Quantum ring conductance sensitivity to potential perturbation in an external magnetic field

We study the sensitivity of quantum ring (QR) conductance to potential perturbation introduced by an external charged probe in the context of scanning gate microscopy experiments and analyze its correspondence to the local density of states at the Fermi level for up to four subbands participating in the transport. We find that the conductance of the QR can be weakly sensitive or almost insensitive to the perturbation potential due to magnetic deflection of the wave function. The conductance becomes very sensitive to external perturbations at localized resonances for which the local density of states can be extracted by conductance mapping.