@article{0529d6ff8b844e3483a43165a871a644,

title = "Quantum correlations between light and the kilogram-mass mirrors of LIGO",

abstract = "The measurement of minuscule forces and displacements with ever greater precision is inhibited by the Heisenberg uncertainty principle, which imposes a limit to the precision with which the position of an object can be measured continuously, known as the standard quantum limit1–4. When light is used as the probe, the standard quantum limit arises from the balance between the uncertainties of the photon radiation pressure applied to the object and of the photon number in the photoelectric detection. The only way to surpass the standard quantum limit is by introducing correlations between the position/momentum uncertainty of the object and the photon number/phase uncertainty of the light that it reflects5. Here we confirm experimentally the theoretical prediction5 that this type of quantum correlation is naturally produced in the Laser Interferometer Gravitational-wave Observatory (LIGO). We characterize and compare noise spectra taken without squeezing and with squeezed vacuum states injected at varying quadrature angles. After subtracting classical noise, our measurements show that the quantum mechanical uncertainties in the phases of the 200-kilowatt laser beams and in the positions of the 40-kilogram mirrors of the Advanced LIGO detectors yield a joint quantum uncertainty that is a factor of 1.4 (3 decibels) below the standard quantum limit. We anticipate that the use of quantum correlations will improve not only the observation of gravitational waves, but also more broadly future quantum noise-limited measurements.",

author = "{LIGO Scientific Collaboration} and Haocun Yu and L. McCuller and M. Tse and N. Kijbunchoo and L. Barsotti and N. Mavalvala and J. Betzwieser and Blair, {C. D.} and Dwyer, {S. E.} and A. Effler and M. Evans and A. Fernandez-Galiana and P. Fritschel and Frolov, {V. V.} and F. Matichard and McClelland, {D. E.} and T. McRae and A. Mullavey and D. Sigg and Slagmolen, {B. J.J.} and C. Whittle and A. Buikema and Y. Chen and Corbitt, {T. R.} and R. Schnabel and R. Abbott and C. Adams and Adhikari, {R. X.} and A. Ananyeva and S. Appert and K. Arai and Areeda, {J. S.} and Y. Asali and Aston, {S. M.} and C. Austin and Baer, {A. M.} and M. Ball and Ballmer, {S. W.} and S. Banagiri and D. Barker and J. Bartlett and Berger, {B. K.} and D. Bhattacharjee and G. Billingsley and S. Biscans and Blair, {R. M.} and N. Bode and P. Booker and R. Bork and A. Bramley and Brooks, {A. F.} and Brown, {D. D.} and C. Cahillane and Cannon, {K. C.} and X. Chen and Ciobanu, {A. A.} and F. Clara and Cooper, {S. J.} and Corley, {K. R.} and Countryman, {S. T.} and Covas, {P. B.} and Coyne, {D. C.} and Datrier, {L. E.H.} and D. Davis and {Di Fronzo}, C. and Dooley, {K. L.} and Driggers, {J. C.} and P. Dupej and T. Etzel and Evans, {T. M.} and J. Feicht and P. Fulda and M. Fyffe and Giaime, {J. A.} and Giardina, {K. D.} and P. Godwin and E. Goetz and S. Gras and C. Gray and R. Gray and Green, {A. C.} and Anchal Gupta and Gustafson, {E. K.} and R. Gustafson and J. Hanks and J. Hanson and T. Hardwick and Hasskew, {R. K.} and Heintze, {M. C.} and Helmling-Cornell, {A. F.} and Holland, {N. A.} and Jones, {J. D.} and S. Kandhasamy and S. Karki and M. Kasprzack and K. Kawabe and King, {P. J.} and Kissel, {J. S.} and Rahul Kumar and M. Landry and Lane, {B. B.} and B. Lantz and M. Laxen and Lecoeuche, {Y. K.} and J. Leviton and J. Liu and M. Lormand and Lundgren, {A. P.} and R. Macas and M. MacInnis and Macleod, {D. M.} and Mansell, {G. L.} and S. M{\'a}rka and Z. M{\'a}rka and Martynov, {D. V.} and K. Mason and Massinger, {T. J.} and R. McCarthy and S. McCormick and J. McIver and G. Mendell and K. Merfeld and Merilh, {E. L.} and F. Meylahn and T. Mistry and R. Mittleman and G. Moreno and Mow-Lowry, {C. M.} and S. Mozzon and Nelson, {T. J.N.} and P. Nguyen and Nuttall, {L. K.} and J. Oberling and Oram, {Richard J.} and C. Osthelder and Ottaway, {D. J.} and H. Overmier and Palamos, {J. R.} and W. Parker and E. Payne and A. Pele and Perez, {C. J.} and M. Pirello and H. Radkins and Ramirez, {K. E.} and Richardson, {J. W.} and K. Riles and Robertson, {N. A.} and Rollins, {J. G.} and Romel, {C. L.} and Romie, {J. H.} and Ross, {M. P.} and K. Ryan and T. Sadecki and Sanchez, {E. J.} and Sanchez, {L. E.} and Saravanan, {T. R.} and Savage, {R. L.} and D. Schaetzl and Schofield, {R. M.S.} and E. Schwartz and D. Sellers and T. Shaffer and Smith, {J. R.} and S. Soni and B. Sorazu and Spencer, {A. P.} and Strain, {K. A.} and L. Sun and Szczepa{\'n}czyk, {M. J.} and M. Thomas and P. Thomas and Thorne, {K. A.} and K. Toland and Torrie, {C. I.} and G. Traylor and Urban, {A. L.} and G. Vajente and G. Valdes and Vander-Hyde, {D. C.} and Veitch, {P. J.} and K. Venkateswara and G. Venugopalan and Viets, {A. D.} and T. Vo and C. Vorvick and M. Wade and Ward, {R. L.} and J. Warner and B. Weaver and R. Weiss and B. Willke and Wipf, {C. C.} and L. Xiao and H. Yamamoto and Hang Yu and L. Zhang and Zucker, {M. E.} and J. Zweizig",

year = "2020",

month = jul,

day = "2",

doi = "10.1038/s41586-020-2420-8",

language = "English",

volume = "583",

pages = "43--47",

journal = "Nature",

issn = "0028-0836",

publisher = "Nature Publishing Group - Macmillan Publishers",

number = "7814",

}