Determining the Ground State for Superheavy Nuclei from the Deformed Relativistic Hartree–Bogoliubov Theory in Continuum

The deformed relativistic Hartree–Bogoliubov theory in continuum (DRHBc) has garnered significant attention for its ability to describe the properties of nuclei across the entire nuclear chart, from light to heavy nuclei, including both stable and exotic ones. As part of ongoing efforts to construct a mass table using the DRHBc theory, determining the ground states of nuclei is a crucial task in the systematic studies of deformed nuclei. In this work, a strategy for identifying the ground state in the superheavy nuclei region is proposed and evaluated, by taking Z=134 and 135 isotopes as examples. First, we examine how the step size of the initial quadrupole deformation parameter, Δβ2, affects the pattern of the potential energy curves (PECs) and the determination of the ground state. Our findings indicate that Δβ2=0.05 producing smooth and well-defined PECs while maintaining an acceptable numerical cost. Next, we explore the convergence of PECs with respect to the angular momentum cutoff, Jmax. Based on the results, we recommend using Jmax=31/2ℏ, especially for nuclei with competing oblate and prolate minima. Finally, we conclude that the accurate identification of the ground state can be achieved by performing unconstrained calculations around the minima of the PECs.