Thanks to the spectacular observational advances since the 1990s, a 'standard model' of the early universe has now emerged. However, since it is based on quantum field theory in curved space-times, it is not applicable in the Planck regime. Using techniques from loop quantum gravity, the theory can be extended over the 12 orders of magnitude in density and curvature from the onset of inflation...
We introduce Dirac fields in hybrid loop quantum cosmology and study their behavior as part of the primordial perturbations, additional to those of the geometry and the inflaton field. With a convenient ansatz for physical quantum states, we show how to deduce a Schrodinger equation that dictates the quantum evolution of these fermionic perturbations. Remarkably, such evolution is unitary, and...
