Abstract
We show that in the regime in which feedback control is most effective—when measurements are relatively efficient, and feedback is relatively strong—then, in the absence of any sharp inhomogeneity in the noise, it is always best to measure in a basis that does not commute with the system density matrix than one that does. That is, it is optimal to make measurements that disturb the state one is attempting to stabilize.
- Received 25 November 2006
DOI:https://doi.org/10.1103/PhysRevLett.99.020501
©2007 American Physical Society