It is of general interest how a quantum measurement may disturb a quantum system while it gives information on the state of the system. We study a trade-off relation between the information gain and the output fidelity for a quantum nondemolition measurement scheme for photon numbers. Toward this aim, we obtain general expressions for the information gain and the output fidelity for an arbitrary initial state. We particularly investigate how these two quantities vary with measurement strength for some specific classes of states, through a single measurement or successive measurements.
|Journal||Physical Review A - Atomic, Molecular, and Optical Physics|
|Publication status||Published - 17 Aug 2015|
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics