Abstract |
It is conventional to associate quantum gravity physics with the Planck
mass energy scale and to argue that, by the principle of separation of
scales, it is not important at energy scales that are much lower. I will
discuss recent work on when this expectation breaks down. For example, in
the presence of a weakly coupled gauge field or when scalar fields undergo
super-Planckian field variations. I will also discuss new ideas on the
possibility that the principle of separation of scales does not apply to
quantum gravity, so that it exhibits UV/IR mixing, with potential
implications for naturalness and the hierarchy problem. |