Projectively flat bundles and semi-stable Higgs bundles

The Corlette-Donaldson-Hitchin-Simpson’s correspondence states that, on a compact K"ahler manifold $(X,\omega )$, there is a one-to-one correspondence between the moduli space of semisimple flat complex vector bundles and the moduli space of poly-stable Higgs bundles with vanishing Chern numbers. In this paper, we extend this correspondence to the projectively flat bundles case. We prove that there is an equivalence of categories between the category of $\omega$-semi-stable (poly-stable) Higgs bundles $(E, \overline{\partial}{E}, \phi )$with$(2rc{2}(E)-(r-1)c_{1}^{2}(E))\cdot [\omega]^{n-2}=0 $ and the category of (semi-simple) projectively flat bundles $(E,D)$ with $\sqrt{-1}{F}_D=\alpha \otimes I{d}_E$ for some real (1,1)-form $\alpha$. Furthermore, we also establish the above correspondence on some compact non-K"ahler manifolds. As its application, we obtain a vanishing theorem of characteristic classes of projectively flat bundles.