A canonical purification for the entanglement wedge cross-section

Souvik Dutta, Thomas Faulkner

Research output: Contribution to journalArticlepeer-review


In AdS/CFT we consider a class of bulk geometric quantities inside the entanglement wedge called reflected minimal surfaces. The areas of these surfaces are dual to the entanglement entropy associated to a canonical purification (the GNS state) that we dub the reflected entropy. From the bulk point of view, we show that half the area of the reflected minimal surface gives a reinterpretation of the notion of the entanglement wedge cross-section. We prove some general properties of the reflected entropy and introduce a novel replica trick in CFTs for studying it. The duality is established using a recently introduced approach to holographic modular flow. We also consider an explicit holographic construction of the canonical purification, introduced by Engelhardt and Wall; the reflected minimal surfaces are simply RT surfaces in this new spacetime. We contrast our results with the entanglement of purification conjecture, and finally comment on the continuum limit where we find a relation to the split property: the reflected entropy computes the von Neumann entropy of a canonical splitting type-I factor introduced by Doplicher and Longo.

Original languageEnglish (US)
Article number178
JournalJournal of High Energy Physics
Issue number3
StatePublished - Mar 2021


  • AdS-CFT Correspondence
  • Conformal Field Theory
  • Renormalization Group

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


Dive into the research topics of 'A canonical purification for the entanglement wedge cross-section'. Together they form a unique fingerprint.

Cite this