Diving into a holographic multi-band superconductor

In this work, we investigate the interior structure of a holographic multi-band superconductor model. We focus on the holographic superconductor system with two scalar fields which correspond to two s-wave order parameters in the dual condensed matter system. We discover a new kind of transition rule among Kasner universe near the black hole singularity which is distinct from the holographic single-band superconductor model. This transition rule is the first generalization of Kasner transition behavior to scenarios involving multiple free parameters, which is useful for uncovering the most general interior structures of hairy black holes. Moreover, we find that the Kasner exponents are sensitive to the details of order parameters in boundary system. These different near singularity structures we found show that the black hole interior plays crucial role in characterizing the boundary dual condensed matter systems.