Title: Quantum Squeezing in Gravitational-Wave Detectors: How Quantum Correlations Can Help in Studying Black Holes

Place: Seminar del DAA. Jeroni Muñoz Research Building, fourth floor, in Burjassot.

Day: friday, september 20 , 2024. Time: 12:00.

Abstract:

Interferometric gravitational-wave (GW) detectors like LIGO and Virgo, which almost ten years ago inaugurated the era of GW astronomy, are currently in their fourth data-taking period. To date, these detectors have identified more than 200 gravitational-wave candidate sources, mostly from black hole binaries, yielding a wealth of scientific results spanning astrophysics, fundamental physics, and cosmology.

The scientific advancements we can achieve in the future depend critically on the sensitivity of these detectors. If you ask the question: "What is the smallest signal that can be detected by a gravitational-wave detector when all other noise sources are eliminated?" the answer lies in the quantum nature of light used in the measurement process, and this noise arises from vacuum fluctuations that enter the interferometer.

As already proposed in the 80’, by creating quantum correlations, we can modify these vacuum fluctuations and reduce their impact on the detector. In practice, by injecting manipulated, or "squeezed," vacuum states, we can extend our observational reach deeper into the universe.

In this presentation, I will discuss how quantum mechanics poses a fundamental limit to detectors like Virgo and LIGO, how we have come to routinely employ vacuum manipulation techniques, how these techniques have dramatically increased the rate of observed GW sources, and the challenges we face in pushing these methods even further for use in future interferometers like the Einstein Telescope and Cosmic Explorer.