title: Positive mass from holographic causality.
abstract: For (n+1)-dimensional asymptotically anti-de Sitter (AdS) spacetimes which have holographic duals on their n-dimensional conformal boundaries, we show that the imposition of causality on the boundary theory is sufficient to prove positivity of mass for the spacetime when n> or =3, without the assumption of any local energy condition. We make crucial use of a time-delay formula relating the Ashtekar-Magnon mass of the spacetime to the time delay of a bulk null curve relative to that of a boundary null geodesic. We also discuss holographic causality for the negative mass AdS soliton and its implications for the positive energy conjecture of Horowitz and Myers.
authors.affiliation: Theoretical Physics Institute, University of Alberta, Edmonton, Alberta, Canada T6G 2J1. don@phys.ualberta.ca
authors.forename: Don N
authors.initials: DN
authors.lastname: Page
authors.forename: Sumati
authors.initials: S
authors.lastname: Surya
authors.forename: Eric
authors.initials: E
authors.lastname: Woolgar