Abstract

It is a general quantum mechanical rule that the more information is obtained from an operation on a quantum system, the more its state has to be altered in course of such a procedure. In this talk, we analyze how this rule results in a trade-off between the quality of estimating the state of a quantum system and the disturbance of the original state. We show that the trade-off can be described by a tight analytical inequality quantifying these two effects in terms of mean fidelities. We apply this result to discuss the flow of information in teleportation protocols based on nonmaximally entangled states.

© 2001 Optical Society of America