Seminario di gruppo IV INFN

Bad metals are clean systems with poor conductivity that do not admit a description in terms of long-lived degrees of freedom. Hydrodynamics can account for bad metal phenomenology without providing a precise explanation of the dynamical mechanism at work. Holography offers UV completions which allow to relate the hydrodynamic parameters (such as the rate of momentum dissipation) to the UV details of the model, like the sources and the symmetry pattern. Following the RG flow, one can explicitly get the T dependence of the hydro parameters. One can study the higher non-hydro modes too. Complementary, holography is useful also in completing hydrodynamics from "below", helping in the construction of zero temperature effective theories and candidate ground states to connect the hydrodynamic features to the structure of Goldstone low energy modes.