Violating the Leggett-Garg inequalities with classical light
File(s)
Accepted version
Author(s)
Chevalier, Hadrien
Paige, AJ
Kwon, Hyukjoon
Kim, MS
Type
Journal Article
Abstract
In an endeavor to better define the distinction between classical macroscopic and quantum microscopic regimes, the Leggett-Garg inequalities were established as a test of macroscopic-realistic theories, which are commonly thought to be a suitable class of descriptions for classical dynamics. The relationship between their violation and nonclassicality is however not obvious. We show that classical states of light, which in the quantum optical sense are any convex sums of coherent states, may not satisfy the Leggett-Garg inequalities. After introducing a simple Mach-Zehnder setup and showing how to obtain a violation with a single photon using negative measurements, we focus on classical states of light, in particular those of low average photon number. We demonstrate how one can still perform negative measurements with an appropriate assignment of variables, and show that the inequalities are violable with coherent states. Finally, we abandon the initial phase reference and demonstrate that the violation is still possible, in particular with thermal states of light, and we investigate the effect of intermediate dephasing.
Date Issued
2021-04-09
Date Acceptance
2021-03-03
Citation
Physical Review A: Atomic, Molecular and Optical Physics, 2021, 103 (4), pp.1-9
ISSN
1050-2947
Publisher
American Physical Society
Start Page
1
End Page
9
Journal / Book Title
Physical Review A: Atomic, Molecular and Optical Physics
Volume
103
Issue
4
Copyright Statement
©2021 American Physical Society
Sponsor
The Royal Society
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000646080500007&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Grant Number
WM140063
Subjects
Science & Technology
Physical Sciences
Optics
Physics, Atomic, Molecular & Chemical
Physics
QUANTUM
COHERENT
STATES
Publication Status
Published
Article Number
ARTN 043707
Date Publish Online
2021-04-09