Geodesically complete metrics and boundary non-locality in holography: Consequences for the entanglement entropy

Gabriele La Nave, Philip W. Phillips

Research output: Contribution to journalArticlepeer-review


We show explicitly that the full structure of IIB string theory is needed to remove the nonlocalities that arise in boundary conformal theories that border hyperbolic spaces on AdS5. Specifically, using the Caffarelli/Silvestri [1], Graham/Zworski [2], and Chang/Gonzalez [3] extension theorems, we prove that the boundary operator conjugate to bulk p-forms with negative mass in geodesically complete metrics is inherently a nonlocal operator, specifically the fractional conformal Laplacian. The nonlocality, which arises even in compact spaces, applies to any degree p-form such as a gauge field. We show that the boundary theory contains fractional derivatives of the longitudinal components of the gauge field if the gauge field in the bulk along the holographic direction acquires a mass via the Higgs mechanism. The nonlocality is shown to vanish once the metric becomes incomplete, for example, either (1) asymptotically by adding N transversely stacked Dd-branes or (2) exactly by giving the boundary a brane structure and including a single transverse Dd-brane in the bulk. The original Maldacena conjecture within IIB string theory corresponds to the former. In either of these proposals, the location of the Dd-branes places an upper bound on the entanglement entropy because the minimal bulk surface in the AdS reduction is ill-defined at a brane interface. Since the brane singularities can be circumvented in the full 10-dimensional spacetime, we conjecture that the true entanglement entropy must be computed from the minimal surface in 10-dimensions, which is of course not minimal in the AdS5 reduction.

Original languageEnglish (US)
Article number126018
JournalPhysical Review D
Issue number12
StatePublished - Dec 30 2016

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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