In this chapter, we introduce our recent results on feedback control of quantum spin systems. The quantum systems are composed of atoms held in a cavity under continuous measurement by photons and a magnetic field that is applied to atoms for controlling the quantum states. The quantum states can be estimated by quan- tum filtering through the continuous measurement, and the intension of magnetic field is controlled depending on the estimations. We show that our proposing control input attains the global stability on the assigned eigenstates.

Inspec keywords: stability; magnetic fields; photons; eigenvalues and eigenfunctions; atoms; feedback; discrete systems

Other keywords: eigenstates; continuous measurement; quantum states; magnetic field; quantum spin systems; atoms; quantum filtering; global stability; photons; continuous feedback control

Subjects: Stability in control theory