Physics Group Meeting

I would like to discuss the idea that CFT entanglement explains gravity in AdS/CFT. van Raamsdonk et al. [1] showed that the linearized Einstein equations about the AdS vacuum are equivalent to the entanglement first law in CFT’s, assuming the Ryu-Takayanagi formula. We would like to understand if this argument can be extended to all horizonless asymptotically AdS spacetimes. There are technical problems. It seems a generalization of the Ryu-Takayanagi formula for a different form of entanglement, not organized by position space in the CFT, would be required. One possibility is entanglement among gauged degrees of freedom in the CFT, summed over gauge copies (“entwinement”) [2]. But this proposal is lacking a precise definition.

Recently, Jacobson [3] conjectured that properties of bulk entanglement can be used to derive the nonlinear Einstein equations in any (not necessarily AdS) spacetime. However, his argument relies on some unproved assumptions. I may also discuss this and what it suggests for van Raamsdonk’s argument when put back into AdS/CFT.

References:

1. Faulkner, Guica, Hartman, Myers, van Raamsdonk “Gravitation from Entanglement in Holographic CFT’s” http://arxiv.org/abs/1312.7856

2. Balasubramanian, Chowdhury, Czech, de Boer “Entwinement and the emergence of spacetime” http://arxiv.org/abs/1406.5859

3. Jacobson “Entanglement equilibrium and the Einstein equation" http://arxiv.org/abs/1505.04753