Holographic quenches and anomalous transport

Abstract

In my master thesis, I investigated the chiral-magnetic effect in the context of holography; I focused in especially on the impact of the chiral anomaly at transport properties and non-equilbrium behaviour in response to an holographic quench. Concretely, I considered an $U(1)_\text{A}\times U(1)_\text{V}$-Einstein-Maxwell bottom-up model consisting of two massless gauge fields, coupled by a Chern-Simons term in the fivedimensional AdS spacetime. The two gauge fields provide a time dependent electric field and a static magnetic field, parallel to it. As response of the system to quench, I investigated the electromagnetic current in direction of the magnetic field which is generated due to the CME. In the first part of the thesis, I characterised the initial response of the system, in a fixed Schwarzschild AdS background, subjected to a 'fast' quench. The corresponding hyperbolic PDE is solved by means of a fully spectral code in spaces as well as in time direction. Note that this was the first application of a fully spectral code within holography. In the case of 'fast' quenches, the system exhibits an universal scaling behaviour, independent of the external parameters as the strength of the anomaly and the magnetic field, respectively. The late time behaviour of the system shows, depending on the quench and external parameters, in some cases long lived oscillations in the current. Furthermore, I computed the quasi-normal modes of the systems, including the backreaction of the matter fields on the background metric. It turns out that the long lived oscillations appear only in presence of the anomaly and can be traced back to the presence of Landau levels in the system. The results of my master thesis were partly published in arXiv:1607.06817; however, the thesis contains a lot of interesting, and so far unpublished, results and can be viewed as extended version of the paper.