Abstract
The general impossibility of determining the state of a single quantum system is proved for arbitrary measuring schemes, including a succession of measurements. Some recently proposed methods are critically examined. A scheme for tomographic measurements on a single copy of a radiation field is devised, showing that the system state is perturbed however weak the system-apparatus interaction is, due to the need of preparing the apparatus in a highly “squeezed” state.
- Received 6 September 1995
DOI:https://doi.org/10.1103/PhysRevLett.76.2832
©1996 American Physical Society
