Density Matrix Realism

Eddy Keming Chen

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arXiv · 2405.01025

Density Matrix Realism

Eddy Keming Chen

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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.

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Eddy Keming Chen. 2024-05-02. Density Matrix Realism. https://arxiv.org/abs/2405.01025

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