01000nas a2200121   4500008004300000245004900043210004800092520063900140100002000779700002400799700001900823856003600842       2007                        en_Ud  00aComputing Amplitudes in topological M-theory0 aComputing Amplitudes in topological Mtheory3 aWe define a topological quantum membrane theory on a seven dimensional manifold of $G_2$ holonomy. We describe in detail the path integral evaluation for membrane geometries given by circle bundles over Riemann surfaces. We show that when the target space is $CY_3\\\\times S^1$ quantum amplitudes of non-local observables of membranes wrapping the circle reduce to the A-model amplitudes. \\nIn particular for genus zero we show that our model computes the Gopakumar-Vafa invariants. Moreover, for membranes wrapping calibrated homology spheres in the $CY_3$, we find that the amplitudes of our model are related to Joyce invariants.1 aBonelli, Giulio1 aTanzini, Alessandro1 aZabzine, Maxim  uhttp://hdl.handle.net/1963/1901