Physics Group Meeting

Abstract: I'll review a few recent papers that discuss the subject in the title, focusing on results based on AdS/CFT.References:https://arxiv.org/abs/1603.09745http://arxiv.org/pdf/1510.07911.pdfhttps://arxiv.org/abs/1509.06374For background, see:http://arxiv.org/abs/hep-th/0601001
https://arxiv.org/abs/1011.5120