Asymptotics of 5d Supergravity Theories and the Emergent String Conjecture

Abstract

We invoke probe brane arguments to classify the asymptotic behavior of general five-dimensional supergravity theories with eight supercharges near infinite distance boundaries of the vector multiplet moduli space. Imposing consistency of supergravity strings we derive several constraints on the Chern-Simons couplings entering the prepotential, including their non-negativity. This establishes a classification of infinite distance limits analogous to those for theories obtained as Calabi-Yau compactifications, but without having to assume a geometric or string theoretic origin. All infinite distance limits are found to be either vector or tensor limits, depending on the nature of the gauge potential becoming weakly coupled at the fastest rate. In particular, we prove uniqueness results for the asymptotically leading gauge fields. The asymptotic physics along these limits is in perfect agreement with the predictions of the Emergent String Conjecture and hence serves as bottom-up evidence for the latter. Our findings imply that every consistent five-dimensional ${\cal N}=1$ supergravity with a non-compact vector multiplet moduli space either descends from six dimensions or contains a stringy subsector.