Quantum feedback control based on entanglement swapping

A scheme of quantum feedback control in which entanglement swapping is used to construct quantum feedback controller is proposed. The output state of the system to be controlled is entangled with the quantum state of a particle near the actuator through entanglement swapping, which constructs a quantum feedback channel, and two pairs of entangled states, two entanglement swapping processes and a unitary transformer together constitute a quantum controller. This feedback strategy can perform some tasks, such as remote control of entangled states and distant feedback of quantum states, which are not possible using quantum control with classical feedback.