Resonance widening in spherical GW detectors: model descriptions of the dissipation processes

TL;DR

This paper models how internal friction causes resonance line widening in spherical gravitational wave detectors, analyzing different material assumptions to predict quality factor behavior relevant for detector design.

Contribution

It provides a comparative analysis of dissipation models affecting resonance quality factors in spherical GW detectors based on various material assumptions.

Findings

Quality factor depends on mode frequency in different models

Experimental evidence guides model applicability

Resonance line widening impacts detector sensitivity

Abstract

Internal friction effects are responsible for line widening of the resonance frequencies in mechanical oscillators and result in damped oscillations of its eigenmodes with a decay time Q/\omega. We study the solutions to the equations of motion for the case of spherical oscillators, to be used as next generation of acoustic gravitational wave detectors, based on various different assumptions about the material's constituent equations. Quality factor dependence on mode frequency is determined in each case, and a discussion of its applicability to actual gravitational wave detectors is made on the basis of available experimental evidence.