Hyperscaling violation: a unified frame for effective holographic theories

We investigate systematic classifications of low energy and lower dimensional effective holographic theories with Lifshitz and Schrödinger scaling symmetries only using metrics in terms of hyperscaling violation (θ) and dynamical (z) exponents. Their consistent parameter spaces are constrained by null energy and positive specific heat conditions, whose validity is explicitly checked against a previously known result. From dimensional reductions of many microscopic string solutions, we observe the classifications are tied with the number of scales in the original microscopic theories. Conformal theories do not generate a nontrivial θ for a simple sphere reduction. Theories with Lifshitz scaling with one scale are completely fixed by θ and z, and have a universal emblackening factor at finite temperature. Dimensional reduction of intersecting M2-M5 requires, we call, spatial anisotropic exponents (#), along with z = 1, θ = 0, because of another scale. Theories with Schrödinger scaling show similar simple classifications at zero temperature, while require more care due to an additional parameter being a thermodynamic variable at finite temperature.