Accurate methods for the analysis of strong-drive effects in parametric gates

The ability to perform fast, high-fidelity entangling gates is an important requirement for a viable quantum processor. In practice, achieving fast gates often comes with the penalty of strong-drive effects that are not captured by the rotating-wave approximation. These effects can be analyzed in simulations of the gate protocol, but those are computationally costly and often hide the physics at play. Here, we show how to efficiently extract gate parameters by directly solving a Floquet eigenproblem using exact numerics and a perturbative analytical approach. As an example application of this toolkit, we study the space of parametric gates generated between two fixed-frequency transmon qubits connected by a parametrically driven coupler. Our analytical treatment, based on time-dependent Schrieffer-Wolff perturbation theory, yields closed-form expressions for gate frequencies and spurious interactions, and is valid for strong drives. From these calculations, we identify optimal regimes of operation for different types of gates including $i$SWAP, controlled-Z, and CNOT. These analytical results are supplemented by numerical Floquet computations from which we directly extract drive-dependent gate parameters. This approach has a considerable computational advantage over full simulations of time evolutions. More generally, our combined analytical and numerical strategy allows us to characterize two-qubit gates involving parametrically driven interactions, and can be applied to gate optimization and cross-talk mitigation such as the cancellation of unwanted ZZ interactions in multi-qubit architectures.Comment: 20 pages, 9 figures, 62 reference

Identification of two novel powdery mildew resistance loci, Ren6 and Ren7, from the wild Chinese grape species Vitis piasezkii

Descriptive statistics of the phenotypic scores within the base mapping population 11-373. Powdery mildew symptoms in the field were evaluated in two subsequent years. Greenhouse, in vitro experiments and the qPCR-based molecular assay were carried out with three to four biological replicates of each seedling plant in 2014. (DOCX 14ย�kb

Climate vs grapevine pests and diseases worldwide: the first results of a global survey

Aim: This paper aimed to address the relationship between grapevine disease, pest occurrences and climate. The extremely large extension of viticulture worldwide offers the possibility to evaluate the impacts of climate variability on many aspects of the grape growing system. For this, we initiated a global survey to retrieve the most important diseases and pests in many grape growing regions worldwide and to identify the risk of exposure to pests and diseases of viticulture as a function of climate. Methods and results: Based on the answer of respondent about the main reported diseases/pests in their region, a severity index was calculated. Each region was geolocalised and data were compared to the WorldClim gridded climate database to document the range of climate conditions (growing season temperature and rainfall) associated to the main diseases/pests. The potential climatic-induced changes of grapevine disease and pest geography by 2050 are assessed using agro-climate projections from the ARPEGE CNRM model, using the RCP 4.5 scenario. The preliminary results allow to determine the distribution of diseases as function of agroclimatic indicators. Conclusion: While the distribution of diseases differs according to the region of the world, the current analysis suggests that mildews remain the major phytosanitary threat in most of the regions. Powdery mildew, trunk diseases and viruses were reported in extremely diverse climatic conditions, including intermediate and wet regions.  Significance and impact of the study: This paper present an original methodology to address the relationship between grapevine disease and pest occurrences and climate. Such documentation is scarce in the current literature. Further analysis is currently being performed, including additional survey answers, climate indices and supplementary data collected (spatial extension, frequency of treatments…) to better depict the challenges of grapevine phytosanitary management in a changing climate

Integrated Protection and Production in Viticulture

These last years were marked by increased problems of flavescence dorée in vineyards leading to an increased activity of our research group on it, and the emergence of new models, as well as the arrival of Lobesia botrana in the United States and of Drosophila suzukii in Europe. I hope we will contain any invasion of pierce disease in Europe in the vineyards. I wish we would see one day efficient biological agents against pathogens, and soon the development of molecular tools for early diagnostics in the vineyards and in reservoir host. It is noteworthy that new organisation of the meetings with a plenary session dedicated to IPM allowed to exchange more between entomologist and pathologist and I hope it was in favour to the transfer of the knowledge and methods into practice. We had the pleasure during these last meetings to see more countries participating, especially people outside from the WPRS area, which highlights how the European viticulture and vine protection is attractive and our group is active. I sincerely thank my colleagues who helped me during these years for managing the different sub-groups: Cesare Gessler, Hans Kassemeyer, Andrea Lucchi, Michael Meixner, Denis Thiery, Tirtza Zahavi, Carlo Duso, and Christoph Hoffmann. I greatly appreciate their help and experience in animating the meetings, in sharing their knowledge, in reviewing the papers, but also their friendship which makes our IOBC meetings so friendly. I also would like to thank our two liaison officers Sylvia Blümel and Mauro Jermini who were or are the warrantors of the IOBC institution. But of course, the group is there because people dedicate a lot of their time to organise the meetings. Then I would like to give a particular thank to Hans, Denis, Cesare, Gudrun and all their staff, for organising the meetings, taking the financial risk, to make them so that we only keep in memory the beautiful adventures of sharing knowledge and good wines and of encounters with local people involved into viticulture and passionate by it. This bulletin is the shortest we had since these last seven years (Figure 1) and it highlights that because the stakes of science are increasingly competitive it became more complicated to publish in grey literature. Maybe more systematic publications or special issues in the Biocontrol journal or others could help to perpetuate the production of our IOBC-WPRS group. The reduction of pesticides and Biological control, which is the heart of IOBC-WPRS, is becoming more and more evident in the European legislation, especially for viticulture. But it will probably be necessary for our group to open up to new themes such as plant-pathogen interactions, varietal resistance, biodiversity, ecology, precision viticulture, diagnostic tools and participatory science. Our winegrowers are always more innovative to make new wines, let us be the same for an agroecological viticulture

Singular Perturbation Analysis of Travelling Waves for a Model in Phytopathology

We investigate the structure of travelling waves for a model of a fungal disease propagating over a vineyard. This model is based on a set of ODEs of the SIR-type coupled with two reaction-diffusion equations describing the dispersal of the spores produced by the fungus inside and over the vineyard. An estimate of the biological parameters in the model suggests to use a singular perturbation analysis. It allows us to compute the speed and the profile of the travelling waves. The analytical results are compared with numerical simulations

Signatures of folded branches in the scanning gate microscopy of ballistic electronic cavities

18 pages, 13 figuresInternational audienceWe demonstrate the emergence of classical features in electronic quantum transport for the scanning gate microscopy response in a cavity defined by a quantum point contact and a micron-sized circular reflector. The branches in electronic flow characteristic of a quantum point contact opening on a two-dimensional electron gas with weak disorder are folded by the reflector, yielding a complex spatial pattern. Considering the deflection of classical trajectories by the scanning gate tip allows to establish simple relationships of the scanning pattern, which are in agreement with recent experimental findings