Controlling inelastic cotunneling through an interacting quantum dot by a circularly-polarized field

We study inelastic cotunneling through a strong Coulomb-blockaded quantum dot subject to a static magnetic field and a perpendicular circularly-polarized magnetic field using a quantum Langevin equation approach. Our calculation predicts an interesting controllable cotunneling current characteristic, splitting--zero-anomaly--splitting transition of the differential conductance with increasing the driving frequency, ascribing to the role of {\em photon-assisted spin-flip} cotunneling processes.