Angular momentum projection in the deformed relativistic Hartree-Bogoliubov theory in continuum

The angular momentum projection (AMP) method is implemented in the deformed relativistic HartreeBogoliubov theory in continuum (DRHBc) with the point-coupling density functional. The wave functions of angular momentum projected states are expanded in terms of the Dirac Woods-Saxon (WS) basis, providing a proper description of the asymptotic behavior of the wave functions. The contribution of continuum induced by the pairing is considered by treating the pairing correlation with the Bogoliubov transformation. We present the formulas and numerical checks for the DRHBc+AMP approach in detail and use it to study low-lying excited states of axially deformed nuclei. Our calculations show that neutron-rich magnesium isotopes Mg-36,Mg-38,Mg-40 are all well-deformed nuclei. The low-lying spectra of these three nuclei are obtained. The ground-state rotational bands of Mg-36,Mg-38,Mg-40 are reproduced reasonably well by using this new DRHBc+AMP approach with the density functional PC-F1.