Testing the equivalence principle across the Universe: a model-independent approach with galaxy multi-tracing

Abstract

We present a test of the equivalence principle on cosmological scales. This cornerstone of general relativity has been tested with high precision for standard matter, but its validity for the unknown dark matter remains a crucial open question. We construct a measurable quantity $E_P$ that acts as a null test, i.e. it deviates from unity whenever the weak equivalence principle is violated. This quantity can be directly measured from the cross-correlation of two different galaxy populations, thanks to the inclusion of large-scale relativistic corrections. A key feature of our approach is that it only involves minimal assumptions, without the need to specify the power spectrum shape, the background evolution, the growth rate of cosmic structure, the galaxy bias function or a model for the potential violation of the equivalence principle. We provide forecasts for the Dark Energy Spectroscopic Instrument and the Square Kilometre Array (SKA). While the relativistic corrections can be detected with high significance by both surveys, $E_P$ can be constrained up to an interesting level only by SKA, with a precision around 7-15$\%$ within the redshift range $z<0.6$.

v3: updated magnification bias modelling - DESI: matched to simulations, SKA: fixed minor typo; no significant impact on the results

References in corpus (14)

• The Pantheon+ Analysis: Cosmological Constraints
• New Perspective on Galaxy Clustering as a Cosmological Probe: General Relativistic Effects
• Cosmological performance of SKA HI galaxy surveys
• Euclid preparation: XIX. Impact of magnification on photometric galaxy clustering
• Measuring the growth rate of structure with Type IA Supernovae from LSST
• Modeling relativistic contributions to the halo power spectrum dipole
• Principal reconstructed modes of dark energy and gravity
• Gravitational Redshift Constraints on the Effective Theory of Interacting Dark Energy
• Rescuing constraints on modified gravity using gravitational redshift in large-scale structure
• A case study for measuring the relativistic dipole of a galaxy cross-correlation with the Dark Energy Spectroscopic Instrument
• Modified Einstein versus Modified Euler for Dark Matter
• The 6x2pt method: supernova velocities meet multiple tracers
• Disentangling modified gravity from a dark force with gravitational redshift
• Detecting Relativistic Doppler by Multi-Tracing a Single Galaxy Population

Cited by in corpus (5)

• Improved null tests of $\Lambda$CDM and FLRW in light of DESI DR2
• Comparing the motion of dark matter and standard model particles on cosmological scales
• Gravitational Redshift from Galaxy Clusters -- a Relativistic Approach
• Diagnostic Consistency Tests of the Concordance Cosmology
• Detecting Local and Integrated Relativistic Effects by Multi-Tracing a Single Galaxy Population in Harmonic Space