Contact homology of $S^1$-bundles over some symplectically reduced orbifolds

Abstract

In this paper, we compute contact homology of some quasi-regular contact structures, which admit Hamiltonian actions of Reeb type of Lie groups. We will discuss the toric contact case, (where the torus is of Reeb type), and the case of homogeneous contact manifolds. In both of these cases the quotients by the Reeb action are K\"ahler and admit perfect Morse-Bott functions via the moment map. It turns out that the contact homology depends only on the homology of the symplectic base and the bundle data of the contact manifolds as a circle bundle over the base. Moreover we can identify the relevant holomorphic spheres in the bases which lift to gradient trajectories of the action functional on the loop space of the symplectization of M. In order to include all toric contact manifolds we extend a result of Bourgeois to the case of circle bundles over symplectic orbifolds. In particular we are able to distinguish contact structures on many contact manifolds all in the same first Chern class of $2n$-dimensional plane distributions.