Diving into traversable wormholes

TL;DR

The paper investigates how a simple boundary interaction renders an otherwise non-traversable wormhole traversable in nearly-$AdS_2$ gravity, recasting information transfer as a quantum teleportation through geometry. It derives a general expression for the two-sided correlator that includes gravitational backreaction, showing that backreaction constrains the amount of information that can pass through the wormhole and identifying a regime where the transfer behaves like an unhindered teleportation through an effectively smooth bulk. The authors explore higher-order gravity effects, stringy corrections, and a suite of toy models, including SYK and an operator-growth framework, demonstrating that the traversability phenomenon has broad applicability beyond holographic gravity, extending to classical chaotic systems as well. These results connect the Hayden-Preskill information-decoding picture with explicit bulk dynamics, address cloning paradox concerns, and illuminate how entanglement and bulk geometry cooperate to facilitate information recovery from black holes. The work provides a cohesive framework tying together gravity, quantum information, and chaotic dynamics to understand how information can be transferred through wormhole geometries.

Abstract

We study various aspects of wormholes that are made traversable by an interaction beween the two asymptotic boundaries. We concentrate on the case of nearly-$AdS_2$ gravity and discuss a very simple mechanical picture for the gravitational dynamics. We derive a formula for the two sided correlators that includes the effect of gravitational backreaction, which limits the amount of information we can send through the wormhole. We emphasize that the process can be viewed as a teleportation protocol where the teleportee feels nothing special as he/she goes through the wormhole. We discuss some applications to the cloning paradox for old black holes. We point out that the same formula we derived for $AdS_2$ gravity is also valid for the simple SYK quantum mechanical theory, around the thermofield double state. We present a heuristic picture for this phenomenon in terms of an operator growth model. Finally, we show that a similar effect is present in a completely classical chaotic system with a large number of degrees of freedom.

Figures (18)

• Figure 1: Basic setup. In (a) a message created by $\phi_R$ propagates into the black hole, gets a time advance as it crosses the negative energy associated to $O_LO_R$, and emerges on the left side. In (b) the same configuration has been boosted. In (c) we show the case where $O_R$ is measured, resulting in some positive energy shooting in from the right but the same negative energy on the left. The diagrams are drawn in discontinuous coordinates so that a continuous worldline gets a backwards null shift as it crosses the blue negative energy.
• Figure 2: In (a) we show a two-graviton exchange that contributes at leading order in $g$. This is proportional to $g\cdot(G_Ne^t)^2$. At higher orders in $g$ we have more $O$ quanta, and we sum diagrams including those in (b).
• Figure 3: Real part (blue, solid) and imaginary part (red, dashed) for the correlator $C$, with $\Delta = 0.7$. (a) correspond to the probe approximation (\ref{['ResFi']}) and (b), (c) to the full result (\ref{['ResGen']}) (after getting $C$ via (\ref{['TiCdef']})). The horizontal axis is $t + \log(G_N)$.
• Figure 4: Real part (blue, solid) and imaginary part (red, dashed) for the correlator $C$, with $\Delta = 0.7$ and the stringy parameter $a = \frac{1}{2}$. The horizontal axis is $t + \frac{1}{1-a}\log(G_N)$. (a) Is the probe approximation (\ref{['StrCase2']}). (b) and (c) describe the full result at finite $g$.
• Figure 5: A classical solution for a single boundary trajectory in Lorentzian AdS${}_2$ (a) and Euclidean AdS${}_2$ (b). In (c) we show the pair of boundaries associated to the thermofield double. The projection of the vector $Q$ onto AdS${}_2$ is the bifurcation point.