  We study the optical variability of a sample of candidate low-mass (dwarf ang
Seyfert) active galactic nuclei (AGNs) using Zwicky Transient Facility g-band
light curves. Our sample is compiled from broad-line AGNs in dwarf galaxies
reported in the literature with single-epoch virial black hole (BH) masses in
the range $M_{\rm{BH}} \sim 10^{4}$--$10^{8}\ M_{\odot}$. We measure the
characteristic ``damping'' timescale of the optical variability
$\tau_{\rm{DRW}}$, beyond which the power spectral density flattens, of a final
sample of 79 candidate low-mass AGNs with high-quality light curves. Our
results provide further confirmation of the $M_{\rm{BH}} - \tau_{\rm{DRW}}$
relation from Burke et al. 2022 within $1\sigma$ agreement, adding 78 new
low-mass AGNs to the relation. The agreement suggests that the virial BH mass
estimates for these AGNs are generally reasonable. We expect that the optical
light curve of an accreting intermediate-mass black hole (IMBH) to vary with a
rest-frame damping timescale of $\sim$ tens of hours, which could enable
detection and direct mass estimation of accreting IMBHs in wide-field
time-domain imaging surveys with sufficient cadence like with the Vera C. Rubin
Observatory.
