relevant perturbation to the collective squeezing dynamics is offered by a quadratic Zeeman shift, which leads instead to squeezing of individual spins. Making use of a truncated cumulant expansion for the quantum fluctuations of the spin array, we show that, for sufficiently small quadratic shifts, the spin squeezing dynamics is akin to that produced by the paradigmatic one-axis-twisting (OAT) model -- as expected from an effective separation between collective spin and spin-wave variables. Spin squeezing with OAT-like scaling is shown to be protected by the robustness of long-range ferromagnetic order to quadratic shifts in the equilibrium phase diagram of the system, that we reconstruct via quantum Monte Carlo and mean-field theory

Phenotypic diversity of Tunisian durum wheat landraces

Tunisia is considered as a diversification centre of durum wheat ( Triticum durum Desf.) and barely ( Hordeum vulgare ). It is characterised by large genetic diversity; however, several genotypes are in the process of disappearance. The safeguard and rehabilitatation of this genetic inheritance requires genetic characterisation, evaluation and in-situ and ex-situ conservation. In this context, a local collection of thirty durum wheat accessions was evaluated using agronomical traits. Three other phenological traits: days to maturity, days to heading and filling period were evaluated. The phenotypic diversity was determined by the Shannon-Weaver diversity Index (H') revealing that number of kernel/spike (H'=0.91), yield (H'=0.89), plant height (H'=0.87) and thousand kernel weight (H'=0.86) had the highest diversity index. Flag leaf area (H'=0.32) showed the weakest index. This germplasm presented average diversity (0.77) showing a large genetic variability. Correlations between traits showed a significant positive relation between yield and spikeless tillers/plant (0.90), thousand kernel weight (0.39), plant height (0.35) and flag leaf area (0.36), suggesting the usefulness of these parameter for selecting for improving grain yield. The components analysis explained 59.61% of total variability and led to identification of a group of accessions Jeneh kotifa 1, Jeneh kotifa 2, Jeneh kotifa 3, Sbei glabre, Hamira 1, Hamira 2, Biskri glabre, Mahmoudi, Biskri glabre AP2, Swabaa Elgia, Sbei, and Mahmoudi glabre showing the best agronomical characteristics. These genotypes can, therefore, be used as parents for the improvement of durum wheat.La Tunisie est un centre de diversité génétique du blé dur ( Triticum durum Desf.) et de l'orge ( Hordeum vulgare ). En dépit de la large diversité génétique au niveau du germoplasme local, plusieurs génotypes sont en voie de disparition. La sauvegarde et la réhabilitation de ce patrimoine génétique nécessitent sa caractérisation, son évaluation ainsi que sa conservation in situ et ex situ. Dans ce contexte une collection locale de trente genotypes de blé dur a été évaluée utilisant des paramètres agronomiques. Trois autres paramètres phénologiques à savoir jours de maturation, jours de rétablissement et période de remplissage étaient aussi évaluées. La diversité phénotypique determinée par l'index de diversité de Shannon-Weaver (H') a révélé que le nombre de grains par épi (H'=0.91), rendement (H'=0.89), hauteur des plants (H'=0.87) et le poids de 1000 grains (H'=0.86) avaient un index de diversité le plus élevé. La surface foliare (H'=0.32) a montré un index le plus faible. Ce germplasm presentait un index de diversité moyen de 0.77 montrant ainsi une large variabilité génétique. Les corrélations entre les paramètres a montré une relation positive significative entre le rendement et le nombre de talles d'épillets par plant (0.39), le poids de 1000 grains (0.35) et la surface foliaire (0.36), suggérant ainsi l'utilité de ces paramètres de sélection pour l'amélioration du rendement en grains. L'analyse des composants a expliqué 59.61% de la variabilité totale et a conduit à identifier un groupe de genotypes entre autre kotifa 2, Jeneh kotifa 3, Sbei glabre, Hamira 1, Hamira 2, Biskri glabre, Mahmoudi, Biskri glabre AP2, Swabaa Elgia, Sbei, Mahmoudi glabre montrant les meilleures caractéristiques agronomiques. Ces génotypes peuvent donc être utilisés comme parents pour l'amélioration de blé dur

Measuring bipartite spin correlations of lattice-trapped dipolar atoms

International audienceWe demonstrate a bipartition technique using a super-lattice architecture to access correlations between alternating planes of a mesoscopic array of spin-3 chromium atoms trapped in a 3D optical lattice. Using this method, we observe that out-of-equilibrium dynamics driven by long-range dipolar interactions lead to spin anti-correlations between the two spatially separated subsystems. Our bipartite measurements reveal a subtle interplay between the anisotropy of the 3D dipolar interactions and that of the lattice structure, without requiring single-site addressing. We compare our results to theoretical predictions based on a truncated cumulant expansion and a new cluster semi-classical method that we use to investigate correlations at the microscopic scale. Comparison with a high-temperature analytical model reveals quantum thermalization at a high negative spin temperature

Changes in yield and yield stability of durum wheat genotypes (triticum turgidum ssp. Durum) under different environments and water regimes

Maintaining high grain yield and genotype performance stability under drought stress is a challenging objective for wheat breeders. This study aims to investigate the agronomic performance of six durum wheat genotypes, grown during three cropping seasons (2017, 2018 and 2019) at three locations in Tunisia: Médenine (south, arid climate) and Kairouan (center, semiarid climate) under two irrigation regimes and Kodia (north, sub-humid climate) under rainfed conditions. We analyzed for these genotypes their responsiveness to these environments through yield components at maturity. Results showed that highest grain yield was recorded under rainfed conditions in the sub-humid region with no significant variability between genotypes. The experiments in semiarid and arid areas were carried out as the combinations (site/year) and were denoted as Environments E1 (Kairouan 2017), E2 (Kairouan 2018) and E3 (Medenine 2019). A significant effect of the interaction genotype by environment (G × E) was observed in all environments, this effect was explained by the variability among climatic factors from one environment to another. Results showed that all the genotypes gave their highest yields in E1. The most productive genotype was Khiar followed by ON15 and YT13 as tolerant genotypes. The susceptible ON66 genotype gave the lowest yield in this environment. Using the stress susceptibility percentage index (SSPI(GY)), results showed that ON15 (11%), Maali (23%) and YT13 (27%) seemed to be more tolerant than Khiar (42%), ON58 (48%) and ON66 (63%) in E1. Stability analysis revealed that according to GY stability ranking, Khiar, Maali, YT13 and ON15 are the most stable genotypes. The tolerant genotype YT13 showed the best stable response and the most performing one contrariwise to the susceptible genotype ON66 which showed the worst performance for GY and lowest yield stability. These results lead to conclude that this pair of genotypes (YT13 and ON66) has an interesting contrasting behavior and could be useful for comparative study in understanding drought tolerance mechanisms and for upcoming breeding programs based on adaptability to Tunisian climates