Trade-off between information gain and fidelity under weak measurements

Longfei Fan, Wenchao Ge, Hyunchul Nha, M. Suhail Zubairy

Research output: Contribution to journalArticle

4 Citations (Scopus)


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.

Original languageEnglish
Article number022114
JournalPhysical Review A - Atomic, Molecular, and Optical Physics
Issue number2
Publication statusPublished - 17 Aug 2015


ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this