Title : Optical and Optomechanical Quantum Correlations in operational Gravitational Wave Detectors 

Location : Amphi Budé – Collège de France – 11 Place Marcelin Berthelot – 75005

A coffee will be offered starting at 10:45 am in room 4, the seminar will start at 11am in room 2.

Abstract : From 2010 to 2015, the gravitational-wave (GW) detector GEO600 was using squeezed light in all of its searches for GWs [1]. The successful sensitivity improvement triggered the implementation of “squeeze lasers” also in Advanced LIGO and Advanced Virgo. In 2019 they started their third observational run with an increased event rate of up to 50% due to the exploitation of squeezed states of light [2,3]. More recently, LIGO’s optical quantum noise was shown to be less than that at the Standard Quantum Limit (SQL) [4]. While a squeezed quantum uncertainty refers to quantum correlations in time, I will explain why the observation in [4] certifies correlations between the quantum uncertainties of the optical field and those of the motion of the 40 kg mirrors [5].

[1] LIGO Scientific Collaboration, Nature Physics 7, 962 (2011);
[2] M. Tse et al., Phys. Rev. Lett. 123, 231107 (2019);
[3] F. Acernese et al., Phys. Rev. Lett. 123, 231108 (2019);
[4] H. Yu et al., Nature 583, 43 (2020);
[5] R. Schnabel and M. Korobko, AVS Quantum Sci 4, 014701 (2022).