Measurement theory for closed quantum systems

[摘要] We introduce the concept of a "classical observable" as an operator with vanishingly small quantum fluctuations on a set of density matrices. Their study provides a natural starting point to analyse the quantum measurement problem. In particular, it allows to identify Schrödinger cats and the associated projection operators intrinsically, without the need to invoke an environment. We discuss how our new approach relates to the open system analysis of quantum measurements and to thermalization studies in closed quantum systems.

[发布机构] TQC, Universiteit Antwerpen, Universiteitsplein 1, Antwerpen; B-2610, Belgium^1

[效力级别] 力学 [学科分类] 力学，机械学

[关键词] Closed quantum system;Density matrix;New approaches;Projection Operator;Quantum fluctuation;Quantum measurement;Thermalization