# Environment as a Witness: Selective Proliferation of Information and Emergence of Objectivity

 Titre Environment as a Witness: Selective Proliferation of Information and Emergence of Objectivity Type de publication Journal Article Nouvelles publications 2005 Auteurs Ollivier, H, Poulin, D, Zurek, WH Journal Physical Review A Volume 72 Pagination 042113 Mots clés Decoherence, Foundations, Quantum Theory Résumé We study the role of the information deposited in the environment of an open quantum system in course of the decoherence process. Redundant spreading of information –- the fact that some observables of the system can be independently read-off'' from many distinct fragments of the environment –- is investigated as the key to effective objectivity, the essential ingredient of classical reality''. This focus on the environment as a communication channel through which observers learn about physical systems underscores importance of quantum Darwinism –- selective proliferation of information about the fittest states'' chosen by the dynamics of decoherence at the expense of their superpositions –- as redundancy imposes the existence of preferred observables. We demonstrate that the only observables that can leave multiple imprints in the environment are the familiar pointer observables singled out by environment-induced superselection (einselection) for their predictability. Many independent observers monitoring the environment will therefore agree on properties of the system as they can only learn about preferred observables. In this operational sense, the selective spreading of information leads to appearance of an objective classical reality'' from within quantum substrate. URL http://www.arxiv.org/abs/quant-ph/0408125 Texte complet