Parabolic Higgs bundles on projecitive line, quiver varieties and Deligne-Simpson problem

Abstract: We establish an isomorphism between the moduli space of parabolic Higgs bundles on the projective line and quiver variety of star-shaped quiver. As applications, we can solve the nilpotent case of the Deligne-Simpson problem in a geometrical way; and we can show that there is an algebraically completely integrable system structure on the moduli space as well as quiver variety we concerned.