Abstract
The notion of probabilistic time is used to explain the origin and possible measurement of time in the Unruh-Wald formulation of quantum gravity. It is shown how ideal and real clocks measure probabilistic time and how we can extract from the Universe a real clock. Afterward, it is also shown how probabilistic time can be endowed with the two fundamental properties of time: it is an ordering parameter and it is ‘‘Heraclitian.’’ We discuss the correlation between the different arrows of time with the quantum arrows defined by the real clock.
- Received 1 April 1993
DOI:https://doi.org/10.1103/PhysRevD.48.1722
©1993 American Physical Society
