The existence of quantum correlations affects both microscopic and macroscopic systems. On macroscopic systems, they are difficult to observe and usually irrelevant for the system's evolution due to the frequent energy exchange with the environment. The world-wide network of gravitational-wave (GW) observatories exploits optical as well as mechanical systems that are highly macroscopic and largely decoupled from the environment. The quasi-monochromatic light fields in the kilometer-scale arm resonators have photon excitation numbers larger than 1019, and the mirrors that are quasi-free falling in propagation direction of the light fields have masses of around 40 kg. Recent observations on the GW observatories LIGO and Virgo clearly showed that the quantum uncertainty of one system affected the uncertainty of the other. Here, we review these observations and provide links to research goals targeted with mesoscopic optomechanical systems in other fields of fundamental physical research. These may have Gaussian quantum uncertainties as the ones in GW observatories or even non-Gaussian ones, such as Schrödinger cat states.

1.
A.
Aspect
,
P.
Grangier
, and
G.
Roger
,
Phys. Rev. Lett.
47
,
460
(
1981
).
2.
E.
Schrödinger
,
Die Naturwiss.
23
,
807
(
1935
).
3.
5.
Z. Y.
Ou
,
S. F.
Pereira
,
H. J.
Kimble
, and
K. C.
Peng
,
Phys. Rev. Lett.
68
,
3663
(
1992
).
6.
W. P.
Bowen
,
R.
Schnabel
,
H.-A.
Bachor
, and
P. K.
Lam
,
Phys. Rev. Lett.
88
,
093601
(
2002
).
7.
B. P.
Abbott
 et al,
Phys. Rev. Lett.
116
,
061102
(
2016
).
9.
J.
Hollenhorst
,
Phys. Rev. D
19
,
1669
(
1979
).
10.
R. E.
Slusher
,
L. W.
Hollberg
,
B.
Yurke
,
J. C.
Mertz
, and
J. F.
Valley
,
Phys. Rev. Lett.
55
,
2409
(
1985
).
11.
L.-A.
Wu
,
H. J.
Kimble
,
J. L.
Hall
, and
H.
Wu
,
Phys. Rev. Lett.
57
,
2520
(
1986
).
12.
K.
McKenzie
,
N.
Grosse
,
W. P.
Bowen
,
S. E.
Whitcomb
,
M. B.
Gray
,
D. E.
McCelland
, and
P. K.
Lam
,
Phys. Rev. Lett.
93
,
161105
(
2004
).
13.
H.
Vahlbruch
,
S.
Chelkowski
,
B.
Hage
,
A.
Franzen
,
K.
Danzmann
, and
R.
Schnabel
,
Phys. Rev. Lett.
95
,
211102
(
2005
).
14.
H.
Vahlbruch
,
S.
Chelkowski
,
B.
Hage
,
A.
Franzen
,
K.
Danzmann
, and
R.
Schnabel
,
Phys. Rev. Lett.
97
,
011101
(
2006
).
15.
H.
Vahlbruch
,
S.
Chelkowski
,
K.
Danzmann
, and
R.
Schnabel
,
New J. Phys.
9
,
371
(
2007
).
16.
H.
Vahlbruch
,
M.
Mehmet
,
S.
Chelkowski
,
B.
Hage
,
A.
Franzen
,
N.
Lastzka
,
S.
Goßler
,
K.
Danzmann
, and
R.
Schnabel
,
Phys. Rev. Lett.
100
,
033602
(
2008
).
17.
H.
Vahlbruch
,
A.
Khalaidovski
,
N.
Lastzka
,
C.
Gräf
,
K.
Danzmann
, and
R.
Schnabel
,
Classical Quantum Gravity
27
,
084027
(
2010
).
18.
R.
Schnabel
,
N.
Mavalvala
,
D. E.
McClelland
, and
P. K.
Lam
,
Nat. Commun.
1
,
121
(
2010
).
19.
J.
Abadie
 et al,
Nat. Phys.
7
,
962
(
2011
).
20.
H.
Grote
,
K.
Danzmann
,
K. L.
Dooley
,
R.
Schnabel
,
J.
Slutsky
, and
H.
Vahlbruch
,
Phys. Rev. Lett.
110
,
181101
(
2013
).
21.
J.
Lough
 et al,
Phys. Rev. Lett.
126
,
041102
(
2021
).
22.
M.
Tse
 et al,
Phys. Rev. Lett.
123
,
231107
(
2019
).
23.
F.
Acernese
 et al,
Phys. Rev. Lett.
123
,
231108
(
2019
).
24.
R.
Abbott
 et al,
Phys. Rev. X
11
,
021053
(
2021
).
26.
F.
Acernese
 et al,
Phys. Rev. Lett.
125
,
131101
(
2020
).
27.
W.
Marshall
,
C.
Simon
,
R.
Penrose
, and
D.
Bouwmeester
,
Phys. Rev. Lett.
91
,
130401
(
2003
).
28.
H. J.
Kimble
,
Y.
Levin
,
A. B.
Matsko
,
K. S.
Thorne
, and
S. P.
Vyatchanin
,
Phys. Rev. D
65
,
022002
(
2001
).
29.
R.
Schnabel
,
Ann. Phys.
532
,
1900508
(
2020
).
30.
C.
Whittle
 et al,
Science
372
,
1333
(
2021
).
31.
M.
Rossi
,
D.
Mason
,
J.
Chen
, and
A.
Schliesser
,
Phys. Rev. Lett.
123
,
163601
(
2019
).
32.
N.
Aggarwal
 et al,
Nat. Phys.
16
,
784
(
2020
).
33.
C. B.
Møller
 et al,
Nature
547
,
191
(
2017
).
34.
M. J.
Yap
 et al,
Nat. Photonics
14
,
19
(
2020
).
35.
J.
Cripe
,
T.
Cullen
,
Y.
Chen
,
P.
Heu
,
D.
Follman
,
G. D.
Cole
, and
T.
Corbitt
,
Phys. Rev. X
10
,
031065
(
2020
).
36.
D.
Mason
,
J.
Chen
,
M.
Rossi
,
Y.
Tsaturyan
, and
A.
Schliesser
,
Nat. Phys.
15
,
745
(
2019
).
37.
C. F.
Ockeloen-Korppi
,
E.
Damskägg
,
J. M.
Pirkkalainen
,
M.
Asjad
,
A. A.
Clerk
,
F.
Massel
,
M. J.
Woolley
, and
M. A.
Sillanpää
,
Nature
556
,
478
(
2018
).
38.
J.
Chen
,
M.
Rossi
,
D.
Mason
, and
A.
Schliesser
,
Nat. Commun.
11
,
943
(
2020
).
39.
R. A.
Thomas
 et al,
Nat. Phys.
17
,
228
(
2021
).
40.
41.
R.
Riedinger
,
S.
Hong
,
R. A.
Norte
,
J. A.
Slater
,
J.
Shang
,
A. G.
Krause
,
V.
Anant
,
M.
Aspelmeyer
, and
S.
Gröblacher
,
Nature
530
,
313
(
2016
).
42.
S.
Hong
,
R.
Riedinger
,
I.
Marinković
,
A.
Wallucks
,
S. G.
Hofer
,
R. A.
Norte
,
M.
Aspelmeyer
, and
S.
Gröblacher
,
Science
358
,
203
(
2017
).
43.
I.
Marinković
,
A.
Wallucks
,
R.
Riedinger
,
S.
Hong
,
M.
Aspelmeyer
, and
S.
Gröblacher
,
Phys. Rev. Lett.
121
,
220404
(
2018
).
44.
D.
Carney
 et al,
Quantum Sci. Technol.
6
,
024002
(
2021
).
45.
C.
Gonzalez-Ballestero
,
M.
Aspelmeyer
,
L.
Novotny
,
R.
Quidant
, and
O.
Romero-Isart
,
Science
374
,
eabg3027
(
2021
).
46.
M. T.
Jaekel
and
S.
Reynaud
,
Europhys. Lett.
13
,
301
(
1990
).
47.
C. M.
Caves
and
B. L.
Schumaker
,
Phys. Rev. A
31
,
3068
(
1985
).
48.
49.
K. W.
Murch
,
K. L.
Moore
,
S.
Gupta
, and
D. M.
Stamper-Kurn
,
Nat. Phys.
4
,
561
(
2008
).
50.
T. P.
Purdy
,
R. W.
Peterson
, and
C. A.
Regal
,
Science
339
,
801
(
2013
).
51.
S. L.
Danilishin
and
F. Y.
Khalili
,
Living Rev. Relativ.
15
,
5
(
2012
).
52.
V. B.
Braginsky
and
A. B.
Manukin
,
Sov. Phys. JETP
25
,
653
(
1967
).
53.
V. B.
Braginsky
and
F. Y.
Khalili
,
Quantum Measurement
, edited by
K. S.
Thorne
(
Cambridge University
,
Cambridge
,
1995
).
54.
A. V.
Cumming
 et al,
Classical Quantum Gravity
29
,
035003
(
2012
).
55.
M.
Granata
 et al,
Appl. Opt.
59
,
A229
(
2020
).
56.
J. V.
Van Heijningen
,
A.
Bertolini
,
E.
Hennes
,
M. G.
Beker
,
M.
Doets
,
H. J.
Bulten
,
K.
Agatsuma
,
T.
Sekiguchi
, and
J. F.
Van Den Brand
,
Classical Quantum Gravity
36
,
075007
(
2019
).
57.
S. L.
Danilishin
,
F. Y.
Khalili
, and
H.
Miao
, arXiv:1903.05223 (
2019
).
58.
W. H.
Zurek
,
Rev. Mod. Phys.
75
,
715
(
2003
).
59.
G. C.
Ghirardi
,
P.
Pearle
, and
A.
Rimini
,
Phys. Rev. A
42
,
78
(
1990
).
60.
A.
Bassi
and
G.
Ghirardi
,
Phys. Rep.
379
,
257
(
2003
).
61.
A.
Bassi
,
K.
Lochan
,
S.
Satin
,
T.
Singh
, and
H.
Ulbricht
,
Rev. Mod. Phys.
85
,
471
(
2013
).
63.
64.
R.
Penrose
,
Gen. Relativ. Gravitation
28
,
581
(
1996
).
65.
R.
Penrose
,
Philos. Trans. R. Soc. London, Ser. A
356
,
1927
(
1998
).
66.
F.
Karolyhazy
,
Il Nuovo Cimento A
42
,
390
(
1966
).
67.
A.
Bassi
,
A.
Großardt
, and
H.
Ulbricht
,
Classical Quantum Gravity
34
,
193002
(
2017
).
68.
S.
Bose
,
K.
Jacobs
, and
P.
Knight
,
Phys. Rev. A
59
,
3204
(
1999
).
69.
J. Z.
Bernád
,
L.
Diósi
, and
T.
Geszti
,
Phys. Rev. Lett.
97
,
250404
(
2006
).
71.
D.
Kleckner
,
I.
Pikovski
,
E.
Jeffrey
,
L.
Ament
,
E.
Eliel
,
J.
Van Den Brink
, and
D.
Bouwmeester
,
New J. Phys.
10
,
095020
(
2008
).
72.
S.
Bose
 et al,
Phys. Rev. Lett.
119
,
240401
(
2017
).
73.
S.
Nimmrichter
,
K.
Hornberger
,
P.
Haslinger
, and
M.
Arndt
,
Phys. Rev. A
83
,
043621
(
2011
).
74.
R.
Howl
,
R.
Penrose
, and
I.
Fuentes
,
New J. Phys.
21
,
043047
(
2019
).
75.
A. I.
Lvovsky
,
H.
Hansen
,
T.
Aichele
,
O.
Benson
, and
J.
Mlynek
,
Phys. Rev. Lett.
87
,
50402
(
2001
).
76.
R.
Riedinger
,
A.
Wallucks
,
I.
Marinković
,
C.
Löschnauer
,
M.
Aspelmeyer
,
S.
Hong
, and
S.
Gröblacher
,
Nature
556
,
473
(
2018
).
77.
F.
Khalili
,
S.
Danilishin
,
H.
Miao
,
H.
Müller-Ebhardt
,
H.
Yang
, and
Y.
Chen
,
Phys. Rev. Lett.
105
,
070403
(
2010
).
78.
J.
Zhang
,
K.
Peng
, and
S.
Braunstein
,
Phys. Rev. A
68
,
013808
(
2003
).
79.
S.
Nimmrichter
,
K.
Hornberger
, and
K.
Hammerer
,
Phys. Rev. Lett.
113
,
020405
(
2014
).
80.
H.
Vahlbruch
,
M.
Mehmet
,
K.
Danzmann
, and
R.
Schnabel
,
Phys. Rev. Lett.
117
,
110801
(
2016
).
81.
S.
Bose
,
K.
Jacobs
, and
P.
Knight
,
Phys. Rev. A
56
,
4175
(
1997
).
82.
D.
Vitali
,
S.
Mancini
, and
P.
Tombesi
,
J. Phys. A
40
,
8055
(
2007
).
83.
H.
Müller-Ebhardt
,
H.
Rehbein
,
R.
Schnabel
,
K.
Danzmann
, and
Y.
Chen
,
Phys. Rev. Lett.
100
,
013601
(
2008
).
84.
H.
Müller-Ebhardt
,
H.
Rehbein
,
C.
Li
,
Y.
Mino
,
K.
Somiya
,
R.
Schnabel
,
K.
Danzmann
, and
Y.
Chen
,
Phys. Rev. A
80
,
043802
(
2009
).
85.
R.
Schnabel
,
Phys. Rev. A
92
,
012126
(
2015
).
86.
H.
Müller-Ebhardt
, “
On quantum effects in the dynamics of macroscopic test masses
,” Ph.D. thesis (
Leibniz Universität Hannover
,
2009
).
87.
U. B.
Hoff
,
J.
Kollath-Bönig
,
J. S.
Neergaard-Nielsen
, and
U. L.
Andersen
,
Phys. Rev. Lett.
117
,
143601
(
2016
).
88.
S. G.
Hofer
and
K.
Hammerer
,
Phys. Rev. A
91
,
033822
(
2015
).
89.
W.
Wieczorek
,
S. G.
Hofer
,
J.
Hoelscher-Obermaier
,
R.
Riedinger
,
K.
Hammerer
, and
M.
Aspelmeyer
,
Phys. Rev. Lett.
114
,
223601
(
2015
).
90.
K. W.
Murch
,
S. J.
Weber
,
C.
Macklin
, and
I.
Siddiqi
,
Nature
502
,
211
(
2013
).
91.
C.
Gut
 et al,
Phys. Rev. Res.
2
,
033244
(
2020
).
92.
L.
Magrini
,
P.
Rosenzweig
,
C.
Bach
,
A.
Deutschmann-Olek
,
S. G.
Hofer
,
S.
Hong
,
N.
Kiesel
,
A.
Kugi
, and
M.
Aspelmeyer
,
Nature
595
,
373
(
2021
).
93.
B.
Helou
,
J.
Luo
,
H.-C.
Yeh
,
C.-G.
Shao
,
B. J. J.
Slagmolen
,
D. E.
McClelland
, and
Y.
Chen
,
Phys. Rev. D
96
,
044008
(
2017
).
94.
H.
Miao
,
S.
Danilishin
,
H.
Müller-Ebhardt
,
H.
Rehbein
,
K.
Somiya
, and
Y.
Chen
,
Phys. Rev. A
81
,
012114
(
2010
).
95.
S.
Danilishin
,
H.
Miao
,
H.
Müller-Ebhardt
, and
Y.
Chen
,
Proceedings of the First International Workshop on ECS and its Application to QIS
(
2013
).
96.
97.
S.
Rowan
,
J.
Hough
, and
D.
Crooks
,
Phys. Lett. A
347
,
25
(
2005
).
98.
D. J.
Ottaway
,
P.
Fritschel
, and
S. J.
Waldman
,
Opt. Express
20
,
8329
(
2012
).
99.
P.
Kwee
 et al,
Opt. Express
20
,
10617
(
2012
).
100.
S.
Steinlechner
,
J.
Bauchrowitz
,
M.
Meinders
,
H.
Müller-Ebhardt
,
K.
Danzmann
, and
R.
Schnabel
,
Nat. Photonics
7
,
626
(
2013
).
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