Generalized Metric Formulation of Double Field Theory on Group Manifolds

Abstract: We rewrite the recently derived cubic action of Double Field Theory on group manifolds [arXiv:1410.6374] in terms of a generalized metric and extrapolate it to all orders in the fields. For the resulting action, we derive the field equations and state them in terms of a generalized curvature scalar and a generalized Ricci tensor. Compared to the generalized metric formulation of DFT derived from tori, all these quantities receive additional contributions related to the non-trivial background. It is shown that the action is invariant under its generalized diffeomorphisms and 2D-diffeomorphisms. Imposing additional constraints relating the background and fluctuations around it, the precise relation between the proposed generalized metric formulation of DFT${}\mathrm{WZW}$ and of original DFT from tori is clarified. Furthermore we show how to relate DFT${}\mathrm{WZW}$ of the WZW background with the flux formulation of original DFT.