Abstract
Quantum mechanics allows for states in macroscopic superpositions, but they ordinarily undergo rapid decoherence due to interactions with their environment. A system that only interacts gravitationally, such as an arrangement of dark matter (DM), may exhibit slow decoherence. In this Letter, we compute the decoherence rate of a quantum object within general relativity, focusing on superposed metric oscillations; a rare quantum general relativistic result. For axion DM in a superposition of the field’s phase, we find that DM in the Milky Way is robust against decoherence, while a spatial superposition is not. This novel phase behavior may impact direct detection experiments.
- Received 1 April 2021
- Accepted 24 June 2021
- Corrected 20 July 2021
DOI:https://doi.org/10.1103/PhysRevLett.127.031301
© 2021 American Physical Society
Physics Subject Headings (PhySH)
Corrections
20 July 2021
Correction: Reference [19] contained a typographical error in the name of the fifth author and has been fixed.