Reduction of quantum noise using the quantum locking with an optical spring for gravitational wave detectors

TL;DR

This paper demonstrates that integrating an optical spring into a quantum locking scheme with homodyne detection broadens the frequency range of quantum noise reduction, enhancing DECIGO's sensitivity to primordial gravitational waves.

Contribution

It introduces a simulation of the optical spring effect within a quantum locking scheme, showing improved quantum noise reduction over a wider frequency band.

Findings

Broader frequency band of quantum noise reduction with optical spring

Enhanced sensitivity of DECIGO to primordial gravitational waves

Significant improvement over previous quantum locking methods

Abstract

In our previous research, simulation showed that a quantum locking scheme with homodyne detection in sub-cavities is effective in surpassing the quantum noise limit for Deci-hertz Interferometer Gravitational Wave Observatory (DECIGO) in a limited frequency range. This time we have simulated an optical spring effect in the sub-cavities of the quantum locking scheme. We found that the optimized total quantum noise is reduced in a broader frequency band, compared to the case without the optical spring effect significantly improving the sensitivity of DECIGO to the primordial gravitational waves.