Supersymmetric Janus solutions in four dimensions

We use maximal gauged supergravity in four dimensions to construct the gravity dual of a class of supersymmetric conformal interfaces in the theory on the worldvolume of multiple M2-branes. We study three classes of examples in which the (1+1)-dimensional defects preserve (4, 4), (0, 2) or (0, 1) supersymmetry. Many of the solutions have the maximally supersymmetric AdS 4 vacuum dual to the N = 8 ABJM theory on both sides of the interface. We also find new special classes of solutions including one that interpolates between the maximally supersymmetric vacuum and a conformal fixed point with N = 1 supersymmetry and G2 global symmetry. We find another solution that interpolates between two distinct conformal fixed points with N = 1 supersymmetry and G2 global symmetry. In eleven dimensions, this G2 to G2 solution corresponds to a domain wall across which a magnetic flux reverses orientation.