  Due to their nonlocality, Majorana bound states have been proposed to induce
current-current correlations (CCCs) that are completely different from those
induced by low-energy fermionic Andreev bound states. Such characteristics can
be used as a signature to detect Majorana bound states. Herein, we studied the
Majorana and fermionic Andreev bound states in a two-dimensional topological
insulator system. We found that nonlocality occurs for both types of bound
states and that their coupling strengths depend on system parameters in the
same pattern. Majorana and fermionic Andreev bound states show the same
differential CCCs characteristics, thereby indicating a universal behavior for
both types of bound states. The maximal cross differential CCCs are robust to
the structural asymmetry of the system.
