Suspensions Thermal Noise in the LIGO Gravitational Wave Detector

TL;DR

This paper calculates the maximum sensitivity of LIGO by analyzing suspension thermal noise, introducing a comprehensive method to predict noise in all degrees of freedom and applicable to future detector designs.

Contribution

It presents a new method to calculate suspension thermal noise in all degrees of freedom, unifying previous approaches and enabling extensions to more complex suspensions.

Findings

Calculated maximum sensitivity limited by suspension thermal noise.

Unified approach explains previous approximation methods.

Method applicable to future, more complex suspensions.

Abstract

We present a calculation of the maximum sensitivity achievable by the LIGO Gravitational wave detector in construction, due to limiting thermal noise of its suspensions. We present a method to calculate thermal noise that allows the prediction of the suspension thermal noise in all its 6 degrees of freedom, from the energy dissipation due to the elasticity of the suspension wires. We show how this approach encompasses and explains previous ways to approximate the thermal noise limit in gravitational waver detectors. We show how this approach can be extended to more complicated suspensions to be used in future LIGO detectors.