Anisotropic scale invariant cosmology

TL;DR

This paper explores anisotropic scale-invariant cosmologies within Einstein gravity, requiring null energy condition violation, and proposes a dual non-unitary field theory with potential implications for big bang/crunch singularities.

Contribution

It introduces a ghost condensation model to realize anisotropic scale invariance in cosmology, linking it to non-unitary dual field theories and singularity resolution.

Findings

Null energy condition violation is necessary for anisotropic scale invariance.

Constructed a cosmological model with at least one contracting spatial direction.

Potential dual description involving winding tachyon condensation to address singularities.

Abstract

We study a possibility of anisotropic scale invariant cosmology. It is shown that within the conventional Einstein gravity, the violation of the null energy condition is necessary. We construct an example based on a ghost condensation model that violates the null energy condition. The cosmological solution necessarily contains at least one contracting spatial direction as in the Kasner solution. Our cosmology is conjectured to be dual to, if any, a non-unitary anisotropic scale invariant Euclidean field theory. We investigate simple correlation functions of the dual theory by using the holographic computation. After compactification of the contracting direction, our setup may yield a dual field theory description of the winding tachyon condensation that might solve the singularity of big bang/crunch of the universe.