Talks

I will discuss a holographic model whose low-energy physics may be used to build a marginal Fermi liquid. The model has several interesting features, including (i.) it is embedded in string theory and we possess a Lagrangian description of the field theory, (ii.) it exhibits a first-order transition between the non-Fermi liquid phase and a normal Fermi liquid phase, and (iii.) the model involves a lattice of heavy defects interacting with a sea of propagating fields.

Various self-similar spherically symmetric spacetimes admit naked singularities, providing a challenge to the cosmic censorship hypothesis. However, it is not clear if the naked singularities are artefacts of the high degree of symmetry of the spacetimes, or if they are potentially generically present. To address this question, we consider perturbations of (various cases of) these spacetimes, focusing particularly on the behaviour of the perturbations as they impinge on the Cauchy horizon. We describe recent results on self-similar Lemaitre-Tolman-Bondi spacetime, indicating stability of scalar and odd parity perturbations, and instability of even parity perturbations.