Galaxy-CMB Cross-Correlation as a Probe of Alternative Models of Gravity

TL;DR

This paper proposes using galaxy-CMB cross-correlation measurements at redshift 2 to distinguish between TeVeS, an alternative gravity model, and standard general relativity, based on their differing potential well- overdensity relationships.

Contribution

It demonstrates that galaxy-CMB cross-correlation at high redshift can effectively differentiate TeVeS from general relativity, providing a new observational test for gravity models.

Findings

The sign of the galaxy-CMB correlation differs in TeVeS compared to GR at redshift ~2.

This difference is detectable with current or near-future observations.

The method offers a powerful way to test alternative theories of gravity.

Abstract

Bekenstein's alternative to general relativity, TeVeS, reduces to Modified Newtonian Dynamics (MOND) in the galactic limit. On cosmological scales, the (potential well <-> overdensity) relationship is quite different than in standard general relativity. Here we investigate the possibility of cross-correlating galaxies with the cosmic microwave background (CMB) to probe this relationship. At redshifts of order 2, the sign of the CMB-galaxy correlation differs in TeVeS from that in general relativity. We show that this effect is detectable and hence can serve as a powerful discriminator of these two models of gravity.