On signatures of Planck-scale interactions in the cosmic microwave background radiation

摘要

Based on a rather general low-energy effective action (interacting quantum fields in classical curved spacetimes), we calculate potential signatures of new physics (e.g., quantum gravity) at ultra-high energies (such as the Planck scale) in the anisotropies of the cosmic microwave background radiation. Special emphasis is laid on the correct treatment of the initial state, which was not derived rigorously in previous works. These Planck-scale interactions create non-Gaussian contributions, and we focus on the three-point function as the most promising observable, which also allows discrimination between models violating and those obeying Lorentz invariance.