Gravitational decoherence

{{Short description|Hypothetical mechanisms by which gravitation can cause quantum decoherence}}

Gravitational decoherence is a term for hypothetical mechanisms by which gravitation can act on quantum mechanical systems to produce decoherence. Advocates of gravitational decoherence include Frigyes Károlyházy, Roger Penrose and Lajos Diósi.{{Cite web|last=Wolchover|first=Natalie|date=March 6, 2018|title=Physicists Find a Way to See the 'Grin' of Quantum Gravity|url=https://www.quantamagazine.org/physicists-find-a-way-to-see-the-grin-of-quantum-gravity-20180306/|access-date=2021-02-13|website=Quanta Magazine|language=en}}{{Cite web|last=Musser|first=George|date=2020-09-07|title=One of quantum physics' greatest paradoxes may have lost its leading explanation|url=https://www.science.org/content/article/one-quantum-physics-greatest-paradoxes-may-have-lost-its-leading-explanation|access-date=2021-02-13|website=Science {{!}} AAAS|language=en}}

A number of experiments have been proposed to test the gravitational decoherence hypothesis.{{Cite journal|last1=Pfister|first1=C.|last2=Kaniewski|first2=J.|last3=Tomamichel|first3=M.|last4=Mantri|first4=A.|last5=Schmucker|first5=R.|last6=McMahon|first6=N.|last7=Milburn|first7=G.|last8=Wehner|first8=S.|date=2016-10-03|title=A universal test for gravitational decoherence|journal=Nature Communications|language=en|volume=7|issue=1|pages=13022|doi=10.1038/ncomms13022|pmid=27694976 |pmc=5063961 |issn=2041-1723|doi-access=free}}{{Cite journal|last1=Marshall|first1=William|last2=Simon|first2=Christoph|last3=Penrose|first3=Roger|last4=Bouwmeester|first4=Dik|date=2003-09-23|title=Towards Quantum Superpositions of a Mirror|url=https://link.aps.org/doi/10.1103/PhysRevLett.91.130401|journal=Physical Review Letters|volume=91|issue=13|pages=130401|doi=10.1103/PhysRevLett.91.130401|pmid=14525288 |arxiv=quant-ph/0210001|s2cid=16651036 }}

Dmitriy Podolskiy and Robert Lanza have argued that gravitational decoherence may explain the existence of the arrow of time.{{Cite journal|last1=Podolskiy|first1=Dmitriy|last2=Lanza|first2=Robert|date=October 2016|title=On decoherence in quantum gravity|journal=Annalen der Physik|language=en|volume=528|issue=9–10|pages=663–676|doi=10.1002/andp.201600011|issn=0003-3804|doi-access=free|arxiv=1508.05377}}