  Twisted bilayer graphene (TBG) realizes a highly tunable, strongly
interacting system featuring superconductivity and various correlated
insulating states. We establish gate-defined wires in TBG with
proximity-induced spin-orbit coupling as $(i)$ a tool for revealing the nature
of correlated insulators and $(ii)$ a platform for Majorana-based topological
qubits. In particular, we show that the band structure of a gate-defined wire
immersed in an `inter-valley coherent' correlated insulator inherits
electrically detectable fingerprints of symmetry breaking native to the latter.
Surrounding the wire by a superconducting TBG region on one side and an
inter-valley coherent correlated insulator on the other further enables the
formation of Majorana zero modes--possibly even at zero magnetic field
depending on the precise symmetry-breaking order present. Our proposal not only
introduces a highly gate-tunable topological qubit medium relying on internally
generated proximity effects, but can also shed light on the Cooper-pairing
mechanism in TBG.
