An alternative BRST operator for topological Landau-Ginzburg models

We propose a new BRST operator for the B-twist of N = 2 Landau-Ginzburg (LG) models. It solves the problem of the fractional ghost numbers of Vafaʹs old BRST operator and shows how the model is obtained by gauge fixing a zero action. An essential role is played by the anti-BRST operator, which is given by one of the supersymmetries of the N = 2 algebra. Its presence is needed in proving that the model is indeed a topological field theory. The space of physical observables, defined by taking the anti-BRST cohomology in the BRST cohomology groups, is unchanged.