Abstract
A practical way to deal with the problem of time in quantum cosmology and
quantum gravity is proposed. The main tool is effective equations, which
mainly restrict explicit considerations to semiclassical regimes but have the
crucial advantage of allowing the consistent use of local internal times in nondeparameterizable
systems. Different local internal times are related merely by
gauge transformations, thereby enabling relational evolution through turning
points of non-global internal times. The main consequence of the local nature
of internal time is the necessity of its complex valuedness, reminiscent of
more general than non-unitarity of evolution defined for finite ranges of time.
By several general arguments, the consistency of this setting is demonstrated.
Finally, we attempt an outlook on the nature of time in highly quantum regimes.
The focus of this paper is on conceptual issues.
Original language | English |
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Pages (from-to) | 035006/1-035006/18 |
Number of pages | 18 |
Journal | Classical and Quantum Gravity |
Volume | 28 |
DOIs | |
Publication status | Published - 2010 |