Quantum observer, information theory and kolmogorov complexity

Abstract

The theory itself does not tell us which properties are sufficient for a system to count as a quantum mechanical observer. Thus, it remains an open problem to find a suitable language for characterizing observation. We propose an information-theoretic definition of observer, leading to a mathematical criterion of objectivity using the formalism of Kolmogorov complexity. We also suggest an experimental test of the hypothesis that any system, even much smaller than a human being, can be a quantum mechanical observer.