Determine the realistic frequency dependence of correlated test-mass acceleration noise

Determine the detailed frequency dependence of the correlated acceleration-noise component between adjacent test masses in future space-based interferometers, beyond the phenomenological white-noise and PSD-scaled prescriptions considered in the study.

Background

The paper models correlations between the acceleration noises of adjacent test masses on the same spacecraft because common disturbances, including those associated with the drag-free and attitude control system, may generate such correlations. It adopts two simplified cross-spectral models: a white-noise spectrum and a spectrum proportional to the acceleration-noise power spectral density.

The authors explicitly note that the actual frequency dependence of the correlated component is not established. This uncertainty limits the physical realism and generality of the quantitative bias estimates, motivating future modeling based on more realistic, frequency-dependent cross spectra and unequal noise levels.

References

Since the detailed frequency dependence of the correlated component is still uncertain, we consider two simple phenomenological models with distinct spectral shapes: a white-noise (WN) model and a PSD-scaled (PS) model.

— Impact of Correlated Test-Mass Noise on Stochastic Gravitational-Wave Background Searches with Space-Based Interferometers  (2610.08140 - Wu et al., 6 Oct 2026) in Section 2.1, “Single-Link Data Model and Correlated Acceleration-Noise Prescription”