Research Initiation Award: Effect of the Universe Topology on Cosmological Perturbations

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Research Initiation Awards provide support for junior and mid-career faculty at Historically Black Colleges and Universities who are building new research programs or redirecting and rebuilding existing research programs. It is expected that the award helps to further the faculty member's research capability and effectiveness, improves research and teaching at the home institution, and involves undergraduate students in research experiences. The award to North Carolina Central University has potential broader impacts in a number of areas. The goal of this project is to develop a formalism for studying the seeds of structure formation in the early universe in geometries that are different from those that are typically assumed in cosmological research. Undergraduate students are involved in this research and the project has collaborations with a number of other institutions. The project seeks to develop an all-scale cosmological perturbation theory for the following geometrical extensions of the conventional LambdaCDM (Lambda cold dark matter) paradigm, which aim at revealing the shape and volume of the universe: models with anisotropic spatial topologies and models with nonzero spatial curvature. This theory will permit consideration of nonlinear contrasts of the matter density. Thus, it will be suitable for high-precision simulations of the cosmic structure growth at arbitrary - sub-horizon and super-horizon - distances, as well as for the estimation of the cosmological backreaction effects. Elaboration of the desired formalism will be based on the weak field limit, and methods of discrete cosmology, particularly the presentation of nonrelativistic matter in the form of separate point-like particles with the corresponding energy-momentum tensor, in combination with the cosmic screening approach will be employed. The all-scale description of the gravitational interaction in the inhomogeneous universe within the selected models will assist in distinguishing among the competing scenarios, the LambdaCDM paradigm and its alternatives, deepening of our understanding of the universe topology, and constructing an advanced model satisfying the data of present and future high-precision observations.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.