Density Matrix Realism
Abstract
Realism about quantum theory naturally leads to realism about the quantum state of the universe. It leaves open whether it is a pure state represented by a wave function, or an impure (mixed) one represented by a density matrix. I characterize and elaborate on Density Matrix Realism, the thesis that the universal quantum state is objective but can be impure. To clarify the thesis, I compare it with Wave Function Realism, explain the conditions under which they are empirically equivalent, consider two generalizations of Density Matrix Realism, and answer some frequently asked questions. I end by highlighting an implication for scientific realism.
Cite
@article{arxiv.2405.01025,
title = {Density Matrix Realism},
author = {Eddy Keming Chen},
journal= {arXiv preprint arXiv:2405.01025},
year = {2024}
}
Comments
23 pages; accepted version for Michael E. Cuffaro and Stephan Hartmann (eds.), Open Systems: Physics, Metaphysics, and Methodology (2025: Oxford University Press)