Quantum Coulomb drag signatures of Majorana bound states

Majorana bound states (MBSs), with their non-Abelian statistics and topological protection, are key candidates for fault-tolerant quantum computation. However, their unambiguous identification in solid-state systems remains a fundamental challenge. Here, we present a theoretical study demonstrating that drag transport in a capacitively coupled double quantum dot system offers a robust and nonlocal probe of weakly coupled MBSs. Using the master equation approach, we investigate both steady-state and transient dynamics and uncover a distinctive signature of MBSs, i.e., the emergence of pronounced split peaks in the drag transconductance, directly linked to inter-MBS coupling. We further show that the dynamics of quantum coherence exhibit an inverse correlation with the emergence and enhancement of MBS-induced split peaks in the drag transconductance as the inter-MBS coupling increases. A comparative analysis with Andreev bound states (ABSs) reveals key differences, that is, MBS-induced transconductance peaks are symmetric and robust, while ABS features are asymmetric and sensitive to perturbations. These findings establish clear experimental criteria for distinguishing MBSs and provide a practical framework for probing Majorana physics through nonlocal transport.