CAUSALITY CONSTRAINT ON NONCRITICAL EINSTEIN-WEYL GRAVITY

We explore, in the context of AdS/CFT correspondence, the causality constraints on the Noncritical Einstein-Weyl (NEW) gravity model in five dimensions. The scalar and shear channels are considered as small metric perturbations around an AdS black brane background. Our results show that the causality analysis on the propagation of these two channels imposes a new bound on the coupling of the Weyl-squared term in the NEW gravity. This new bound imposes more stringent restrictions than those by the tachyon-free condition, improving the predictive power of the theory.