String Theory seminar - Kazem Bitaghsir Fadafan Seminar

Study of some quantum systems in condensed matter theory such as strange metals and cold atomic phase need to consider strongly interacting many-body quantum physics. To study such strongly interacting systems, the usual theoretical methods are not efficient and one should use new methods which are based on the non-perturbative approaches. Using the gauge-string correspondence is a new tool for studying the transport coefficients in a strongly interacting systems. One of the important observables is the electrical conductivity at finite density and disorder. We discuss the proposed bound of the electrical conductivity in strongly coupled disordered quantum field theories using holography. It is interesting that in the incoherent limit, the transport is given by the diffusion of charge and energy. In this limit, a universal bound for the diffusivities have been proposed from holography which is related to quantum chaos and butterfly velocity. We consider coupling of the Maxwell term to the bulk Weyl tensor and compute the butterfly velocity, charge and energy diffusion with broken translational symmetry.