Speaker:	Shin Nakamura (Kyoto University)
Title:	Negative Differential Registivity from Holography
Date (JST):	Thu, Sep 02, 2010, 15:30 - 17:00
Place:	Seminar Room A
Abstract:	Negative differential registivity (NDR) is a non-linear non-equilibrium charge transport widely observed in strongly correlated insulators. However, due to the non-linearity and the non-equilibriumity, NDR in strongly correlated insulators has only been studied within phenomenological models so far. In the present talk, it will be shown for the first time that the charge transport in some strongly interacting gauge theory indeed exhibits NDR by using AdS/CFT. (Ref. arXiv:1006.4105 [hep-th] ) Part 1: I will explain what the NDR is. I will present a basic idea of how to compute the non-linear non-equilibrium charge transport in AdS/CFT and how the NDR is computed. Part 2: I will explain the holographic computation of the NDR in detail. I will also discuss the physical interpretation of the results. The system we consider is a system of mesons and the current we compute is that of the quark charge; it is natural to interpret the results within the quark-hadron physics. However, I point out that the system has several features similar to that of the excitonic insulators of realistic materials. I will overview what the excitonic insulators are. Possible suggestions from our results to the condensed matter physics will also be proposed.

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