Observations of fluctuations induced by absorption and emission from high redshift neutral hydrogen in its 21 cm transition have the potential to provide a new and extremely powerful probe of cosmology. This project will predict this signal, to understand better the power of this approach, to select the optimal angular scales and frequency ranges, to determine the best statistics to use, and to quantify the effects of foregrounds. Studying the primordial seeds should constrain the physics responsible for the generation of those perturbations, providing a window into the earliest evolution of the Universe (the epoch of inflation). This might also have important implications for fundamental physics. Analytic and numerical models of the epoch of reionization will both explore parameter space and calibrate against detailed physics.
This work is vitally important to experiments to detect and measure redshifted 21 cm emission, motivating optimal design and observing strategies. Broad dissemination of results and the engagement of students from under-represented groups will spread the benefits of this research, training the next generation of scientists in this emerging area of cosmology.
