Coherent control of cavity quantum electrodynamics for quantum nondemolition measurements and ultrafast cooling

Quantum nondemolition measurements and ultrafast cooling of single spins are critical for scalable quantum computation. For such purposes, quantum evolution in a coupled structure of a nanodot, a microcavity, and a waveguide can be coherently controlled to establish efficient quantum pathways connecting in sequence an electron spin, a charged exciton, a cavity photon, and finally a flying photon in the waveguide. As an example of suppressing unwanted dynamics in complex solid-state systems, pulse shaping is employed to switch the nanodot-cavity coupling on demand and to perform robust quantum operation.