  Recent observations of high-redshift galactic disks ($z\approx 1-3$) show a
strong negative trend in the dark matter fraction $f_{DM}$ with increasing
baryonic surface density. For this to be true, the inner baryons must dominate
over dark matter in early massive galaxies, as observed in the Milky Way today.
If disks are dominant at early times, we show that stellar bars form promptly
within these disks, leading to a high bar fraction at early times. New JWST
observations provide the best evidence to date for mature stellar bars in this
redshift range. The disk mass fraction $f_{disk}$ within $R_s=2.2 R_{disk}$ is
the dominant factor in determining how rapidly a bar forms. Using 3D hydro
simulations of halo-disk-bulge galaxies, we confirm the "Fujii relation" for
the exponential dependence of the bar formation time $\tau_{bar}$ as a function
of $f_{disk}$. For $f_{disk} > 0.3$, the bar formation time declines
exponentially fast with increasing $f_{disk}$. This relation is a challenge to
simulators - barred models with inadequate resolution fall off this curve.
Instead of Fujii's arbitrary threshold for when a bar forms, for the first
time, we exploit the exponential growth timescale associated with a positive
feedback cycle as the bar emerges from the underlying disk. A modified,
mass-dependent trend is observed for halos relevant to systems at cosmic noon
($10.5 < \log M_{halo} < 12$), where the bar onset is slower for higher mass
halos at a fixed $f_{disk}$. If baryons dominate over dark matter within $R
\approx R_s$, we predict that a high fraction of bars will be found in
high-redshift disks long before $z = 1$. Due to its widespread use in
simulations, we investigate the Efstathiou-Lake-Negroponte criterion for bar
instability: this sub-optimal parameter is inversely related to $f_{disk}$,
with a secondary dependence on $M_{halo}$.
