Universality and exactness of Schrodinger geometries in string and M-theory
Per Kraus, Eric Perlmutter
TL;DR
This work establishes a universal framework in which Schrödinger-invariant geometries in string/M-theory arise as nonlinear completions of linear KK vector and graviton fluctuations around any AdS×M vacuum, with nonlinearities constrained to quadratic order by AdS symmetry. The dynamical exponent z is fixed by the KK mass via (m_L)^2 = z(z+d-2), enabling infinite families Sch_{d+1}(z) for each AdS background and allowing mixed KK modes to couple only at quadratic order. The authors develop bulk perturbation theory and boundary conformal perturbation theory to justify truncation at quadratic order, derive nonrenormalization theorems for z when deforming KK modes lie in short AdS supermultiplets, and prove exactness in several cases. They present three new explicit Schrödinger constructions (Sch_7 from M5, Sch_3 from D1-D5/F1-NS5, and Sch_4 from wrapped M5) and discuss implications for consistent truncations, higher-derivative corrections, and nonrelativistic holography, including potential RG flows and condensed-matter applications.
Abstract
We propose an organizing principle for classifying and constructing Schrodinger-invariant solutions within string theory and M-theory, based on the idea that such solutions represent nonlinear completions of linearized vector and graviton Kaluza-Klein excitations of AdS compactifications. A crucial simplification, derived from the symmetry of AdS, is that the nonlinearities appear only quadratically. Accordingly, every AdS vacuum admits infinite families of Schrodinger deformations parameterized by the dynamical exponent z. We exhibit the ease of finding these solutions by presenting three new constructions: two from M5 branes, both wrapped and extended, and one from the D1-D5 (and S-dual F1-NS5) system. From the boundary perspective, perturbing a CFT by a null vector operator can lead to nonzero beta-functions for spin-2 operators; however, symmetry restricts them to be at most quadratic in couplings. This point of view also allows us to easily prove nonrenormalization theorems: for any Sch(z) solution of two-derivative supergravity constructed in the above manner, z is uncorrected to all orders in higher derivative corrections if the deforming KK mode lies in a short multiplet of an AdS supergroup. Furthermore, we find infinite classes of 1/4 BPS solutions with 4-,5- and 7-dimensional Schrodinger symmetry that are exact.
