2017/03/31 by Gökhan Alkaç, Gokhan Alkac, Luca Basanisi +2 · 15 citations
Physics and Astronomy · #Black Holes and Theoretical Physics #Boundary (topology) #Classical mechanics #Cosmology and Gravitation Theories #Gravitation #Graviton #Massive gravity #Mathematical physics #Noncommutative and Quantum Gravity Theories #Physics #Quantum mechanics #Spacetime #Theoretical physics #Unitarity #gr-qc #hep-th
paper · pdf · open access · doi:10.1103/physrevd.96.024010
published in Physical review. D/Physical review. D. 96(2) (American Physical Society) · 15 pages, matches the Physics. Rev. D version
arxiv created 2017/07/05 · openalex publication_date 2017/07/11 · arxiv updated 2017/07/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We revisit the problem of the bulk-boundary unitarity clash in 2+1--dimensional gravity theories, which has been an obstacle in providing a viable dual two-dimensional conformal field theory for bulk gravity in anti--de Sitter (AdS) spacetime. Chiral gravity, which is a particular limit of cosmological topologically massive gravity (TMG), suffers from perturbative log-modes with negative energies inducing a nonunitary logarithmic boundary field theory. We show here that any f(R) extension of TMG does not improve the situation. We also study the perturbative modes in the metric formulation of minimal massive gravity---originally constructed in a first-order formulation---and find that the massive mode has again negative energy except in the chiral limit. We comment on this issue and also discuss a possible solution to the problem of negative-energy modes. In any of these theories, the infinitesimal dangerous deformations might not be integrable to full solutions; this suggests a linearization instability of AdS spacetime in the direction of the perturbative log-modes.