Accelerating Cosmologies from Compactification

TL;DR

This paper demonstrates that time-dependent hyperbolic compactifications can produce accelerated expansion in four-dimensional cosmology, bypassing previous no-go theorems for static compactifications in string/M-theory.

Contribution

It introduces a new class of solutions showing accelerated cosmological expansion from time-dependent hyperbolic compactifications, challenging existing no-go theorems.

Findings

Accelerated expansion achieved in 4D cosmology from higher-dimensional vacuum solutions.

Time-dependent hyperbolic compactifications evade previous no-go theorems.

Compactification volume varies with time, enabling acceleration.

Abstract

A solution of the (4+n)-dimensional vacuum Einstein equations is found for which spacetime is compactified on a compact hyperbolic manifold of time-varying volume to a flat four-dimensional FLRW cosmology undergoing accelerated expansion in Einstein conformal frame. This shows that the `no-go' theorem forbidding acceleration in `standard' (time-independent) compactifications of string/M-theory does not apply to `cosmological' (time-dependent) hyperbolic compactifications.