  The surprising JWST discovery of a quiescent, low-mass ($M_\star=10^{8.7} \rm
M_\odot$) galaxy at redshift $z=7.3$ (JADES-GS-z7-01-QU) represents a unique
opportunity to study the imprint of feedback processes on early galaxy
evolution. We build a sample of 130 low-mass ($M_\star\lesssim 10^{9.5} \rm
M_\odot$) galaxies from the SERRA cosmological zoom-in simulations, which show
a feedback-regulated, bursty star formation history (SFH). The fraction of time
spent in an active phase increases with the stellar mass from $f_{duty}\approx
0.6$ at $M_\star\approx 10^{7.5} \rm M_\odot$ to $\approx 0.99$ at $M_\star\geq
10^{9} \rm M_\odot$, and it is in agreement with the value $f_{duty}\approx
0.75$ estimated for JADES-GS-z7-01-QU. On average, 30% of the galaxies are
quiescent in the range $6 < z < 8.4$; they become the dominant population at
$M_\star\lesssim 10^{8.3} \rm M_\odot$. However, none of these quiescent
systems matches the Spectral Energy Distribution of JADES-GS-z7-01-QU, unless
their SFH is artificially truncated a few Myr after the main star formation
peak. As supernova feedback can only act on a longer timescale ($\gtrsim 30 \rm
\, Myr$), this implies that the observed abrupt quenching must be caused by a
faster physical mechanism, such as radiation-driven winds.

Astrophysics of Galaxies;Cosmology and Nongalactic Astrophysics