Selective readout and back-action reduction for wideband acoustic gravitational wave detectors

TL;DR

This paper introduces a selective readout method for broadband resonant mass gravitational wave detectors that enhances sensitivity by filtering vibrational modes and reducing back-action noise, especially at the quantum limit.

Contribution

The paper proposes a novel selective readout scheme for dual resonant mass detectors that improves sensitivity and reduces back-action noise within a broad frequency band.

Findings

Enhanced spectral strain sensitivity to 2x10^{-23}/√Hz between 2-6 kHz.

Effective reduction of back-action noise within the detector's frequency band.

Potential for significant sensitivity improvements at the quantum limit.

Abstract

We present the concept of selective readout for broadband resonant mass gravitational wave detectors. This detection scheme is capable of specifically selecting the signal from the contributions of the vibrational modes sensitive to the gravitational waves, and efficiently rejecting the contribution from non gravitationally sensitive modes. Moreover this readout, applied to a dual detector, is capable to give an effective reduction of the back-action noise within the frequency band of interest. The overall effect is a significant enhancement in the predicted sensitivity, evaluated at the standard quantum limit for a dual torus detector. A molybdenum detector, 1 m in diameter and equipped with a wide area selective readout, would reach spectral strain sensitivities 2x10^{-23}/sqrt{Hz} between 2-6 kHz.