What Happens in a Measurement?
Abstract
It is assumed that in a measurement the system under study interacts with a macroscopic measuring apparatus, in such a way that the density matrix of the measured system evolves according to the Lindblad equation. Under an assumption of non-decreasing von Neumann entropy, conditions on the operators appearing in this equation are given that are necessary and sufficient for the late-time limit of the density matrix to take the form appropriate for a measurement. Where these conditions are satisfied, the Lindblad equation can be solved explicitly. The probabilities appearing in the late-time limit of this general solution are found to agree with the Born rule, and are independent of the details of the operators in the Lindblad equation.
Cite
@article{arxiv.1603.06008,
title = {What Happens in a Measurement?},
author = {Steven Weinberg},
journal= {arXiv preprint arXiv:1603.06008},
year = {2016}
}
Comments
12 pages