The effective action in four-dimensional CDT

Understand

We present recent results concerning the measurement and analysis of the effective action in four-dimensional Causal Dynamical Triangulations.

• The action describes quantum fluctuations of the spatial volume of the CDT universe (or alternatively the scale factor) after integrating out other degrees of freedom.
• We use the covariance of volume fluctuations to measure and parametrize the effective action inside the de Sitter phase, also called the C phase.
• We show that the action is consistent with a simple discretization of the minisuperspace action (with a reversed overall sign).