The traditional approach to feedback control is to apply forces to a system by modifying the Hamiltonian. Here we show that quantum systems can be controlled without any Hamiltonian feedback, purely by exploiting the random quantum back-action of a continuous weak measurement. We demonstrate that, quite remarkably, the quantum back-action of such an adaptive measurement is just as effective at controlling quantum systems as traditional feedback.
@article{arxiv.0904.3745,
title = {Feedback Control Using Only Quantum Back-Action},
author = {Kurt Jacobs},
journal= {arXiv preprint arXiv:0904.3745},
year = {2015}
}