2014/11/20 by P. Hájı́ček, Hajicek, Petr · 1 citation
Computer Science · Physics and Astronomy · #FOS: Physical sciences #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum Physics (quant-ph) #Quantum optics and atomic interactions
paper · pdf · doi:10.48550/arxiv.1411.5524
openalex publication_date 2014/11/20 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
A complete apparatus is defined as reacting to every state of the measured system. Standard quantum mechanics of indistinguishable particles is shown to imply that apparatuses must be incomplete or else they would be drowned out by noise. Each quantum observable is then an abstract representation of many measurement apparatuses, each incomplete in a different way. Moreover, a measured system must be prepared in a state that is orthogonal to the states of all particles of the same type in the environment. This is the main purpose of preparations. A system so prepared is said to have a "separation status". A new, more satisfactory definition of separation status than the spatial one proposed in previous papers then results. Conditions are specified under which the particles in the environment may be ignored as is usually done in the theory of measurement.