Abstract
Quantum states can be understood as either (i) describing quantum systems or (ii) representing observes' knowledge about quantum systems. These different meanings are shown to imply different transformation properties in relativistic field theories. The rules for the reduction of quantum states and the transformation properties of quantum states under Lorentz transformations are derived for case (ii). The results obtained are applied to a quantum system recently presented and analyzed by Aharonov and Albert. It is shown that the present results, combined with Aharonov and Albert's, amount to a proof of Bohr's view that quantum states represent observes' knowledge about quantum systems.
- Received 3 February 1982
DOI:https://doi.org/10.1103/PhysRevD.26.1330
©1982 American Physical Society