Holographic Neutron Stars

TL;DR

This work holographically models degenerate neutron-star-like matter in AdS by constructing degenerate conformal operators and treating them as a degenerate Fermi gas in the bulk. It employs a double scaling limit to separate self-gravity effects and then solves the Tolman-Oppenheimer-Volkoff equations in AdS to locate the Oppenheimer-Volkoff limit, interpreting the limit holographically in the boundary CFT. The results show that self-gravity modestly affects bulk mass and particle number but drives a divergence in the density of states at the OV point, signaling instability and collapse to a black hole, which is interpreted as operator mixing and thermalization to a quark-gluon plasma in the boundary theory. Collectively, the paper links gravitational collapse in AdS to a boundary phase transition, offering a holographic view of dense degenerate matter and its ultimate fate.

Abstract

We construct in the context of the AdS/CFT correspondence degenerate composite operators in the conformal field theory that are holographically dual to degenerate stars in anti de Sitter space. We calculate the effect of the gravitational back-reaction using the Tolman-Oppenheimer-Volkoff equations, and determine the "Chandrasekhar limit" beyond which the star undergoes gravitational collapse towards a black hole.

Figures (3)

• Figure 1: $M$ as a function of $\log \mu(0)$ plotted against $\log m$ for $AdS_5$. The black corner is the "forbidden" region $\mu(0)<m$.
• Figure 2: $M(\epsilon_F)$ plotted against $\log m$. The underlying pink graph is the result without gravity. The units in all figures are $M=\Delta/c$, $\epsilon_F=(n_F\!+\!\Delta_0)/c^{1/(d\!+\!1)}$ and $m=\Delta_0/c^{1/(d\!+\!1)}.$
• Figure 3: The density of states $g(\epsilon)$ plotted against $\log m$. The underlying graph is the result (\ref{['DOS']}) without back-reaction. Here and in FIG.2 the black region corresponds to $\epsilon_F<m$.