Holographic Lifshitz flows and the null energy condition

Abstract: We study asymptotically Lifshitz spacetimes and the constraints on flows between Lifshitz fixed points imposed by the null energy condition. In contrast with the relativistic holographic c-theorem, where the effective AdS radius, L, is monotonically decreasing in the IR, for Lifshitz backgrounds we find that both L and z may flow in either direction. We demonstrate this with several numerical examples in a phenomenological model with a massive gauge field coupled to a real scalar.