Constraining the physics of the early Universe with CMB polarisation

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Perhaps the most useful cosmological probe is the Cosmic Microwave Background (CMB). Thetemperature anisotropies have been measured extremely well by the Planck satellite and thishas established the current concordance cosmological model. However, the CMB has notbeen utilised fully yet: measurements of the CMB polarisation offer an opportunity to probethe physical processes that occurred in the very early Universe. The linear polarisation signalis decomposed into E-mode and B-mode contributions, where the detection of a B-modepolarization signal on large angular scales would demonstrate the existence of primordialgravitational waves. This would be indicative of inflation and provide a platform for exploringphysics at the Grand Unified Theory (GUT) energy scale. The detection of the B-mode signalis thus a major goal of future CMB observations, such as the ground-based Simons array andSimons Observatory, and the satellite LiteBIRD.The polarisation signal of interest is faint and as such optimal observation strategy,instrument design, and data-analysis is necessary. Spurious signals in the data that resemblethe B-mode signature can be generated by instrument and sky scanning imperfections, assuch these must be carefully accounted for. This project's aim is the optimisation of theinstrument design, scan strategy, and data analysis techniques for future CMB experimentsusing analytic techniques and computer simulations