FRW solutions and holography from uplifted AdS/CFT

TL;DR

The paper investigates a holographic description of FRW cosmologies by uplifting AdS/CFT with magnetic flavor branes, yielding time-dependent warped geometries whose infrared regions can be described by a lower-dimensional EFT.A key result is that gravity decouples at late times while the number of degrees of freedom grows, with the covariant entropy bound and a microscopic brane-state count supporting a precise dual description that is non-gravitational in the far future.The authors develop multiple lines of evidence for the dual: a warped FRW metric, dynamics where color branes move up the throat and infrared particles remain bound, and consistent counts of $\tilde{N}_{dof}$ from both quasilocal stress tensors and brane junction combinatorics, all matching the expected time dependence $\tilde{N}_{dof} \sim t^{d-2}$.Correlation functions for massive and massless scalars are computed within the FRW uplift, revealing power-law behavior for KK modes and a Lorentzian, CdL-inspired framework for massless propagators, offering concrete probes of the proposed holographic dual and guiding future refinements.

Abstract

Starting from concrete AdS/CFT dual pairs, one can introduce ingredients which produce cosmological solutions, including metastable de Sitter and its decay to non-accelerating FRW. We present simple FRW solutions sourced by magnetic flavor branes and analyze correlation functions and particle and brane dynamics. To obtain a holographic description, we exhibit a time-dependent warped metric on the solution and interpret the resulting redshifted region as a Lorentzian low energy effective field theory in one fewer dimension. At finite times, this theory has a finite cutoff, a propagating lower dimensional graviton and a finite covariant entropy bound, but at late times the lower dimensional Planck mass and entropy go off to infinity in a way that is dominated by contributions from the low energy effective theory. This opens up the possibility of a precise dual at late times. We reproduce the time-dependent growth of the number of degrees of freedom in the system via a count of available microscopic states in the corresponding magnetic brane construction.

Figures (2)

• Figure 1: Contour $C$ going from $k=-\infty$ above the double pole $k=ik_0$ to $k=+\infty$. Remember $k_0\equiv(d-2)/2$. The simple poles above the double pole are located at $k=i(k_0+n)$, $n=1,2,3,\cdots$. The locations of the simple poles below the double pole are for illustration purposes only and should not be taken too seriously. They depend on the reflection coefficient $R(k)$, and also on whether we are considering the second integrand in \ref{['gexp2']} or in \ref{['gfinal']}. The pair of poles away from the imaginary axis are resonance poles.
• Figure 2: (a) Contour $C_a$ surrounding simple poles at $k=i(k_0+n)$, $n=1,2,3,\cdots$. (b) Coutour $C_b$ surrounding a double pole at $k=ik_0$ and simple poles below $ik_0$. In general there could also be resonance poles away from the imaginary axis in the lower half plane, in which case the contour $C_b$ needs to enclose them as well.