English

Operational constraints on state-dependent formulations of quantum error-disturbance trade-off relations

Quantum Physics 2014-05-13 v3

Abstract

We argue for an operational requirement that all state-dependent measures of disturbance should satisfy. Motivated by this natural criterion, we prove that in any dd-dimensional Hilbert space and for any pair of non-commuting operators, AA and BB, there exists a set of at least 2d12^{d-1} zero-noise, zero-disturbance (ZNZD) states, for which the first observable can be measured without noise and the second will not be disturbed. Moreover, we show that it is possible to construct such ZNZD states for which the expectation value of the commutator [A,B][A,B] does not vanish. Therefore any state-dependent error-disturbance relation, based on the expectation value of the commutator as a lower bound, must violate the operational requirement. We also discuss Ozawa's state-dependent error-disturbance relation in light of our results and show that the disturbance measure used in this relation exhibits unphysical properties. We conclude that the trade-off is inevitable only between state-independent measures of error and disturbance.

Keywords

Cite

@article{arxiv.1311.5506,
  title  = {Operational constraints on state-dependent formulations of quantum error-disturbance trade-off relations},
  author = {Kamil Korzekwa and David Jennings and Terry Rudolph},
  journal= {arXiv preprint arXiv:1311.5506},
  year   = {2014}
}

Comments

7 pages. Published version. Improved and expanded discussion