Properties of black hole exterior fermions in spinfoam

We discuss fermion tunneling from the black hole exterior to white hole exterior geometry using the spin foam technique in background-independent Loop Quantum Gravity. The fermion transition time is equal, longer, or shorter than the black hole tunneling time, depending on the Euclidean dihedral angle. For a locally pinched negative curvature, fermions accumulate in the black hole exterior region where the black hole has already emerged from the white hole. Conversely, in locally stretched positive curvature, fermions reach the white hole exterior prior to the black hole, indicating an Einstein-Rosen bridge-like geometry in black hole-to-white hole bounce.