The Cosmological Constant Problem: Why it's hard to get Dark Energy from Micro-physics-archive

Synopsis

http://arxiv.org/abs/1309.4133

In this paper, the author presents the problem of the `old' cosmological constant problem, though the more recent variants are also briefly discussed. These variants naturally emerge when cosmology is embedded within a framework --- effective field theories --- that efficiently captures what is consistent with what is known about the physics-archive of smaller distances. I will attach a brief introduction to the notions of the Renormalization Group in the simplest possible context, and show the way these represent the conceptual issues, such as the relevance or not of quadratic divergences, about which some confusion has arisen over the years. A set of minimal criteria are formulated against which proposed solutions to the problem can be judged, and a brief overview made of the general limitations of most of the approaches.