  Tunneling of quasiparticles between two nearly-aligned graphene sheets
produces resonant current-voltage characteristics because of the quasi-exact
conservation of in-plane momentum. We claim that, in this regime, vertical
transport in graphene/boron nitride/graphene heterostructures carries precious
information on electron-electron interactions and the quasiparticle spectral
function of the two-dimensional electron system in graphene. We present
extensive microscopic calculations of the tunneling spectra with the inclusion
of quasiparticle lifetime effects and elucidate the range of parameters
(inter-layer bias, temperature, twist angle, and gate voltage) under which
electron-electron interaction physics emerges.
