Homogeneous Transitions during Inflation: a Description in Quantum Cosmology

Understand

The usual description of inflationary fluctuations uses the framework of quantum field theory (QFT) in curved spacetime, in which quantum fluctuations are superimposed on a classical background spacetime.

• Even for large fluctuations, such as those envisioned during a regime of eternal inflation, this framework is frequently used.
• In the present work we go one step beyond this description by quantising both the scalar field and the scale factor of the universe.
• Employing the Lorentzian path integral formulation of semi-classical gravity we restrict to a simplified minisuperspace setting by considering homogeneous transitions.