Cold atomic energy level population measuring device and method based on quantum feedback

The invention discloses a cold atomic energy level population measuring device and method based on quantum feedback, and the method comprises the steps: carrying out the continuous detection of the atomic energy level population, and obtaining the population information in a source direction; setting feedback Hamiltonian based on the source direction population information; adding a corrected Hamiltonian based on the quantum state evolution trajectory; and feeding back non-source direction population information according to the feedback Hamiltonian and the corrected Hamiltonian to obtain ideal non-source direction population information. The system comprises an atomic module, a feedback control module and a detection module, wherein the feedback control module is respectively connected with the atomic module and the detection module. By using the method and the device, three components of quantum state evolution can be accurately measured, and the limitation that the population in three directions cannot be