Measuring the Homogeneity of the Universe Using Polarization Drift

Abstract

We propose a method to probe the homogeneity of a general universe, without assuming symmetry. We show that isotropy can be tested at remote locations on the past lightcone by comparing the line-of-sight and transverse expansion rates, using the time dependence of the polarization of Cosmic Microwave Background photons that have been inverse-Compton scattered by the hot gas in massive clusters of galaxies. This probes a combination of remote transverse and parallel components of the expansion rate of the metric, and we may use radial baryon acoustic oscillations or cosmic clocks to measure the parallel expansion rate. Thus we can test remote isotropy, which is a key requirement of a homogeneous universe. We provide explicit formulas that connect observables and properties of the metric.

Matches accepted version to JCAP; conclusions unchanged; now includes detailed section of the expected S/N of the signal

References in corpus (11)

• Relativistic cosmology and large-scale structure
• A Test of the Copernican Principle
• Precision cosmology defeats void models for acceleration
• Standard rulers, candles, and clocks from the low-redshift Universe
• Cosmic homogeneity: a spectroscopic and model-independent measurement
• Analyzing the cosmic variance limit of remote dipole measurements of the cosmic microwave background using the large-scale kinetic Sunyaev Zel'dovich effect
• The Evolution of the Cosmic Microwave Background
• Measuring Polarized Emission in Clusters in the CMB S4 Era
• Measuring the Expansion of the Universe Through Changes in the CMB Photosphere
• Measuring Space-Time Geometry over the Ages
• Observing the evolution of the CMB

Cited by in corpus (2)

• Another look at redshift drift and the backreaction conjecture
• Multipole decomposition of redshift drift -- model independent mapping of the expansion history of the Universe