Executive Summary
The ACES/PHARAO mission is poised to provide the most precise measurements of gravitational redshift to date, requiring an unprecedented understanding of all potential systematic errors. We propose a collaborative, post-hoc data analysis project to search the mission's high-precision clock stability data (e.g., Allan deviation, phase noise spectra) for unexplained, low-level correlations. Certain emergent gravity frameworks predict the existence of a dynamic spacetime substrate that could manifest as subtle, anomalous frequency noise. Our analysis would search for correlations between the clock's frequency fluctuations and external factors, such as the satellite's orientation relative to cosmic reference frames (e.g., the CMB dipole) or temporal correlation with high-energy astrophysical events (e.g., GRBs). This project requires no modification to the mission's hardware or operations. The primary goal is to assist in characterizing the instrument's noise floor at a fundamental level, with the potential secondary benefit of discovering new physics or placing world-leading constraints on theories beyond the Standard Model.
1. Scientific Motivation: Characterizing the Ultimate Noise Floor
At the level of precision targeted by ACES/PHARAO, the distinction between instrumental noise and new physical phenomena becomes blurred. A thorough understanding of every source of frequency instability is paramount to achieving your core mission goals. Our theoretical work suggests that what might appear as a subtle, unexplained flicker noise could, in principle, be a signature of the quantum nature of spacetime itself.
This proposal offers a theoretical framework to guide a search for such signatures within your data. By systematically looking for correlations that standard physics does not predict, we can either rule them out and thereby increase confidence in the final GR measurement, or we can identify a potential anomaly that warrants further investigation.
2. The Core Hypothesis & Search Signatures
We hypothesize that the local rate of time flow is not only subject to gravitational redshift but also to minute fluctuations from an underlying dynamic spacetime medium. We propose to search for two primary signatures of this effect in the ACES/PHARAO data:
- Directional Anisotropy: A minute, periodic variation in the clock's frequency that correlates with the satellite's orientation relative to the CMB dipole or the galactic plane. This would test for a subtle, residual "preferred frame" effect that is predicted by some discrete spacetime models.
- Stochastic Correlation with High-Energy Events: A search for statistically significant, transient frequency fluctuations in the clock data that are temporally correlated with independently observed high-energy events, such as Gamma-Ray Bursts (GRBs) or solar flares detected by other observatories. This would test the hypothesis that intense observational events (`O`) can cause a detectable local modulation of the spacetime substrate.
3. Proposed Analysis Protocol
This is a purely computational, collaborative project.
- Data Required: We would request access to the long-term, high-cadence time-series data of the clock's frequency stability and phase noise, along with the satellite's attitude and orbital telemetry.
- Methodology:
- Perform a spectral analysis of the frequency data, conditioned on the satellite's orientation, to search for the predicted directional anisotropies.
- Conduct a cross-correlation analysis between the clock's noise data and catalogues of astrophysical transient events, using a sliding time window to search for delayed correlations.
- Collaboration: This would be a joint effort between our theoretical group and your instrument team to ensure a correct interpretation of the data and a rigorous understanding of all instrumental systematics.
4. Potential Impact & Alignment with Mission Goals
This project is designed to directly support the primary objectives of the ACES/PHARAO mission.
- Enhancing the Primary Result: By searching for and placing stringent limits on these hypothetical anomalous correlations, we can strengthen the final gravitational redshift measurement. A null result provides a powerful statement that no new physics was detected at this level of precision, bolstering the confirmation of General Relativity.
- High-Discovery Potential: In the unlikely but transformative event that a statistically significant correlation is found, it would represent a monumental discovery made possible by the unparalleled sensitivity of your instrument.
We believe this no-cost, purely analytical collaboration offers a valuable opportunity to deepen the scientific return of the ACES/PHARAO mission, contributing to a more complete understanding of both the instrument and the fundamental nature of spacetime.