Classical interventions in quantum systems. I. The measuring process

Abstract

The measuring process is an external intervention in the dynamics of a quantum system. It involves a unitary interaction of that system with a measuring apparatus, a further interaction of both with an unknown environment causing decoherence, and then the deletion of a subsystem. This description of the measuring process is a substantial generalization of current models in quantum measurement theory. In particular, no ancilla is needed. The final result is represented by a completely positive map of the quantum state $\rho$ (possibly with a change of the dimensions of $\rho$). A continuous limit of the above process leads to Lindblad's equation for the quantum dynamical semigroup.

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References in corpus (2)

• Classical interventions in quantum systems. II. Relativistic invariance
• Derivation of the Lindblad Generator Structure by use of the Itô Stochastic Calculus

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