Another look at redshift drift and the backreaction conjecture

摘要: Earlier studies have conjectured that redshift drift is described by spatially averaged quantities and thus becomes positive if the average expansion of Universe accelerates. This conclusion reevaluated here considering exact light propagation in a simple toy-model with accelerated expansion. The setup explicitly designed for concordance between spatial averages along rays. While it verified redshift-distance relations are well this setup, found not. Specifically, negative despite on-average late-time model. result implies measuring signals at low redshifts gives potential directly falsifying backreaction conjecture. However, results based on so principle possible an artifact reality quantities. therefore highlights importance developing \emph{exact} solutions to Einstein equations which exhibit without local relation observations can be firmly established.