Benchmark calculations for 3H, 4He, 16O and 40Ca with ab-initio coupled-cluster theory

We present ab-initio calculations for 3H, 4He, 16O, and 40Ca based on two-nucleon low-momentum interactions Vlowk within coupled-cluster theory. For 3H and 4He, our results are within 70 keV and 10 keV of the corresponding Faddeev and Faddeev-Yakubovsky energies. We study in detail the convergence with respect to the size of the model space and the single-particle basis. For the heavier nuclei, we report practically converged binding energies and compare with other approaches.