Gravitational lensing as a key probe to understand the cosmic acceleration

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In the next decade, large galaxy surveys such as Euclid, LSST and DESI will start to collect data, allowing key cosmological parameters to be determined with much higher precision and different cosmological models to be distinguished from each other. These will also shed light on the challenging fundamental question about the nature of the accelerated cosmic expansion - whether it is due to some dark energy component or a modification to gravity. The first two of these surveys will provide excellent data of weak gravitational lensing, which is one of the key probes to test models for the cosmic acceleration. This project will mainly explore the predictions of lensing observables by the different theoretical models, and how and how well they can be used to constrain models. It will rely on large high-resolution numerical simulations for model predictions and to improve the understanding of the physics underlying key observables. A substantial part of it will be devoted to developing novel methods that are best tailored for testing models given the expected data. There is also the opportunity to combine lensing probes with probes of galaxy clustering (from Euclid and DESI) to improve model constraints.