Speaker: Cliff Burgess (McMaster University)

Abstract: Precision calculations in cosmology (such as of inflationary predictions for primordial fluctuations) are often plagued by infrared problems and issues of secular time dependence. These usually signal the breakdown of perturbative methods at late times. Similar issues about how to make controlled predictions at late times seem also to arise for information loss in black holes. This talk briefly summarizes how related problems arise in other areas of physics, and how they are dealt with when they do. It is argued that Master-Equation/Lindblad techniques used in areas like optics also apply to cosmology (and possibly black holes) and can tell us how to extract reliably late-time predictions. The utility of these tools is illustrated by using them to predict how quickly primordial quantum fluctuations decohere after their production during inflation and their later emergence as the classical fluctuations observed to seed structure formation in the later Big Bang Epoch.