Document Type

Article

Publication Date

7-31-2021

Abstract

For any choice of initial state and weak assumptions about the Hamiltonian, large isolated quantum systems undergoing Schrödinger evolution spend most of their time in macroscopic superposition states. The result follows from von Neumann’s 1929 Quantum Ergodic Theorem. As a specific example, we consider a box containing a solid ball and some gas molecules. Regardless of the initial state, the system will evolve into a quantum superposition of states with the ball in macroscopically different positions. Thus, despite their seeming fragility, macroscopic superposition states are ubiquitous consequences of quantum evolution. We discuss the connection to many worlds quantum mechanics.

Comments

This is a pre-copy-editing, author-produced PDF of an article accepted for publication in Foundations of Physics, volume 51, in 2021 following peer review. The final publication may differ and is available at Springer via https://doi.org/10.1007/s10701-021-00477-2.

A free-to-read copy of the final published article is available here.

Peer Reviewed

1

Copyright

Springer

Available for download on Sunday, July 31, 2022

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