Lecture “Introduction to quantum squeezing for gravitational wave detectors” by Matteo Barsuglia, CNRS research director at Laboratoire Astroparticule & Cosmologie, Université Paris Cité, will be given on April, the 24th from 9h00 to 12h00 in Salle Pierre Cotton, Institut Fresnel.
The lecture will be given in English
Abstract : The detection of gravitational waves by interferometric detectors such as LIGO and Virgo has inaugurated a new era in astronomy. However, the sensitivity of these instruments is ultimately limited by quantum noise, arising from vacuum fluctuations and the quantum nature of light.
This course provides an introduction to quantum squeezing, a quantum-optical technique that mitigates quantum noise by redistributing the uncertainty of vacuum states. We begin with the theoretical foundations, examining the quantum-mechanical origins of interferometric noise. The concept of squeezed states is then introduced as a means to reduce phase uncertainty at the expense of increased amplitude uncertainty, thereby enhancing the signal-to-noise ratio in gravitational-wave detection. Historical context is provided through Carlton Caves’ seminal 1981 proposal to inject squeezed vacuum in gravitational-wave interferometric detectors. The course then transitions to experimental implementations, highlighting the role of optical parametric oscillators (OPOs) in generating squeezed states, as well as the technical challenges associated with optical losses and the implementation of frequency-dependent squeezing (FDS), which enables quantum noise reduction across the full observational bandwidth of gravitational-wave detectors. Finally, we explore future directions, including the integration of squeezing techniques in next-generation detectors such as the Einstein Telescope.
Biography : Matteo Barsuglia is CNRS research director at Laboratoire Astroparticule & Cosmologie, Université Paris Cité. He has been working for 25 years on the development of the Virgo interferometer for gravitational waves detection. He has been developing techniques to improve the sensitivity of GW detectors through the use of non-gaussian laser modes, reduction of gravity gradient noises and more recently with research about quantum squeezing. Matteo Barsuglia is also the former PI of the French Virgo Collaboration. He is currently member of the board of the Einstein Telescope. Since 2018, he has served as director of the Cosmos, Science, and Society Center a structure focused on education, outreach and the impact of science on the arts and society.
Invitation : Myriam Zerrad, CONCEPT Team – myriam.zerrad@fresnel.fr
