Скачать или смотреть APS DGRAV Seminar: March 2026

Speakers: Begüm Kabagoz and Georgia Mansell.

Title: Squeezing in LIGO: How it works, victories & challenges

Abstract:
Gravitational-wave detectors are broadly limited by quantum noise, originating from the quantum nature of light. In Observing Run 4, the LIGO detectors operated with higher than ever sensitivity (~140-180Mpc binary neutron star range). A major contributor to the improved sensitivity is addition of frequency-dependent squeezed light.

In this talk, we will introduce quantum noise in interferometers: shot noise and radiation pressure noise. We will explain the generation and detection of squeezed states of light and the integration of squeezing into gravitational wave detectors.

We will then present how the quantum noise budget is inferred from calibrated detector data and how squeezed light propagation through the full interferometer is modeled in practice. We identify the major optical loss and phase-noise mechanisms that constrain quantum noise reduction and determine achievable sensitivity, and discuss how these constraints inform future upgrades. We conclude with operational lessons from O4 and implications for next-generation detectors.