  Galactic bars drive the internal evolution of spiral galaxies, while their
formation is tightly coupled to the properties of their host galaxy and dark
matter halo. To explore what drives bar formation in the cosmological context
and how these structures evolve throughout cosmic history, we use the Auriga
suite of magneto-hydrodynamical cosmological zoom-in simulations. We find that
bars are robust and long-lived structures, and we recover a decreasing bar
fraction with increasing redshift which plateaus around $\sim20\%$ at $z\sim3$.
We find that bars which form at low and intermediate redshifts grow longer with
time, while bars that form at high redshifts are born `saturated' in length,
likely due to their merger-induced formation pathway. This leads to a larger
bar-to-disc size ratio at high redshifts as compared to the local Universe. We
subsequently examine the multi-dimensional parameter space thought to drive bar
formation. We find that barred galaxies tend to have lower Toomre $Q$ values at
the time of their formation, while we do not find a difference in the gas
fraction of barred and unbarred populations when controlling for stellar mass.
Barred galaxies tend to be more baryon-dominated at all redshifts, assembling
their stellar mass earlier, while galaxies that are baryon-dominated but that
do not host a bar, have a higher ex-situ bulge fraction. We explore the
implications of the baryon-dominance of barred galaxies on the Tully-Fisher
relation, finding an offset from the unbarred relation; confirming this in
observations would serve as additional evidence for dark matter, as this
behaviour is not readily explained in modified gravity scenarios.
