Density Matrix Realism
Abstract
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 one represented by a density matrix. I characterise 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 generalisations of Density Matrix Realism, and answer some frequently asked questions. I end by highlighting an implication for scientific realism.
Fields of Study & Subjects
Quantum Mechanics and Applications
Relativity and Gravitational Theory
Noncommutative and Quantum Gravity Theories
Publication details
- Journal / source
- Open Systems: Physics, Metaphysics, and Methodology
- Publisher
- Oxford University PressOxford
- Pages
- 260–282
- Publication date
- 15 April 2026
- Language
- EN
- Document type
- Book chapter